JPH0817269B2 - Circuit lighter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Contrast with Related Patent Application This application is a partial continuation of US Patent Application No. 193,291 “CIRCUI WRITER” filed on May 11, 1988, May 11, 1985. The application is a partial continuation of US Patent Application No. 192,523 "CIRCUI WRITER MATERIALS".

FIELD OF THE INVENTION The present invention relates to circuit board fabrication and, more particularly, to an apparatus for forming conductive circuits by extrusion between points on a circuit board.

BACKGROUND OF THE INVENTION There has been a rapid growth of the electronics industry in the United States and around the world for at least the past 25 years, an important and essential area of which was the development and manufacture of printed circuit boards. These printed circuit boards are typically in such a manner that electrical and electronic components, such as resistors, capacitors, integrated circuits, transistors, etc., can be mounted to produce an electrical circuit incorporating those components. And non-conductive substrate (ie plate)
Formed by conductive traces (trajectories) supported by. The conductive traces are the "wires" of the circuit, and the boards provide structural integrity, convenience for mounting to the chassis frame, and support for connecting to other circuits. Printed circuit boards are an integral part of almost every electronic product,
Often the most complex and expensive part of the overall system.
For example, all of the operating components and electronic memory of many computers are incorporated on one or more printed circuit boards.

Desktop computers are a good example of products that make extensive use of printed circuit boards. The development of integrated circuits has helped the development of desktop computers, the basis of which is a powerful central processing unit (CPU) and memory chips capable of storing large amounts of digital information. The motivation for more powerful processing power, such as the formation and display of complex graphics, has resulted in miniaturization techniques for incorporating more devices into a single integrated circuit chip. Based on the same motive, innovative techniques to increase the density of printed circuits, in a limited space environment such as the chassis of a desktop computer,
A large number of memory chips and processors have been operated.

As in all product development, some techniques have recently emerged for making printed circuit boards that have proven useful and effective and have become used by many manufacturers. . 1985 Van Nostrand (Va
Published by n Nostrand, Raymon N. Clark
Printed Circuits Handbook (Handboo) by d N. Clark
According to one such process, as described in K of Printed Circuit Manufacturing, a typical printed circuit board begins with a sheet of non-conductive polymer material, such as glass fiber reinforced epoxy. The material that ultimately forms the trace is copper foil, and a thin sheet of copper foil is attached to one or both sides of the glass fiber sheet, typically with epoxy resin as an adhesive, to form a blank (semi-finished product). This layered blank is usually perforated. While some of the holes are for purposes such as applying this plate to other elements of the assembly, centering, and mounting, many holes are for electrical components to be finally mounted on the final product plate. There are many holes for receiving the leads and allowing the final traces on one side to contact the traces on the other side through the lamination plate.

If, after drilling, a conductive metal, usually copper, needs to be plated in the holes, electroless plating operations are used. Thereafter, imaging techniques are used to spread the pattern defining the circuit trace to be formed on the copper foil. Two widely used techniques are silk screen and dry film photoresist. In each of them
A pattern called a block copy is determined separately and masked as part of the process. In the silk screen process, a plating resist material is applied to the copper foil through an open portion of the mask. In the dry film photoresist process, the entire copper foil area is coated and then the pattern is cured through a mask with radiation such as ultraviolet light. Thereafter, the uncured photoresist is washed away. In each case, the result is a pattern of plating resist material on the copper foil that covers the area of the foil that will eventually be removed leaving a circuit pattern. The resist will not match the pattern of the circuit trace, but will match the non-circuit pattern, ie, the negative of the trace.

The next step in the typical process is the plating finish of the circuit pattern. Conventional plating techniques are used to thicken the exposed copper foil of the circuit pattern to a predetermined thickness to provide the proper current conducting cross section and structural integrity.
The plating operation is typically completed by overlaying the trace with a layer of material such as tin-lead alloy (solder). Next, the resist is usually removed by solvent washing, and the foil under the resist is removed by chemical etching. Overplating of the solder material protects the circuit traces from corrosive liquids. A conductive circuit is left on the surface of the plate.

There are many tasks performed that are not detailed in this description, such as reflow and solder mask. The purpose of this description is not to teach how to fabricate printed circuit boards by conventional techniques, but to show that it is a rather complex, time consuming and expensive process. A single plate, even in volume production, can cost hundreds of dollars, and applying these techniques to a limited amount of plates can cost several thousand dollars per plate.

Numerous innovations have been made in the development of circuit board fabrication techniques, especially to increase complexity and density. Paths of development include stacking boards to create the inner layers of complex circuits.

Connections to the board elements and other layers of circuitry are made by vias through holes and non-conductive board material. These are known to those skilled in the art as multilayer boards and have multiplied the amount of circuitry that can be accommodated in an equal board space.

Another development was the use of polymeric thick film materials in the preparation of printed circuit boards, especially multilayer boards. Thick polymer films are conductive materials (eg, silver particles).
Alternatively, the use of an additive causes thixotropy, such as when mixing a thixotropic additive (eg, fused silica). It is a polymeric material (ie a plastic resin). These are silk screen printed directly on the surface of the non-conductive plate, directly forming conductive traces. Used in multi-layer technology,
The layers of the silkscreen printed circuit are stacked in alternating layers with other materials and printed circuits, with the connections between the layers being made by vias and perforated and plated holes. In general, the price of polymeric thick film multilayer boards can be half the price of multilayers of laminated copper.

Even with this and other new developments, there are serious problems that are still unsolved, problems that are brought from one technology to the next. One of them is to apply to the formation of traces on the plate under the plate. The first step in making a board is the engineering stage. The theoretical circuit is considered and the circuit performance is calculated. Next, components are typically specified from off-the-shelf components such as one manufacturer's CPU, another manufacturer's DRAM, and other elements from another manufacturer,
Calculations are made to determine the required trace. For example, some limitations may be imposed on the length of certain traces where very high speeds of signal transmission are required, or on the cross-sectional area and conductivity where high current loads must be tolerated. There are other engineering considerations such as expansion and contraction relationships between traces and supports, and cooling and heat spread requirements. In these calculations, the design engineer is also constrained by the nature of the prototype development and production equipment used to put the design into practice.

In today's work environment, design engineers are often assisted by new powerful computer programs that take into account all design conventions, calculate, and create trace pattern graphic displays. The patterns created are called routes, and the software tools are called routers. The router engine is the basic computing tool that quickly implements the many possible alternative layouts while still adhering to the general rules of all routers.
It is important to note that, after the routing and the iterative process of selecting the options created by the computer, the route has to be incorporated into the plate prototype or the composition to be transferred to the mass production process. Conventional processes require a mask for silk screen printing of photoresist or plating resist. The polymer thick film process requires a silk screen to coat uncured material on the board surface.

The use of block copy introduces expensive, time consuming intermediate steps and also increases the chance of errors such as inconsistencies.

Another issue that is still present and even more complex is the absolute need to verify a design before moving it to a costly and cumbersome production process. This process, known as the bulletboard process, appears to work, and preferably in a relatively inexpensive way to verify that the circuit that engineering calculations have shown to work actually works in the real world. , It is a practice to make a limited number of plates. One method used for breadboards is that there are no circuit traces, but the circuit elements are attached to a standard board with edge pads and other somewhat standard characteristics, using fine wires or other hand-traceable trace material.
Connecting various elements by soldering or wire winding. This process is of course cumbersome and error prone. Other breadboard techniques include techniques that are substantially equivalent to those used in mass production, but such as small plating tanks for processing one or a few plates at a time,
Use smaller facilities or hand-operated equipment than dedicated to mass production.
This process is also expensive and time consuming.

The breadboard process is over, the iterative correction process is complete,
Another very typical problem arises when a large number of plates are produced. Technological changes such as adding one or two elements to improve performance are often required. Result is,
It represents a large expense, which results in a large stock of finished boards that must either be scrapped or repaired at unacceptable costs. The process of turning this stock into a usable or marketable product involves cutting the traces,
Includes adding jumper wires. The process of cutting and jumping is generally manual and therefore error-prone and, for the same reasons, extremely expensive. Moreover, the changes made are often made in a way that is unfamiliar to the mass-production process, so that they are clearly visible. Many believe that cutting and the presence of jumpers are a good way to determine the technical foresight of a company that manufactures printed circuit boards. Many product verifiers also partially evaluate products by cutting and jumpers present on the printed circuit boards used.

There is a need for a computer controlled device that allows computer assisted engineering and computer generated routing and related production to be done directly on or loaded into the control computer so that printed circuits can be produced directly by the device. . Eliminate the intermediary step of implementing the master in another form, such as a mask to apply photoresist or plating resist, and also remove the resist and plating finishing operations, to get the maximum benefit. , Such devices produce traces that can cross each other (ie giving crossover)
This should be the case, and the density of the multi-layer board will be increased as well. Direct writing of traces from digital data integrates all the complex stages of printed circuit board production,
It will especially help the breadboard process. Such a direct circuit writer would also significantly improve the process of repairing in the form of cuts and jumpers. In boards made by such circuit writers, cutting and jumpers can be programmed and automated, and will be difficult to distinguish from the original trace. Such devices, if properly programmed and automated, can be used to provide jumpers on conventional boards (with accessible traces) to provide expensive and error prone manual repairs. Could be deleted.

SUMMARY OF THE INVENTION In accordance with a preferred embodiment of the present invention, an apparatus is disclosed for conditioning conductive traces on a circuit board using an additive technique rather than a wet process removal technique. The traces are written directly in successive steps, rather than in parallel steps as in the silk screen technique, and each trace can be individually isolated. Thus, crossover becomes customary, allowing electrical contact to the element without vias, while at the same time simulating a multilayer board conditioned by other processes. The inherent freedom to track virtually any pattern allows complex circuits to be easily and quickly pretboarded in hours rather than usually days or weeks. Is especially important in the sense that Further, the device in the preferred embodiment is computer controlled and can be operated by instructions provided by computer generated routing programs and computer assisted engineering programs. In addition, jumpers for existing boards can be easily programmed. Also, due to the automated direct writing capability, it is possible to process the production of small quantities, which is generally very expensive per plate in a parallel production process, very inexpensively and rapidly.

The device according to the invention comprises a stage and a first extrusion element for extruding a first material. Holding the extrusion element and the circuit board in relative proximity to extrude the first material along a preselected path on the surface of the circuit board to produce conductive traces, and It is the purpose of the stage to create relative motion with the circuit board. Next, it is desirable to cover the conductive traces with an insulating material to provide insulated conductive traces. More desirably, the apparatus includes a second extrusion element that extrudes a second material onto the conductive traces to produce an insulated conductive trace. Most preferably, the first and second materials are polymer solutions that form a thick polymer film after the curing step.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a first preferred embodiment of the present invention, and FIG. 2A is a typical base plate and rail mechanism of the first preferred embodiment, which is necessary for circuit writing. Precise x, y, z
Perspective view showing only the main framing elements and bearing / rail mechanics for imparting axial movement, Figure 2B shows a rail assembly adjacent to the saddle carriage, perpendicular to the length of the rail assembly, viewed in the x direction. FIG. 2C is a three-dimensional sectional view showing elements constituting the saddle carriage, FIG. 2C is a sectional view taken along line 2C-2C of FIG. 2B, FIG. 2D is a sectional view of a cross rail assembly according to the present invention, and 2E. FIG. 2 is a sectional view of a shaft and a spacer rail adjacent to a writing carriage according to the present invention, and FIG. 2F is a sectional view taken along the line AA of FIG. 2E, which passes through a base block of the writing carriage according to the present invention. 2G is an end view similar to FIG. 2D of the opposite end of the close rail assembly, and FIG. 2H shows elements not shown in the other views, as used with the preferred embodiment of the present invention. The top view of the trash table, Figures 3A and 3B are the write carriers. Can move in the y direction, illustrates one way desired, Figure 3C shows the Y driving device according to the invention in front view,
3A is a sectional view taken along the line 3B-3D of FIG. 3C, and FIG. 3E is a sectional view taken along the line 3E-3E of FIG. 3C. 4A is a plan view of an x-motion assembly according to the present invention; FIG. 4B shows winding of a cable around a drive motor and drum used in the x-motion assembly of FIG. 4A;
Enlarged view, FIG. 4C is a view from the 4C-4C surface of FIG. 4B, FIG. 4D is a view from the 4D-4D surface of FIG. 4B, and FIG. 4E is a 4E- view of FIG. 4B. 4E is a view seen from the 4E plane, FIG. 4F is a view seen from the 4F-4F plane of FIG. 4A, FIG. 4G is a perspective view of a part of one end of the preferred embodiment of the present invention, and FIG. 4G is a perspective view of a portion of the other end of the preferred embodiment shown in FIG. 4G, FIG. 4I is a perspective view of the touchpad when used in the preferred embodiment for setup purposes, and FIG. FIG. 6A is a side view of the writing carriage seen from the same direction as FIG. 2E, and FIG. 6B is a line 6B-6B of FIG. 6A. An elevation view of the writing carriage at a 90 ° angle to the view of Figure 6A, as seen in the orientation, Figure 6C is a view of a portion of the writing carriage as viewed from the 6C-6C plane of Figure 6B, Figure 6D shows the z-axis of the device FIG. 6C is a perspective view of a portion of the tongue strip shown in FIG. 6C used to convert rotational motion into linear motion, and FIGS. 6E and 6F show the flow of extruded material during circuit writing. 2 of the three-way valve according to the present invention used for
FIG. 6G is a view of the elements that make up the writing tip according to the present invention; FIG. 6H is a view of the desired shape of a hypodermic tubular tip for extruding traces of conductive PTF material. Figures, Figure 6I shows a preferred shape of a hypodermic syringe-like tubular tip for extruding a trace of non-conductive PTF material, and Figure 6J shows the use of the tip of Figure 6H when writing a trace. FIG. 6K is a diagram showing the use of the chip of FIG. 6I when writing traces; FIG. 7A is a plan view of a preferred alternative embodiment of the present invention; FIG. 7B is a plan view 7B-7B of FIG. 7A. Figure 7C is a cross-sectional view of the preferred alternative embodiment taken along a plane; Figure 7C is a view of the crossrail assembly taken from the plane 7C-7C of Figure 7A; Figure 7D is the direction of line 7D-7D of Figure 7C. Figure 7E is a diagram of the writing carriage seen in Figure 7, Figure 7E is a diagram showing the mechanism of the pulley of the alternative embodiment seen in the direction of line 7E-7E in Figure 7A, and Figure 7F is Another view, showing the cable path of an alternative embodiment, looking in the direction of line 7F-7F in FIG. 7A, is shown in FIG. 8A, FIG. 8A, FIG. 8B, and FIG. 8C, which is a wide range used to automate the present invention. FIG. 9 is a block diagram showing a flow of information, FIG. 9 is a block diagram showing a process control function used for operating the present invention, and FIG. 10 is a printed circuit board manufactured by the circuit writer of the present invention. FIG. 11 is a view showing a typical pad used, FIG. 11 is a view showing a typical relationship between pads used on a printed circuit board manufactured by the circuit lighter of the present invention, and FIG. 12A is a view showing the present invention. FIG. 12B shows a portion of a printed circuit board having pads and traces written with the circuit writer of FIG. 12B, two pads on one side and an extrusion of a two layer printed circuit board made with the circuit writer of the present invention. Figure 12C shows the traces taken and Figure 12C shows the trace taken along line 12C-12C in Figure 12B. Sectional view, Figure 12D shows two pads and traces on the opposite side of the printed circuit board of Figure 12B, and Figure 12E shows a four layer printed circuit board made with the circuit lighter of the present invention. Diagram showing two pads and extruded traces on one side, FIG. 12F is a cross-sectional view taken along line 12F-12F in FIG. 12E, and FIG. 12G is the other side of the four-layer circuit board in FIG. 12E. Diagram showing certain two pads and traces, Figure 12H is a plan view of two pads and one composite trace, and Figure 12I is a cross section of the composite trace of Figure 12H taken along line 12I-12I. FIG. 13A is a side view of a write carriage according to an alternative embodiment of the present invention, referred to as a Minibung embodiment, and FIG. 13B is a write carriage 13B-1 shown in FIG. 13A.
3B view, FIG. 14A is a cross-sectional view of a portion of the mini-bang embodiment, FIG. 14B is a cross-sectional view similar to FIG. 14A in which the operating parts are at different positions, and FIG. 15 shows the machining head. Side view of carriage for retention, Figure 16A is a partial cross-sectional view of the circuit, Figure 16B is a plan view of a portion of a circuit board with milled pads, Figure 16C is the pad of Figure 16B. 16D is a partial cross-sectional view of FIG. 16C after the supplemental step, FIG. 17A is a cross-sectional view of the circuit board blank, and FIG. 17B is a supplemental step after the supplemental step. 17A is a cross-sectional view of the circuit board of FIG. 17A, FIG. 17C is a cross-sectional view of the conductive trace shown in FIG. 17B, and FIG. 17D is a cross-sectional view of the insulating trace over the conductive trace of FIG. 17C. FIG. 18A is a plan view of an alternative method of forming traces between pads, and FIG. 18B is a plan view of the plate shown in FIG. 18A. FIG. 18C is a partial cross-sectional view of the finished plate using the alternative approach of FIG. 18A, FIG. 19A is a plan view of a polymer pad formed by extrusion, and FIG. , A partial cross-sectional view of the polymer pad of Figure 19A, Figure 19C is another partial cross-sectional view of the polymer pad of Figure 19A, as viewed in a direction orthogonal to Figure 19B, Figure 20. Sectional view of a clad plate electrically connected from one side to its opposite side using the extruded polymer used in the circuit lighter of the present invention, Figure 21A shows electrical connection from one side of the plate to its opposite side. 21B shows a plan view of the plate shown in FIG. 21A, and FIG. 22A shows how to provide lead alignment to separate devices to be attached to the pad FIG. 22B is a cross-sectional view of the polymer pad of FIG. 22A, FIG. 23A and FIG. And Figure 23B is a cross-sectional view of the plate showing the continuation of steps to make a lead aligned polymer pad according to an alternative embodiment, and Figure 23C is according to the method of Figures 23A and 23B. FIG. 23D is a plan view of the pad at an intermediate stage, and FIG. 23D is a sectional view of the pad of FIGS. 23A to 23C at the time of completion.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates an exemplary apparatus for writing traces on a circuit board by applying a conductive material, such as a metal-blended epoxy, in a predetermined pattern on the surface of a support blank (hereinafter , Referred to as a circuit writer). In a preferred embodiment, the conductive material is applied by extrusion in a paste or semi-liquid form and then cured to form a permanent conductive path between the circuit elements. The circuit elements are added later to make a printed circuit board (PCB). Optionally, the circuit lighter is also used to apply the electrical insulation material, also in paste or semi-liquid form. The support blank is typically a sheet of reinforced plastic, such as glass reinforced epoxy, which is typically non-conductive.
The blank may be perforated with different small diameter holes through which the metal leads of the circuit element are threaded, after which the leads are secured to a portion of the conductive passages applied by the circuit lighter. Newer PCB designs allow circuit elements to be mounted on the surface and element leads do not pass through the holes in the board, and the resulting board is an STM.
It is called (surface mount technology). In either case, fixing the element leads to a portion of the conductive path on the plate is done by soldering or by a conductive adhesive such as a metal-mixed epoxy.

In the first preferred embodiment shown in FIG. 1, the circuit lighter includes two parallel rail assemblies (11, 13) mounted on a stable base plate (15). Saddle carriage (1
7) straddles along the rail assembly (11), saddle carriage (19) straddles along the rail assembly (13),
The saddle carriage and rail assembly form an x-direction rail / bearing subassembly. The saddle carriages (17, 19) are firmly connected by the cross rail assembly (21), and the writing carriage (23) straddles the rail assembly (21).
The bearings in the write carriage form the y-direction rail / bearing subassembly with the cross rail assembly. As a result of this right-angled mechanism of the two rail / bearing sub-units, the writing carriage (23) has two degrees of freedom and can move in the x direction indicated by the arrow (25) and the y direction indicated by the arrow (27). You can
x-drive (29) combined saddle carriage (17,19)
In the x direction, and the y drive section (31) drives the write carriage in the y direction. Table in xy system (33)
Serves to carry the blank (41) on which the circuit is written.
A metering device that can start, stop, and adjust the PTF flow is provided, carried with the write carriage (23), and through a write extension (37) extending from the carriage in a generally vertical direction. It contains a tank (35) of uncured PTF which is quantified by a number of factors (not shown). In another embodiment, the material tank is stationary with respect to the frame of the device,
Material can be guided to the write carriage through flexible tubing. The writing extension (37) should be placed on the writing table (33) in the immediate vicinity of the pcb blank (41), with the arrow (3
It can move vertically in the direction of 9).

A computerized control system (43) is connected to the mechanical system to power and control the movement of the writing element and the starting, stopping and metering of the material in response to programmed information. In FIG. 1, the control system and its connection to the mechanical system are not shown in detail.

The perspective view of FIG. 2A illustrates a typical base plate and rail device of the preferred embodiment, which illustrates the precision required for circuit writing.
Only the main framework elements and bearing / rail arrangements for providing x, y, z motions are shown. In a preferred embodiment, a base plate (1) is provided from a solid, empty steel plate having a length (D1) of about 990 mm, a width (D2) of about 840 mm, and a thickness (D3) of about 25 mm to provide rigidity.
5) is cut. In a preferred embodiment, cutouts are made in the body of the base plate to reduce the weight of the member. This cutout is not shown in Figure 2A but has no other function. It will be apparent to those skilled in the art that the traces created on a printed circuit board by a circuit writer must typically be of very small cross-sectional area. The device of the present invention allows the writing of narrower or wider traces, but with a width of 12 mil (0.30 mm) and a height of 6
A mil (0.15 mm) trace is typical. The traces typically have an arcuate cross-sectional shape, generally a semi-circular or semi-elliptical cross-sectional shape, and although the thickness is sometimes somewhat less than 50% of the width, the thickness is generally representative in the preferred embodiment. Is at least 25% of the width, and is preferably much thicker than 25%. By making the traces narrower and thicker, the trace density on the circuit board surface can be increased. A circuit design for electrically connecting elements mounted on a board may require one trace to be very long and may require separate traces to be in close proximity. . Traces that should not touch in the wiring diagram are 10mils (0.25m) from each other.
It is not uncommon to be within m). Typical geometric figures on printed circuit boards are small and precise,
It is very important that the mechanism carrying the write carriage be mounted on a flat and stable foundation or that any changes in the flatness or stability of the foundation be compensated for in the drive. Thus, in the preferred embodiment, the foundation and other framework elements are relatively stout to provide the required stability. Another advantage of using solid framework elements is that they exhibit a correspondingly large heat capacity and therefore slow dimensional change in response to changes in ambient temperature.

The rail assembly (11) in the typical arrangement of Figure 2A.
Comprises a T-rail (45), a hardened, ground shaft (47) and three supports (49,51,53). Support (49,51,53)
Is machined from a single steel block and is relatively solid to provide dimensional stability. The support is mounted on the base plate by fasteners (not shown) and the T-rail is mounted on the support by fasteners (not shown). The ground shaft (47) is mounted by bolts (not shown) on top of the T-rail so that the shaft is centered laterally on the rail. It is assembled so that the center of the shaft (47) is typically 125 mm (D4) upward from the upper surface of the base plate (15) and the center line of the shaft is parallel to the long side of the base plate.

The rail assembly (13) is similar to the rail assembly (11),
T-shaped rail (55), ground shaft (57) and support (5
9,61,63) are included. The axis (57) is parallel to the axis (47) at the same height (D4) as the axis (47) from the upper surface of the base plate (15), and in order to restrain the writing carriage in the x direction, The two axes together form a double orbit. The shaft distance D5 is typically about 840 mm, and Thompson Industries (Thomp
Commercially available grinding shafts, such as the case 60 shafts of Son Industries, are suitable, but other types of shafts can be used. The set of x-direction rails is approximately centered on the base plate (15) in both the x and y directions, respectively, as indicated by arrows (65,67).

As mentioned earlier, there are two saddle carriages (17, 19) carrying linear bearings to constrain movement in the x direction. The saddle carriage (17) is associated with the rail assembly (11) and the saddle carriage (19) is associated with the rail assembly (13). Each saddle carriage supports a mounting block. The installation block (69) is fixedly attached to the saddle carriage (17), and the installation block (70) is fixedly attached to the saddle carriage (19). Crossrace assembly (21)
Joins both mounting blocks so that both blocks are firmly co-held and carry the cross rail assembly (21) for co-movement in the x direction.

The saddle carriage (17) has a round through-hole as shown in FIG. 2B, which shows a cross section through the rail assembly (11) adjacent to the saddle carriage, which is perpendicular to the length of the rail assembly when viewed in the x direction. It has a cavity (75) and an elongated opening (73) with a rectangular notch (77).

Along the length of the through-hole cavity (75) and rectangular notch (77)
The linear bearings (79, 81) are mounted inside the through bore (75) and engage the shaft (47) as illustrated in Figure 2C, which corresponds to section 2C-2C in Figure 2B. , Saddle carriage (17) Constraint to move along axis (47). Bearing (79,8
1) can be a split ball bushing like the Thompson Industrial Series XR, a super-rigid open ball bush.
Other similar components can also be used. Since the open ball bush does not completely surround the shaft and has an open portion, the shaft with which the bearing engages is supported along the entire length of the shaft and complements the rigidity of the mechanical system. FIG. 2B shows the bearing (79) as seen from the end face, and the bearing is open by the width of the notch (77). Since the notch (77) is wider than the vertical part of the T-shaped rail (45), the carriage (17) is not interfered and the shaft (4
7) Can move along the length of. Installation of the saddle carriage (19) on the shaft (57) is done by the saddle carriage (17)
By an assembly similar to that shown in FIG.

In the cross-sectional view of the cross rail assembly (21) shown in FIG. 2D, a strut saddle (97) firmly attached to a mounting block (71) that rides on a saddle carriage (19) (not shown).
Is illustrated. The cross rail support (93) is attached to the support saddle (97) by the fastener (107), and the adjustment screws (101, 99) screwed into the vertical portions of the support saddle (97) are respectively supported by the support (93). Abutting the lower surfaces on both sides of. The hole in the post (93) through which the fasteners (107,109) pass is sufficiently larger than the diameter of the fastener so that the position of the post (93) is within the saddle (9) within the limits imposed by the saddle.
7) Can be adjusted for. The use of this adjustment is to square the cross rail assembly to the x-direction rail assembly, with a similar mechanism associated with the saddle carriage (17) on the opposite x-direction rail assembly. If this position is correct, the column (93) and the opposite x
Fasteners can be tightened to lock similar stanchions on the directional rail assembly to form a solid assembly. Figure 2G shows
FIG. 2B is a view from the opposite side of the crossrail assembly as viewed in the direction of arrow (84) in FIG. 2A, showing the elements that make up that end of the crossrail assembly.

The cross rail assembly (21) has two hardened and precision ground shafts similar to the shafts (47,57) of the x-direction rail assembly. The axes are positioned horizontally in the assembly, one above the other, at a right angle to the x-direction rail assembly. The shaft (85) is the upper of the two and the shaft (87) is the lower. The two shafts are ground through stanchions (93) to fit into vertical windows (129) with rounded upper and lower ends. The radius of each rounded end is substantially equal to the radius of the axis (85,87). The shaft has two spacer rails (89,9
The rails themselves are held in place by the set screws (103, 105), which are separated by 1) and held in place. The stanchions (95) carried by the saddle carriage (17) (Fig. 2A) support the opposite ends of the shafts (85,87) and spacer rails (89,91) so that the shafts (85,87) are in the x direction. Form an upper and lower cross rail assembly perpendicular to the rail assembly. The longitudinal movement of the crossrail assembly is in the y direction (by definition).

The axis (8) adjacent to the writing carriage (23) (Fig. 2A)
5,87) and a spacer rail (89,91) in section 2.
The E view shows an empty base block (119) with two round bores (123,125) and a cut passage (121) with a rectangular notch (127) connecting them. Pore cavity (12
The center-to-center distance between 3,125) is the axis (85,8) of the crossrail assembly.
7) Equal to the distance between hearts.

As shown in FIG. 2F, which is a cross-sectional view of the write carriage base block taken along the line AA in FIG. 2E, the linear bearings (111, 113) are respectively provided in the bores (125, 123) on one side of the block (119). ) Is incorporated and engages the shaft (87, 85). The linear bearings (115, 117) are incorporated in the block (119) on the side opposite to the bearings (113, 111) and engage with the shafts (85, 87). The bearing is a split linear ball bushing of the same type used in the x-direction rail assembly, this mechanism moves the carriage base block (119) only in the y direction relative to the axis (85,87). To restrain. Block (11
9) forms the basis on which the elements of the writing carriage can be firmly mounted. Structural plates, framing elements and other elements of the writing carriage are mounted to the block by screw holes (not shown) in the block.

FIG. 2H is a plan view of a writing table (33) generally used in various embodiments of circuit lighters, showing elements not found in other figures. The writing table is pivotally mounted on a pivot pin (571) firmly attached to the base plate (15). The lower part (573) of the writing table has three wheels (575,577,579) mounted on the part (573) and rolling on the upper surface of the foundation (15). The writing table can be rotated relative to the foundation about a center of a pivot pin approximately in the center of the writing table in a desired manner. The wheels are responsible for the weight of the table. Minimal mechanical clearance, typically 1/2 mil for table mounting on pivot pin and wheel mounting on table
(12.7μ), the pivot pin (57
1) Almost no movement of the table other than rotation around can occur.

A bracket (581) is secured to one of the corners of the table (33) as an actuating arm for controlling the rotational position relative to the foundation and other circuit lighter elements. Another bracket (583) is attached to the foundation (15) and holds the linear actuator (585). The shaft (587) of the linear actuator extends and contracts in the direction of the arrow (589) and has a spherical end cap (591). Bracket at one end (581)
In addition, a tension spring (593) having the other end attached to the bracket (583) always biases the table bracket against the actuator shaft. The linear actuator (585) is operated via a computerized control system (43),
Write table in a relatively small arc, typically 5
°, used to rotate. This is used in the alignment (centering) procedure after the blank has been installed on the writing table and before the circuit writing has begun.

One way in which a PCB blank can be fixed to a writing table for writing circuits is a vacuum. In a preferred embodiment, the upper portion of the writing table is a vacuum chuck. In Figure 2H, many small holes (59
5) can be seen. Holes are shown only over a small area of the top surface to avoid obscuring other details, but in a real device there would be a similar hole almost all over the top surface of the writing table where the blank PCB might come into contact. To do. The holes are internally connected, resulting in a pipe fitting (597) leading to a vacuum device (not shown in Figure 2H).
A typical way to provide these holes on the top of the writing table is to use a sintered metal ball on the surface of the writing table. Although it was possible to use only a vacuum as the plate holding mechanism, such a way is to use a PC.
B-blanks would typically have holes for mounting elements, which would have been very noisy. Thus, in a preferred embodiment, a piece of tape, such as that typically used in the semiconductor industry (ie, a tape that leaves no residue when removed) is placed over the top surface of the writing table and taped in a vacuum. Hold firmly. Then place it on top of the PCB blank tape and hold the blank by the adhesiveness of the tape.

The method of moving the write carriage (23) in the y-direction in the preferred embodiment is shown in FIGS. 3A and 3B. First
In Fig. 3A, rail assembly (11,13), installation block (69,71), column (93,95), upper cross rail shaft (8
5) and the writing carriage (23) are all drawn with dashed lines. Four relatively large stanchions (131, 133, 135, 137) are securely attached to the base plate (15) by conventional fasteners (not shown). The frame post acts as an anchor that anchors the drum drive cable to the frame that performs both x and y movements.

FIG. 3B, which is a cross-sectional view of plane 3B-3B of FIG. 3A, shows the first and second stanchions (131, 133) in a three-dimensional plane, with the arrangement of the various elements of the cable mechanism performing the y movement.

Power to move the write carriage in the y direction is driven by the drive (3
1) which includes a step motor (second electric motor) (139), a framework (141) and a second cable drum (143). FIG. 3A shows the y drive section (31) in a plan view. FIG. 3C, which is a cross-sectional view taken along the line BB of FIG. 3A, shows the y drive section (31) in a three-dimensional plane. The second cable drum (143)
Is pivotally mounted between the two upstanding portions of the framework (141) and is driven from one end by the output shaft of the second motor (139). The framework (141) is securely attached to the foundation (15) by fasteners (not shown).

According to a preferred embodiment, the actuation of the y drive involves two strong, braided steel cables. 6th cable (14
7) is fastened to the end close to the motor, starts there, and is wound around the second cable drum (143), and exits the drum from the lower side, and the fourth frame pillar (135) and the third frame pillar ( 137) toward the side. The winding around the drum is single and each winding around the drum is adjacent to the next winding. Figure 3D shows
FIG. 3C is a sectional view of the cable drum (143) taken along line 3D-3D of FIG. 3C, showing the sixth cable (147) emerging from the underside of the drum. The fifth cable (145) is wound around the cable drum (143) starting at the end opposite to the motor connection,
This also comes out from the lower side of the drum, but goes out in the direction opposite to the sixth cable (147) toward the frame pillar (131, 133) side. FIG. 3E is a sectional view taken along the line 3E-3E in FIG. 3C, showing the fifth cable (145) exiting the drum.

Since the cable is wound on the drum only once and the two cables are wound on the drum in opposite directions of rotation, rotation of the drum in one direction winds one cable on the drum and the other Feed the cable the same amount out of the drum. Turning the drum clockwise as viewed toward the motor of Figure 3D causes the sixth cable (147) to be unwound from the drum and the fifth cable (145) to be wound around the drum by the same amount.

The fifth cable (145) extends from the drum (143) to the bearing support pulley (149) where it bends 90 ° and the second frame post (13).
Go to 3). The positions of the pulleys and cables are shown in plan view in FIG. 3A. FIG. 3B (section 3B-3B in FIG. 3A) shows a pulley (149) installed on top of a rigid support (151) firmly installed on a base plate (15). FIG. 3B is divided into four parts, and the total length of the circuit lighter can be represented by one sheet.

The second frame pillar (133) has two pulleys, that is, the pulleys (153).
And pulleys (155), which are similar to pulleys (149), but which make the plane of the pulley vertical so that it acts as a stable mooring point and at the same time changes the height and direction of the fifth cable (145). Are arranged. The fifth cable (145) is a pulley (15
3,155) and above the foundation plate, at a height just above the top surface of the mounting block (69) riding on the first saddle carriage (17) and extending horizontally back in the x direction. Two pulleys on the mounting block (69), namely pulleys (157,
159), which are arranged substantially side by side in the horizontal plane. The position of these two pulleys on the block (69) relative to the other elements is shown in elevation in Figure 2G.

The fifth cable (145) from the pulley (155) is the pulley (15
Turn 90 degrees around 7) and extend in the y-direction towards the writing carriage (23) through the hole (161) in the strut saddle (163) (similar to the strut saddle (97)). The writing carriage base block (119) has a pulley (165) installed below it in a horizontal plane at the same height as the pulleys (157,159). The cable (145) goes around this pulley 180 ° and extends in the y-direction towards the mounting block (69) and through the second hole (167) in the strut saddle (163) and through the pulley (15).
Turn 9) 90 ° and extend toward the first frame column (131). At the first frame post (131), the cable (145) is firmly anchored to the anchor pin (169) that extends through a portion of the frame post. The pin (169) is threaded and the nut (1
71) is included, when the nut (171) is rotated, the fifth cable (145) is pulled, and when the nut is loosened, the fifth cable (145) is pulled.
Give slack to the cable (145). 5th cable (14
Since 5) is locked to the second cable drum (143), tightening the nut (171) applies tension to the cable.

The sixth cable which is locked to the drum (143) at the end of the second cable drum (143) opposite to the fifth cable (145).
The cable (147) was installed from the drum to a support similar to the support (151) attached to the foundation plate (15),
It extends to a pulley (173) similar to the pulley (149). The sixth cable (147) turns 90 degrees around the pulley (173) and extends toward the fourth frame column (135). At the 4th frame pillar (135),
The sixth cable (147) goes around the pulleys (175,177) and extends back towards the second saddle carriage (19) where it turns 90 ° around the pulleys (179) to the strut saddle ( Pull the pulley (16) through the hole (181) (Fig. 2D) in 97).
Near the 5), extend to the pulley (183) installed under the writing carriage (23). The pulley (165) and the pulley (183) are firmly installed in the base block (110) which forms the basis of the writing carriage (23).

The sixth cable (147) turns around the pulley (183) by 180 °, returns toward the installation block (71), and passes through the hole (185) of the column saddle (97). Cables pulleys (187)
Turn around 90 degrees and extend to the third frame pillar (137),
It is firmly attached to the anchor pin (189) for locking the sixth cable (147) by the third frame pillar (137). The anchor pin (189) has a nut (191) used to adjust the tension of the cable system.

The clockwise rotation of the second cable drum (143) (Fig. 3D) causes the fifth cable (145) to wind around the drum,
Pull out the cable (147) from the drum by exactly the same amount. This operation is performed by the second cable drum (143) and the first cable drum (143).
Shorten the total length of the fifth cable (145) in the mechanism of the pulley with the anchor (169) in the frame column (131), and between the drum and the anchor (189) in the third frame column (137). Lengthen the sixth cable (147) by the same amount. The drive assembly (31) and pulley (14) as well as all four frame posts.
Since 9) and (178) are all firmly mounted on the base plate (15), the distance between the drive assembly (31) and each pulley (149,178) is unchanged. The only location where dimensional changes can be accommodated is the location of the write carriage (23), which is supported by the ball bushing so that it can move along the crossrail assembly.

Rotating the second cable drum (143) clockwise reduces the effective length of the fifth cable (145) and moves the write carriage (23) towards the x-direction rail assembly (11). Specifically, write carriage (23)
Moves a distance equal to one-half of the shortened dimension of the cable. For example, if the drum is rotated a sufficient amount to reduce the effective length of the fifth cable (145) by 4 cm, the write carriage (23) will move 2 cm. This rotation adds 4 cm to the effective length of the sixth cable (147) so that the write carriage (23) is not constrained by the sixth cable (147) around the pulley (183).

Because of the precise movement required for circuit writing, play or dimensional instability can cause serious errors in making circuit connections. Thus, in the preferred embodiment, this dimensional instability is typically limited to ± 2 mils (50.8μ). Thus, the adjustable anchor pin is used to preload the cable to a tension near (not equal to) the elastic limit of the cable. Moreover, the cable is moved and stressed prior to installation to eliminate small kinks. Both of these operations eliminate the plastic or non-linear elastic deformation of the cable during operation and substantially all play. Another important outcome of the cable arrangement on the drum is that the elastic deformation on one side of the device is precisely balanced by an equal amount of elastic deformation on the other side. For example, in a y-direction cable assembly, the fifth and sixth cables (145,14
The angle formed by each of 7) and the rotation axis of the second cable drum (143) is such that the writing carriage (23) is at the center of its travel limit during operation, that is, the saddle carriage (17) and the saddle carriage (19). It becomes 90 ° only at some point in the middle of. As the drum rotates, wind the fifth and sixth cables (145, 147) around the second cable drum (143),
The contact point where the two cables come into contact with the drum (that is, the cable leaves the drum,
The points that extend toward the pulleys (173,179)
Depending on the direction in which the drum is rotating, it will move together in either direction along the length of the drum. This movement of the contacts (or an equivalent change in the angle between the cable and the drum axis) results in tension and loosening of the cable. For example, by winding each cable from both ends of the drum, the contacts move together, and the contacts move in a pulley (173,
179) to ensure that each cable is pulled or loosened by a substantially equal amount as the drum rotates as it is substantially equidistant from 179) to ensure that the stresses in each cable match. Thus, the precise movement of the carriage assembly is directly related to the distance the cable has traveled and is not a function of stress in the cable.

The operation of the write carriage in the y direction is independent of the position of the cross rail assembly in the x direction. Rail assembly (1
The movement in the x direction along the 1,13) is the pulley (159,157,165,183,17
9,187) but does not affect the effective length of any y-direction cable (the length unwound on the drum).

The x-direction movement is accomplished by an x-drive (29) that is independent of the y-direction drive. FIG. 4A is a plan view of a drive similar to FIG. 3A, but the y-direction cable drive (31) is not shown. The x drive (29) shown is a motor-driven drum cable drive similar to the y drive (31), except that the first and second saddle carriages (17, It has a different cabling mechanism for moving the cross rail assembly in the x direction over the bearing associated with 19).

There are four cable extensions exiting the x drive (29) shown in Figure 4A. The plan view of the x-drive of FIG. 4A of the four extensions of the first and second cables (199,205), the third and fourth cables (201,203) is implicit, the winding of the cable on the drum. No details of attachment are shown. FIG. 4B is an enlarged plan view of the x driver (29) showing the elements and cable arrangement in more detail. The x-drive (29) has a mounting bracket (195), a first cable drum (197), and a first drive motor (first electric motor) (193) for rotating the drum. The first cable (199) is connected to the first cable drum (1
It is wound from the motor side end of 97) and goes out from the upper part of the drum to one side. The fourth cable (203) is the first cable (1
Contrary to the winding of 99), it is wound from the end of the drum farther from the motor and goes out from the upper part of the drum on the side opposite to the direction of the first cable (199).

The second and third cables (205,201) are shown to be one cable wound on the drum between the first and fourth cables (199,203), but both ends thereof emerge from the lower part of the drum in opposite directions. The extension of the second cable (205) is in the same direction as the first cable (199), and the third cable (201)
The extension of is in the same direction as the fourth cable (203). For convenience of description, two extensions of one central cable are treated as two cables, and are referred to as a second cable (205) and a third cable (201).

FIG. 4C is a sectional view taken along line 4C-4C of FIG. 4B, showing the first cable (199) extending from the first cable drum (197) to one side.
Indicates. FIG. 4D is a sectional view taken along line 4D-4D of FIG. 4B and shows the second cable (205) and the third cable (201) in addition to the first cable (199). FIG. 4E is a sectional view taken along line 4E-4E of FIG. 4B, showing the fourth cable (203) along with other cables. In Fig. 4E, clockwise rotation of the first cable drum (197) extends the first cable (199) to one side,
Extend the third cable (201) to the other side and
Take up the cable (205) and the fourth cable (203).

Referring to FIG. 4A, the third cable (201) is the third,
It extends to the side of the fourth frame pillar, reaches the pulley (207) attached to the pillar (255) installed on the base plate (15), and further extends to the third frame pillar (137). In the third frame pillar (137),
The third cable (201) passes around the two pulleys (215, 213) and changes direction and height. The third cable (201) then extends towards the mounting block (71). These elements and mechanisms are also shown in Figure 4F, which is an elevational view from the 4F-4F side of Figure 4A, and is also a perspective view looking toward the third frame post (137), 4G. Also shown in the figure. It may be helpful to refer to each of the other figures to understand the relationships.

In the installation block (71), the third cable (20
1) rotate 180 ° around the pulley (219),
Return to 37) and turn around the pulley (211) to the mounting block (7
Return to 1). In the installation block, the third cable (2
01) is mounted next to a pulley (219), but goes around another independently rotating pulley (220).
The third cable (201) then returns to the third frame post (137),
There, it is connected to a cable anchor (217) which can be adjusted by means of a nut (218). Third frame pillar (13
Third cable (201) between 7) and installation block (71)
Is "passed" four times. As a result, the third cable (201)
4 cm on the drum (197) and install the installation block (7
1) will be moved 1 cm.

The fourth cable (203) extends to the same side of the third and fourth frame columns as the third cable (201), and the pulley (20) on the column (257).
9) around the fourth frame pillar (13) on the same side as the third frame pillar (137)
Reach 5). FIG. 4H is a perspective view showing these mechanisms as seen toward the fourth frame pillar (135). Fourth frame pillar (13
In 5), the fourth cable (203) is the pulley (227,225)
Rotate to change the height and direction and extend toward the mounting block (71). In the mounting block (71), the fourth cable (203) goes around the pulley (221), returns to the fourth frame pillar (135), turns around the pulley (223) and returns to the installation block (71), and then the pulley (221). Rotate the pulleys (222) that are adjacent to each other but rotate separately, and again the fourth frame pillar (135)
, Where it is locked to the cable anchor (229). When the first cable drum (197) rotates in one direction, the third cable (201) extends, while the fourth cable (203) is contracted by an equal amount to move the installation block (71) in one direction. Energize. Rotating the cable drum in the opposite direction has the opposite effect and moves the mounting block in the opposite direction.

The first and second cables (199, 205) extend on the side of the frame column opposite to the third and fourth cables (201, 203) (4A
Figure), moving the installation block (69) in synchronism with the installation block (71) to move the cross rail assembly smoothly in the x direction along the x rail assembly (11, 13). The first cable (199) terminates at the anchor (241) using a pulley (231,235,237,243,239,244). Second cable (2
05) uses pulleys (233,247,249,245,251,246)
It ends in the anchor (253) of the second frame pillar (133). When the first cable drum (197) is rotated in one direction, the first and third
The cables (199, 201) are contracted, while the second and fourth cables (205, 203) are extended by the same amount to urge the cross rail assembly toward the first and third frame columns (131, 137).
Rotation in the opposite direction urges the crossrail assembly in the other direction. The cable anchor can be adjusted to tension the cable to remove small kink and pre-tension the cable to near the elastic limit to eliminate displacement due to cable strain. In this preferred embodiment, both the y-drive motor (139) and the x-drive motor are D
A C step motor is desirable. It will also be apparent to those skilled in the art that high resolution servomotors or other electric motors with high resolution may be used. In the preferred embodiment, operation of these motors is controlled by a computer controlled system (4
3) Controlled by (Fig. 1), are the control systems as if they were synchronized to give a very precise movement, without the strain on the computer equipment that normally occurs during microstepping? Drive these DC step motors like. Such directions are also quieter than many other ways. Two
The electric motors are independent of each other and are operated forward, backward, started, stopped, and operated at various speeds from 0 to about 5 rpm. The motor operates in response to a computer program generated from routing information for the trace on the printed circuit board to be produced. As mentioned above, the cable mechanism from the drive moves the cross rail assembly (21) in the x direction, along the rail assembly (11, 13), and the write carriage (23) in the y direction, crossing. Rail assembly (21)
Move along. The coordinated movement of the two drives is 2
The writing extension (37) is moved with two degrees of freedom above the writing table (33) in such a manner that a three-dimensional pattern is written with a pencil or a pen.

FIG. 5 shows an example of a simple geometric figure, assuming that the circuit writer is required to trace on the PCB to write. Traces (259) represent conductive traces provided by the writing extensions (37) (not shown). The arrow (263) indicates the x direction, and the + and-signs indicate any forward and backward arrangement in the x direction. The arrow (261) represents the y-direction, and the + and-signs indicate arbitrary forward and backward arrangements in the y-direction.

Starting at point (265), trace (259) extends along section (269) at an angle of about 45 ° to the x, y directions.
To explain the operation of the circuit lighter, trace (25
Suppose 9) is written from point (265) to point (297). Portion (267) is written by rotating the x and y drives to move the write carriage in the x direction and the write carriage in the y direction at the same rate. Beginning at point (269), the y drive is slower than the x drive, and at point (273) the y drive is stopped and only the x drive is rotating. As a result, a curved portion (271) is formed. The curvature is adjusted by controlling the relative drive speed. Portion (275) is a straight line extending in the + x direction and is delineated by rotating only the x drive. At point (277), the y drive begins to operate again. At the curved portion (279) extending to the point (281), x
The speed of the drive decreases with a harmonic function, while the speed of the y drive increases with the same harmonic function, which is out of phase with the function of the x drive by a phase angle of 180 °. As a result, a 90 ° arc is generated, the x drive stops at point (281), and the y drive operates in the y direction.

The portion of the trace (283) results from the rotation of the y drive and the rest of the x drive. In this part of the trace, there is no movement in the x direction. At the point (285), the x-direction drive section is restarted, the x-direction velocity increases with the harmonic function to reach the point (287), and then decreases with the same harmonic function to the point (28).
Stop again at 9). During this time, the speed of the y drive unit is + y
It decreases in the direction to the point (287), and then increases in the -y direction to the point (289). The result is similar to the arc (279), but with the addition of an additional 90 °, the point (28
It is a 180 ° arc from point 5) to point (289). At point (289) the y drive is operating in the -y direction and the x drive is stopped, producing a vertical section from point (289) to point (291). At point (291), the speed of the x drive increases with the harmonic function and the speed of the y drive decreases with the same harmonic function, but another arc is generated in the same way as the other arcs, and it is 90 °.
Produces an arc. Portion (295) is the straight line portion to point (297) that occurred when the x drive actuated in the + x direction and the y drive stopped.

Computer control of the x-drive and y-drive stepper motors in response to pre-programmed information regarding the position and size of the desired trace allows the circuit writer to generate the desired trace. The illustrated pre-tensioned cable arrangement allows the xy information to be accurately transmitted to the PCB. Traces can be generated with constant and variable curvature at any angle with respect to the x, y directions.

However, in practice, to avoid process control and automatic determination of routing paths for various traces, long trailing arcs are avoided and long movements at angles not parallel to the x, y axes of the device, for example 45 °. It has been found that it is generally preferable to avoid running lines. By allowing only certain movements in the computer program to determine the optimum progression of the trace to be written, such traces are avoided. Later, when describing the software control of the device, this program will be discussed, and this program is hereinafter referred to as "router".

FIG. 6A is a side view of the write carriage (23).
2E shows a cross section through the cross rail assembly adjacent to the write carriage in the same direction as in FIG. 2E. The elements of the bearing / spacer assembly that support the base block (119) in the y-direction along the cross rail assembly are not shown in FIG. 6A. The mounting plate (277,279,281,282) is firmly coupled to the base block (119) to form the structure on which the other elements of the writing carriage are mounted. The particular arrangement of the plates forming the mounting structure is not critical as long as the various elements can be mounted in the correct mechanical orientation. Thus, there are many other ways in which the mounting structure can be formed.

A clamp bracket (283) fixed to the writing carriage holds the rotary three-way valve in a substantially vertical orientation, with a material tank (35) mounted by a hermetic seal in an opening leading to the valve. The tank (35) contains uncured PTF material suitable for forming traces on the PCB. As mentioned above, in some cases this material is a conductive material, in other cases it is an electrically insulating material. The step motor (287) actuates the rotary valve (285) to start and stop the flow of material. Semi-rigid tubing (291), such as stainless steel tubing, extends from the lower opening of the valve (285) to the writing tip (293). While the step motor (295) raises and lowers the write chip (293) at the beginning and end of the trace on the PCB, P
Maintain the subtle height of the writing tip above the CB surface.

FIG. 6B shows an elevation view taken from the line 6B-6B in FIG. 6A and oriented 90 ° to the view in FIG. 6A. The clamping element that holds the valve (285) is part of a bracket (297) mounted to the plate (281). The bracket (297) has a fitting (29
The motor (28) that operates the rotary shaft of the valve (285) via the (9)
7) also plays a role of installing. A motor (295) is mounted on the frame by a bracket (301). This motor drives the spindle (30) that encloses the tongue of the tongue strip (305).
3) The writing chip is given a z-direction (vertical) motion by rotating. Tongue strips are bolted to slides (307) that are vertically guided in a pair of bearing guides (309).

Piping that passes through the uncured PTF material on the way to the PCB (29
1) creates some refraction and a wide bend between the valve (285) and the heater block (313) that is forced to pass the material through before reaching the writing tip (293).
The purpose of refraction and bending is to provide the writing tip with the required degree of freedom of movement while maintaining a steady flow of material.
There are other forms of piping, such as loops, that can be used to provide the required mechanical freedom. However, it is generally desirable to keep the length of the PTF passage relatively short.

The purpose of the heater block (313) is to keep the uncured material at a known temperature in order to control the viscosity.
The heater block (313) is resistively heated by an electric current, and the temperature measurement of the block should preferably be
Feedback is provided to a computerized control system (43) (not shown in FIG. 6B) by a thermocouple element in (not shown in FIG. 6B). The control system maintains the temperature according to a pre-programmed set point. The temperature of the material flowing through the writing tip is typically the desired PTF used.
It is controlled at 40 ° C. for the materials (described below), but can be at different temperatures depending on the physical properties of the particular trace material being extruded.

Figure 6C is along one edge of slide (307), 6C in Figure 6B.
Shows the −6C plane. The spindle (303) has a tongue strip (3
Tongue-like strips that extend inside the loop of 05) (305)
Are coupled to the slide (307). FIG. 6D is a perspective view of only the tongue strip (305). Tongue strip (30
5) is used to connect linear motion elements to rotary motion elements so that rotation can be converted to linear motion without play. It is also very important that the play is 0 (zero) for z drive. This is because controlling the height of the write chip above the PCB while writing a trace is important because it allows you to complete high quality traces and have traces that cross over other traces. is there.

The resistance heater (313) is coupled to the slide (307) at the bottom end of the slide, and the writing tip (293) is fixed to the resistance heater. With this mechanism, precise rotation of the spindle (303) gives a precise vertical movement of the writing tip (293), and by repeating the step position of the motor (295), this movement is repeatable without mechanical hysteresis. Become.

FIG. 6E shows a BB cross section through the valve (285) of FIG. 6B. The valve has a body (317) having an upper passage (321) and a lower passage (323) each having a diameter approximately equal to the inner diameter of the pipe (291). The valve body has a cylindrical central hole into which a closely fitted central drum (319) fits. Drums (319)
Is rotatable in the valve body and has a joint (299) (Fig. 6B)
It is rotated by a motor (287) via. The central drum has a direct passage (325) and a side connecting passage (327). First
At the position shown in Fig. 6E, the direct passage (325) is the passage (321, 32
Match 3). This is the position the valve maintains for sending PTFs during trace writing.

For illustration purposes, rotation of the drum (319) from the position of Figure 6E to "close" the valve is counterclockwise. Due to the smaller diameter of the passage relative to the diameter of the drum, the passage (32
Since 3) is typically more than 100 times the cross-sectional area of the outlet orifice of the writing tip, only a slight rotation is required to completely block the flow of material. Therefore,
The flow is very fast and can typically be stopped in less than 500 microseconds. As a practical matter, in order to obtain an accurate trace, it is attempted to stop the flow at a time of at most 1 millisecond. In the illustrated embodiment, when closed, the drum rotates 90 ° to the position shown in Figure 6F, with the side passageway (327) coincident with the exit hole (323). The valve (285) is typically a brass valve covered with stainless steel,
This valve is often used in hospital environments. An example of such a valve is part number 6011 or 6014, which can be purchased from Poper & Sons.

In FIG. 6A, the elements are shown with one tank for writing traces in either conductive or non-conductive PTF material. Figure 6A shows a plate (281) forming part of a write carriage structure extending outwardly from both sides of the write carriage (23). In fact, a second assembly of elements can be added on the side of the writing carriage opposite the first assembly and attached to the plate (277) to write traces on two different materials. .

In operation, an inert gas such as nitrogen is used in the line (28
9) Uncured PTF in tank (35) introduced via
A gas pressure is created above the material. The gas introduced is from a source (not shown) outside the circuit lighter and the pressure is typically 25-55 psi (1.76-3.87 kg / cm ² ). When not writing, the valve (285) is closed,
The writing chip (293) is above the surface of the PCB blank, approximately
Lifted by z-drive to 1 cm point.
To write a trace, move the writing chip over the place where the trace should start on the PCB, just like the x drive and y.
Activate the drive. Next, the z-direction drive is actuated to move the write tip close to the PCB surface.

Two different writing chips are used to operate the circuit writer, one for writing conductive PTF traces and one for writing isolated PTF traces. Typically, but not always, overlaid on conductive PTF traces. FIG. 6G shows a typical structure of the writing chip. A cut section (601) of stainless steel, standard wall thickness, 010 ″ (0.254 mm), 26 gauge hypodermic tubing is fixedly attached to the fitting (603). In a preferred embodiment, a bore is provided in the inner diameter of the fitting. There is (606),
This matches the relatively steeper region of decreasing diameter (604), which in turn becomes the second region (602) of decreasing diameter at a relatively shallower angle than region (604). Fits. Region (602) reduces in diameter to the inside diameter of tube (601). The tube (601) is inserted until it hits the shoulder so that there is no sudden obstruction to the flow of material into the tube (601). The length of the tube (601) is generally an important consideration in controlling PTF flow, as it is related to the back pressure it creates. For example, Becton-Dichso
n) Manufacturing of Leur-Loc female joint N
o.462 LNR, stylet unindexed fittings (60
3) The length S1 of the tube (601) is typically 0.200in (5.0
8 mm). Clearly, there are other fittings that may be suitable, and special fittings can also be machined.

FIG. 6H is an enlarged view of the end of the hypodermic tube enclosed by the circle (605) in FIG. 6G. This is a treatment of the tip used to write the first trace of conductive PTF material, with an outer bevel A1 of about 30 degrees processed into a hypodermic tube. The bevel is not cut until it produces a sharp edge with the inside diameter of the tube. This is because sharp edges are fragile and are susceptible to erosion and damage. A land S2 of about 1 mil (25.4μ) is typically provided. At that time, the diameter S3 is about 12 mil (305μ). Figure 6J shows how the outer beveled tip of Figure 6H relates to the PCB surface when writing traces. The width S3 in Figure 6H is a controlling factor in the formation of the trace (605) in Figure 6J, and the chip height H1 above the PCB surface (607) is about 0.5 of the chip width S3.
Is kept double. In this case, H1 is about 6 mil (152μ). However, in practice, in the desired range of viscosities and flow rates, as well as the desired PTF prescription, trace width is largely independent of needle height and there is no apparent change in trace width with about -100 to + 50% change. There is no relative insensitivity to this hand height, which is very important in being able to give well-defined, high-density traces.

FIG. 6I is a different cutting process for the edge of a hypodermic injection tip. In this case, the inner bevel was cut into the tip of a tube having the same specifications as the tip of FIG. 6H. Interior angle A2 is about 118 °
Is. This is also about 1mil (2
5.4μ) land is left. Where S4 is the outer diameter of the 26 gauge tube, which is about 18 mils (457μ). FIG. 6K shows how an inner beveled tip can be used to write a trace of insulating PTF (609) over a trace (605) of conductive PTF material that has already been scribed. As a general rule, the dimension that controls the trace width is the effective outer diameter of the tube, ie the diameter S3 at the outer bevel is the effective outer diameter of the tube for the extruded PTF. Similarly, for the inner slope, diameter S4 is the effective outer diameter of the tube for the PTF being extruded.

To begin the trace writing, open the valve (285) to allow the PTF material to flow to the writing tip, actuate the x and y drivers and pre-programmed into the computerized control system (43). Write to the desired trace pattern and move the carriage through the associated cable mechanism. During the trace writing, the resistance heater (313) is activated to keep the PTF material flowing to the writing tip at a constant temperature. The temperature is preprogrammed according to variables such as those required for the particular PTF material used, the writing tip and the width and thickness dimensions required for the trace.

A typical "writing height" of the trace is 5 to 5 depending on the specific effective diameter of the exit end of the writing tip used.
It varies within the range of 10 mil (127 to 254μ). The surface of the PCB on which the trace is to be written is likely to vary by more than this amount. As a result, if the Z drive is stopped,
Therefore, if the trace were written with the write chip at a constant height, the height of the write chip relative to the surface of the PCB would change unacceptably. To prevent this problem, first measure the height of the PCB surface with respect to the circuit lighter frame reference plane. Divide the PCB into 3 cm square areas and determine the standard height for each area. It has been found that the height in such an area does not change significantly enough to affect the operation of the circuit lighter. This information is input to the computer of the control system and the relation with the position of the trace on the surface of the PCB is expressed. Then, during the trace writing, the z drive is operated to change the writing height taking into account the area where the writing is currently taking place.

At the end of the trace, valve (285) is closed to prevent further extrusion of PTF material from the write tip. The inner drum of the valve rotates 90 ° in about 18 ms. However, as previously mentioned, only a few degrees of rotation are needed to completely close the passage in the valve, so that the flow is effectively blocked in a time period much shorter than 1 millisecond. When the valve drum rotates 90 °, the side passage (327) coincides with the lower hole (323) and the passage (325) coincides with the opening (329) of the valve body.
As a result, the entire passageway (291) of the pipe leading up to the writing tip is opened to atmospheric pressure, reducing the pressure provided by the inert gas source in the tank, so that it remains after closing the valve. The continuation of the extrusion of PTF material from the writing tip by pressure is cut off. At the end of the trace writing,
The z-direction drive operates so as to lift the writing chip as well.

FIG. 7A shows a preferred alternative circuit writer (hereinafter referred to as type 2). The difference between the first preferred embodiment and the Type 2 is that both the x and y direction drive bearing rails, the x and y direction drive sheave arrangements, and the two writing assemblies on the same carriage. The orientation of the carriage element, for writing.

Write carriage (337), as shown in Figure 7A.
Rides on the y-direction rail assembly (335), and the y-direction rail assembly is installed on the installation block (339, 341) like the cross rail assembly of the previous embodiment. The mounting block (339) rides on the x-direction rail assembly (331) and the mounting block (341) rides on the x-direction rail assembly (333).
Since the mounting block and y-direction rail assembly are non-flexible assemblies, the y-direction rail assembly is constrained to move in the x-direction along a set of x-direction rails.

FIG. 7B is a cross-section taken along line 7B-7B of FIG. 7A through the x-direction rail assembly (331) adjacent to the mounting block (339). The bearing mechanism of the x-direction rail assembly (331) includes a rail (347), which is named Schnee burger rail in the name of the company from which it can be purchased. Two bearing blocks (349,35) associated with the Schnaberger rail
There is also 1). The bearing block is attached to the spacer plate (353), which serves to hold the block in place with respect to the rail. Each bearing block has complementary ball bearings that circulate in a circulation passage within a restraint rail within the block. As is known to those skilled in the art, the mechanism that produces this result provides a play-free, low-friction bearing rail mechanism that has a special load bearing capability in the horizontal direction perpendicular to the x-direction.

The schneberger rail is above the foundation (343),
It is supported on a long support block (345) and is joined to the block by conventional fasteners. The mounting block (339) is firmly connected to the spacer plate (353) and the support material (359) is connected to the mounting block. Support material (35
9) carries the second Schneberger rail. Rails (357) provide a rail for restraining the cross rail assembly for movement in the y direction, which is at 90 ° to the x direction. Rail assembly (333) is rail assembly (331)
Includes elements equivalent to those shown for.

FIG. 7C shows 7C- of FIG. 7A through the cross rail assembly.
It is a figure of 7C surface. The schnaberger rail (357) is shown in cross section. The spacer plate (361) replaces the bearing block (3
Blocks to constrain the write carriage to move in the y direction along the cross rail assembly, similar to the assembly of equivalent elements of the rail assembly (63,365). Hold.

The spacer plate (361) also serves as a mounting base for assembling the elements for delivering the conductive or non-conductive PTF material, which elements, along with the spacer plate and the bearing block (363,365), are written in the carriage (337). Make up. The feed and write tip positioning assembly of the 2-inch embodiment is the first described above.
Of the equivalent assembly of the preferred embodiment of Similar to the first embodiment, two such assemblies can be used so that conductive and non-conductive traces can be routed. However, unlike the first embodiment, the PTF
The two assemblies for feeding material and controlling the writing height of each writing tip are mounted side by side rather than on either side of the cross rail assembly as in the first embodiment.

FIG. 7D shows the write carriage (337) taken along line 7D-7D of FIG. 7C and illustrates two PTF material feed assemblies. The construction and installation of the two assemblies are mirror images of each other and the writing chips (369,371) are in close proximity.
If you are writing one circuit on the other side of the writing chip,
This scheme has the advantage that, if one wishes to change to the other chip, bringing the second chip to the position of the first chip requires only a minimum movement of the write carriage. For example, if one circuit were written with traces of two different widths, it would be desirable to change from one chip to the other. Such a change would also be desirable if the circuit required both conductive and non-conductive traces.

Also in the type 2 embodiment, there are separate cable drives for the x-direction movement and the y-direction movement, just as in the first embodiment. The y-direction cable system for moving the write carriage along the crossrail assembly is quite similar in both embodiments. The cable drive part (373) has two cables wound from both ends of the drum. The cable (375) exits from the top of the drum, crosses the pulley system to the second frame post (377), then to the pulley on the installation block (339), and then the pulley below the writing carriage to 180. It turns back to the mounting block (339) and finally is attached to the adjustable anchor point (379) on the first frame column (381), exactly as in the first embodiment. The cable (383) exits from the bottom of the drum and crosses the similar pulley system on the opposite side of the circuit lighter to the 4th frame post (38).
5) Go to the installation block (341), go through the pulley under the writing carriage and return to the installation block (341), and finally to the adjustable anchor (3) of the third frame column (389).
Reach 87). Actuation of the y-drive drum with a stepper motor moves the write carriage back and forth along the schnaberger rails of the cross rail assembly.

In some cases, it may be desirable for the y-drive to have two cables on one side instead of one, as shown in FIGS. 4B, 4C,
By winding a third cable around the center of the cable drum of the drive (373) in a manner similar to the cable mechanism described above for the x drive of the first embodiment illustrated by FIG. 4D. Be seen. The third cable provides another cable extension on each side and a supplementary pulley so that the new cable extensions on each side closely follow the original single cable path. I do. in this case,
An additional anchor is required for each of the first and third stanchions (381,389). Giving such a dual mechanism to the y-drive strengthens the mechanism, as there are now two cable runs between each once-one point.

The x-direction driver for the Type 2 embodiment is somewhat different than the x-direction driver of the first embodiment. x drive unit (391)
Also includes a motorized cable drum. Two cables are wound around the drum. The cable (393) is a single winding from one end of the drum (away from the motor end),
It goes out from the lower side of the drum and extends toward the third frame pillar (389). The cable (393) extends around the sheaves (394) in the sheave mounting bridge (396) to the third frame post (389) and through the vertically oriented sheaves to the mounting block (341). In this installation block, the cable (393) goes around the pulley (397), returns to the third frame column (389), and goes around the pulley (395). The cable then returns to the mounting block (341) and the pulley (3
97), but pulleys (39
Go around the 8) back to the 3rd frame post (389) where it is attached to the adjustable anchor (399). The rotation of the cable drum, which winds up the cable (393), is carried by the mounting block (341).
Is urged toward the third frame pillar (389). The groove on the top of the pulley (395) is the pulley (397) in the mounting block (341).
The pulley (395) is angularly attached to the frame post so that it is offset from the lower groove by an amount equal to the distance between the groove in the groove and the groove in the pulley (398). This attachment allows the cable to move straight in and out of the sheave groove, reducing friction effects, especially when the cable is under strong tension, as in the desired mode of operation.

FIG. 7E taken along line 7E-7E of FIG. 7A shows only three pulleys illustrating the relationship between the two pulleys on the mounting block and the diagonal mounting pulleys of the frame columns.

The cable (401) is wound around the cable drum from the side closest to the motor drive side, and emerges from the lower side of the drum toward the first frame column (381). The cable (401) goes around the pulley (405) attached to the block close to the first frame pillar (381) and extends to the entire length of the circuit lighter to the second frame pillar (377).
go to. In this second frame pillar (377), the cable (401) goes around the vertically oriented pulley to the installation block (339), and then around the pulley at the installation block to the second frame pillar (37).
Returning to 7), go around the obliquely mounted pulley to the mounting block (339), around the second independent pulley there and back to the second frame post (377), where it joins the anchor. This mechanism is similar to that of the pulley and cable system between the mounting block (341) for the cable (393) and the third frame post (389). x Drive cable As the drum turns around and winds up the cable (401), the installation block (3
39) is urged toward the second frame pillar (377).

Only two cables (393, 401) are wound on the drive drum and these two perform the drive. Third cable (40
7) passes over the drum, but it doesn't wind up on the drum.
The cable (407) extends on one side to the third frame post (389) and turns around a pulley (409) that is angularly attached to the pulley attachment bridge (396). From this point, the cable (407) extends the entire length of the circuit lighter and goes to the fourth frame post (385). The cable (407) passes around the pulley and between the fourth frame post (385) and the mounting block (341) in a manner similar to that described for the cables (393, 401). On the opposite side of the circuit lighter, the cable (407) extends to the first frame post (381), around the pulley and the first frame post (38) in the manner already described for the other pulleys.
Pass between 1) and the installation block (339). The cable (407) is locked to the first and fourth frame columns (381, 385) and acts as an idler assembly that balances the tension of the mechanism of the cables (393, 401).

Figure 7F is taken from the same end as line 7E-7E in Figure 7A, but towards the center of the circuit lighter. Cable (39
The drum of the drive (391), where 3) extends towards the pulley (394), the cable (401) extends to the opposite side, and the cable (407) extends over the drum to the diagonal pulley (409) on one side. Indicates. Pulleys (394,409) are both pulley mounting bridges (3
96) but the bridge is not shown in Figure 7F, so the pulley relationship looks better.

The pulley and cable mechanism for x-direction movement is such that when the drum of the drive (391) is rotated in one direction and in multiple directions, the cross rail assembly moves left and right along the x-direction rail assembly. ing. Turning the drum of the y drive (373) in one direction and the other moves the carriage along the cross rail assembly in the y direction moving back and forth. Therefore, by selectively turning the two driving units, a complicated pattern can be written by the writing chip on the printed circuit board arranged on the writing table (411).

The height of any of the writing chips in the type 2 embodiment is
It is controlled by a motor drive mechanism similar to that described in the first embodiment. The Type 2 embodiment has the advantage that it is lighter in weight than the first embodiment, but in part because of the fact that the Schneberger rail element is better than the rail element used in the first embodiment. It is light. Moreover, the Schneeberger rails are designed so that the forces generated by the pulling and movement of the cables are the bending forces over the long rectangular rails, giving a very rigid structure and ensuring dimensional stability . The arrangement and winding of the x-drive and the use of diagonally mounted sheaves also reduce the number of sheaves used. The use of angled pulleys enhances cable and pulley alignment and reduces drive friction.

Setup Means There is a sequence of setup procedures that must be followed in order to prepare a blank to be processed into a PCB by a circuit writer. The first step is to place the blank on a writing table, which can be done using a vacuum chuck and tape to hold the plate to the chuck, as described above. In each case, the blank must meet certain published standards and is visually installed in a specific location. Since circuit lighters operate with very close tolerances, visual alignment and placement of the board during setup is not sufficient to precisely trace the traces on the board.

The blank installed on the writing table cannot be perfectly horizontal, and to form the trace with the required accuracy, write at a precisely controlled height above the surface of the PCB on which the trace is written. It was pointed out earlier in this specification that the tip must move. Therefore, part of the setup procedure is to measure the height of the mounted blank surface relative to the circuit lighter frame at a number of locations in the matrix covering the blank area. This is done using a measurement probe mounted on the write carriage of the circuit writer. Element (630) of Figure 7A shows the LVDT measuring probe attached to the writing carriage. After initially positioning the measurement probe vertically and horizontally, the operator writes a keyboard command to a position in the matrix via a computerized control system and moves the carriage to move a large number of small areas (1 cm square each). The relative height at one point in each is read over the entire area of the blank into a computer, following the instructions of a measuring probe that contacts the surface of the installed blank, riding a writing carriage. This array of data is subsequently used for process control to control the height (z direction) of the writing tip relative to the surface of the blank on which the trace is written.

Alignment of the blanks in the x, y plane and in the rotational direction is accomplished by a video camera fixedly mounted on the write carriage of the circuit writer. For input to the computerized control system, the video camera projects a display for the operator containing a crosshair that allows the operator to match blanks and specific marks on the writing table. The element (629) in Figure 7A shows a video camera mounted on the writing carriage (337). A matching block is installed on the circuit writer to align the writing tip (also called a pen) with the crosshair of the camera and set it to zero. Since the control system "knows" the step position of each of the x, y, Z drive stepper motors, the cursor control keys on the computer keyboard are typically used to align each of the pen and camera crosshairs to the alignment block. By moving to the "standard" position of the and finding the position (putting it in the computer's database), the operator can create offset information for the computer. In the preferred embodiment, the operator is approached by the write carriage, approaching each reference point from the same direction, to reduce the problem of hysteresis that might otherwise introduce errors into the data. Care should be taken to match the closest step position (which is 1 mil (25μ) more).

The matching block, also known as the touchpad, is shown at element (70) in Figure 4A, which is mounted on the base plate of the circuit lighter. FIG. 4I is a perspective view of the alignment block as viewed in the direction of arrow (72) in FIG. 4A. The alignment block is carefully cut and mounted on the circuit writer's frame to provide an absolute position reference for the moving element. The worker uses this reference to move the pen, for example, to the surface (701,703,705) to create an absolute reference in the z direction,
Move to 9) to create an absolute reference in the y direction, and move to a parallel surface (711,713) to create an absolute reference in the x direction.

As part of the setup procedure, the operator also uses the camera crosshairs to enter the position of each of the three reference points in an orthogonal pattern on the PCB. Also in this case, care should be taken to approach the reference point at the closest possible step from the same direction. These points are put into the database,
Allow a computer program to calculate scale factors, offsets and rotation corrections. After the calculation, the writing table is rotated by the computer through the rotation mechanism shown in FIG. 2H, and the scale factor and the rotation angle are displayed. If the correction angle is relatively large, the operator may choose to repeat the alignment process. The alignment is typically repeated until the rotational correction is less than 0.001 °. The illumination during the alignment process is provided by a ring light, the purpose being to provide a homogeneous illumination that does not detract from the perception of the operator's landmarks. In the future, it is planned to use machine observation techniques on behalf of workers and to automate the alignment procedure.

Process control Since there are many equivalent elements between the two embodiments,
The control of the elements for implementing the circuit writing in the two embodiments is similar. Figures 8A, 8B and 8C are block diagrams showing the general requirements for converting raw data on a printed circuit board (PCB) design to a board on which traces are written by a circuit writer. Figure 8A is 3
Here are two big steps. Block (549) represents the computer-aided engineering (CAE) process of calculating the width and cross-sectional area required for the trace to carry the required load current with an appropriate safety margin. Blocks (551)
Shows a computer-aided design (CAD) process that performs tasks such as routing traces between various elements attached to a PCB. Block (55
3) is the CA sent to the circuit writer to have the x, y, Z drives and various actuators write traces on the PCB.
Information from process D is shown.

Figure 8B is a CAE showing the process of Schematic Capture (555) and Netlist Extraction (557) that yields a netlist (ie, a constituent table) to be used as input data for the CAD process. It is an enlarged view of a process.

Figure 8C shows the physical location data (559) and netlist sent to the routing engine (561) (router),
Shows how the router lays out the traces for the PCB, producing a database called routes,
It is an enlarged view of a CAD process. The number of trace connections allowed on one connector pad where the device is mounted on the circuit board, the minimum spacing between traces on the board (to avoid short circuits and other cross-space hazards), the minimum bending allowed The router operates according to programmed principles such as radius, and other items described below.

Various computer programs for implementing CAE and CAD are known to the parties and can be used to create the physical layout of the netlist and PCB. Similarly, routers are commercially available and can be used to create routes directly. However, the specific rules associated with this extrusion method that provides tracing are built into the command set.

FIG. 9 is a block diagram of process control for a circuit writer performed by the computerized control system (43) (FIG. 1). The program element (501) is the main program that calls subprograms for loading and manipulating data and converting the loaded data into a form that can be used by the operating elements of the circuit writer. Element (503)
Is a machine action sequence (MAS) file loaded by a main program from a peripheral storage device such as a disk drive and stored in a program element (507), a binary buffer. Element (505) is a pre-computed machine motion list (MML), also loaded from the peripheral storage and stored internally as element (511), the primitive list. Primitive lists primarily perform a number of primitive actions that can be combined in sequence to cause a circuit writer to write traces corresponding to a layout created by the routing engine and stored in a binary buffer. 3 is a list of acceleration vectors in a form recognizable by a driven element (motor). Sine and cosine
Table is also loaded from the peripheral store and stored internally as represented by the program element (537,539).

Element (509) is a subprogram, called SCALE, C in this preferred embodiment, which scales all of the addresses of the current record in the binary buffer during operation and returns this scaled result to the binary buffer. is there. The element (513) is SCALE, C and CREA in this embodiment.
Another subprogram called TE, C, element (515),
Are pre-programmed files of various functions used by. CREATE, C reads the trace data from the binary buffer, finds the correct set of motor primitives from the primitive list, and creates an element (517) called the machine control list in the preferred embodiment, as directed by the main program.

XLATE, C (Translation, C) in the preferred embodiment
An element (519), called a, is commanded by the main program to transform the machine control list into four separate lists. These lists are: element (521), X-LIST; element (52
3), Y-LIST; element (525), Z-LIST; and element (52
7) The actuator list, that is, ACT-LIST is displayed. Each of these lists is a sequence of actions that the corresponding control element, ie X-drive, Y-drive, Z-drive and valve actuator, should take, which action must take place in order to write the required trace. They are listed in the order with their respective time bases.

Element (529) is a subprogram called ISR, ASM called Interrupt Service Routine in the preferred embodiment. This program element is invoked on a repeating time basis, 0.5 ms in the preferred embodiment. When activated, it compares the current time with the times listed in the various action lists. If the time values are correct, it is the time to accelerate, ie update the actuator for its control function. The ISR stores the current position for each axis, and in the preferred embodiment, every 0.5 ms, the position is updated by the formula X = VT and the velocity is calculated by the formula V = AT.
Updated by

The interrupt service routine signals the interface (531) for the x-axis, the interface (533) for the y-axis, and the interface (535) for the z-axis, and the valve or valve actuator to be controlled. Send it. Elements (531, 533, 535) are digital-to-analog conversion modules that convert digital information into analog signals to control the x motor (541), y motor (543) and z motor (545). Through the movement of three motor drives and the actuation of at least one valve to start and stop the supply of PTE material, the trace is
Written on B.

CIRCUIT BOARD REQUIREMENTS In the preferred embodiment, circuit lighters are generally supplied with blanks that meet certain standards. This is important because the locations of the conductive pads to which the component leads are connected, such as by soldering, can be provided as data to the computerized control system. A programming procedure similar to that commonly used in the art can now be used to "route" the conductive traces connecting the pads. The conductive traces form circuit connections between the pads and thus the component leads. What forms the circuit connection are the conductive traces defined by the circuit writer. To provide environmental protection, to prevent short circuits between traces, and to allow conductive traces that cross beyond the previously written conductive traces, to increase the density and complexity of the circuit completed by the circuit writer. Non-conducting traces can also be written on top of the conducting tray to increase the number. In particular, blank specifications relating to pad size and position include the set of "primitives" given to the carriage and pen tip, the minimum set of movements from which all required movements can be composed, and Determined by "router rules", the geometric constraints typically required for traces constructed by extrusion. Primitives and router rules are software choices and can be changed in response to different needs, so that many different standard blanks can be adapted by program changes without departing from the spirit and scope of the invention. Can be done.

FIG. 10 shows standard and desirable pad dimensions for a typical circuit board made with the circuit lighter of the present invention. Typical pad (611) length L1 is 60mil (1.25mm), tolerance about 5
The width L2 is 40 mil (1.02 mm) and the tolerance is about 5%.
The pad typically has a through hole (613) with a diameter L7 of 31 mil (0.79 mm) and a tolerance of about 10% for inserting a lead wire from a component such as a resistor, where the lead wire is Connect to the pad by soldering or other adhesive. The pad material is preferably copper plated with nickel and gold to improve the adhesion between the trace and the pad. No holes are required for components designed to be surface mounted.

Blanks used by circuit lighters typically begin with a laminate with copper plates bonded to one or both sides, similar to conventional PCBs. Unnecessary copper is left behind, leaving isolated pads of the required size and shape where needed, and leaving other areas of the copper surface separate from the pads, often to be used as ground or power planes. Removes corrosion.

The area (615) at each of the four corners of the plate is defined as the "landing zone", and in the preferred embodiment dimension L3 is 12 mils (0.30 mm) and L4 is 14 mils (0.36 mm).
mm). This is nominally the area of the pad that the connecting traces can cover. One such area in one corner is shown in FIG. The smaller area (617) is known as the "critical landing zone", which is the minimum permissible area in which the trace can be mounted. In the preferred configuration, the dimensions of the critical landing zone are L5 = 9mil (0.23mm) and L6
= 8mil (0.20mm). On one side of the board, the PTF trace can end anywhere in the four corners with a total of up to four trace terminals per pad. Plated through-holes can have the same standard pad on the other side of the board, and up to four traces can end there, reducing the total number of possible traces per pad to eight To increase. Those skilled in the art will appreciate that other shapes for the pad could be used, as long as the pad provides the appropriate area for the trace connection.
For example, a circular pad could be used, and a pad with a different number of corners could be used. In each case, however, the number of traces that may be required for a particular component, as well as the "real estate" of the plate available for tracing, and the very beginning and ending of the traces in one corner There is a compromise between the difficulty of hitting the target.

FIG. 11 shows four pads (619, 621, 623, 625) on a typical board (627) made with the circuit lighter of the present invention. Only a small area representing a portion of the plate is shown.
In the preferred programming of the circuit writer, the relationship between the pad centerlines is L8 = L9 = 100 mil (2.54 mm).

FIG. 12A shows three pads (629,631,633) of the desired size and arrangement, with connecting traces on one side of plate (635). Trace (637) is pad (62
9) Touch a corner and trace (639) is pad (631)
Touches one corner of the pad and the trace (641) touches one corner of the pad (633). Trace (643) passes through the area of the three pads, but does not touch any of the three pads shown. The trace (644) contacts one corner of the pad (633) and intersects the underside of the trace (643). By enclosing the conductive traces with insulating material, additional intersecting traces on the first layer of traces can also be added to prevent short circuits and other disturbances.

When writing multiple layers of traces on a board, typically multiple write passes are made. One pass is a procedure to write a series of traces with one PTF material without intersecting patterns. After the first pass makes some connections between the pads, a second pass is made using insulating PTF material to cover all or part of the first pass, and then a third pass And where the traces of the first pass are protected by an overlying layer of insulating PTF material, traces of the conductive PTF can be made to intersect over the conductive traces of the first pass. The number of layers that can be formed is logically constrained by the use of landing zones on the pad, and in practice is constrained by the complex terrain that would require careful control of the position of the extruded tip height. It

12B, 12C and 12D show different views of a portion of a two-layer board made by a circuit lighter using a cross pattern. FIG. 12B shows two rectangular pads (633, 635) on a portion of one surface of the plate. The pad is separated from the power plane area (685) by a groove (634,636) that has been corroded. Trace between pads (63
7) is written. It is shown that three more traces (639,641,643) written by the circuit writer pass through the area between the pads (633,635) but do not touch any of the pads.

Figure 12D is a portion of the opposite side of the PCB, with two additional pads (645,647) and a trace (64) touching the pad (647).
9), and a trace (651) that passes through the area between the pads, but does not touch either pad, and does not intersect either above or below trace (649). Pad (645,6
47) is precisely aligned with the pads (633,635) on the other side of the PCB.

FIG. 12C is a sectional view of the PCB taken along line 12C-12C in FIG. 12B. All elements of Figures 12B and 12D are shown. First
As can be seen in Figure 12B, trace (637) intersects over trace (639), but traces (641,643) together intersect over trace (637). This relationship can be seen more clearly in the sectional view of Figure 12C. Further, the trace is a composite trace formed from the two materials. Traces (637) are formed from conductive material traces (653) and insulating material coating traces (655). Similarly, trace (639) has conductive traces (657) and insulative coating traces (659), and trace (641) has conductive traces (66).
1) with insulating coating traces (663) and traces (64
3) has conductive traces (665) and insulative coating traces (667) It is the insulation of the traces that allows crossover without causing a short circuit between the conductive traces.

On the opposite side of the PCB, the trace (651) has a conductive trace (673) and an insulating coated trace (675), and the trace (649) has a conductive trace (669) and an insulating coated trace (671). This is true even if these traces do not show a crossover. It is reasonable to have crossovers involving these two traces elsewhere on the PCB, and even if there is no crossover, the insulating coating has a protective effect for the conductive traces, Or prevent short circuit between traces due to invasion of different materials.

Figure 12C shows the pads (633) and pads (64) on each side of the PCB.
Between 5), a hole (677) through the PCB is shown, and a hole (679) connects the pad (635) and pad (647). Hole (677) is lined with copper material (681) and hole (679) is lined with copper material ((683). Copper material is typically used during electroless plating during PCB blank fabrication It is applied during the preparation of the blank before trace writing by a circuit writer, and it is the conductive lining of the holes that establish the electrical contact between the pads on each side of the PCB.

Also shown in FIG. 12C are surface power planes (685,687), which, during the fabrication of the blank, typically form a portion of the copper clad that is bonded to the non-conductive plate at the same time the pads are formed. Is a copper plate formed by corroding and removing. There is also a dry film solder mask (689,691) that is typically formed by conventional techniques prior to circuit writing.

12E, 12F and 12G show different views of a portion of a printed circuit board similar to the board shown in FIGS. 12B, 12C and 12D. The main difference between the two plates is known as the two-layer plate, in the plates of Figures 12B, 12C and 12D, where all the elements are on one or the other side of the plate, the 12E
In the plate of Figures, 12F and 12G, there is a conductive element inside the plate. The power plane (695,697) is
Conductive traces of copper formed on the surface of a thinner plate, which will later be laminated so that the power planes will be embedded at two different heights in the resulting plate. The elements on each surface, including the traces written by the circuit writer, and the internal power planes make up the four layers of this four-layer PCB.

One of the conventional methods of preparing circuit boards, especially prototype circuit boards, is by connecting thin electrical wires between the conductive through holes on the boards. Such boards are "wire wound" in the industry
Also called a "wire wrap" board, or pwb, this practice is a typical method of the prior art to make a prototype of the board. Boards prepared by circuit lighters are capable of achieving circuit densities comparable to those of wire wound circuit boards of at least 6 layers and optionally 8 or 10 layers.

As mentioned above, extruded polymer thick film for tracing would be a slight modification of the router convention normally used in wet process fabrication. In the preferred embodiment, industry plates typically do not have landing pads for connecting component leads, so one new general rule is that the extruded PTF must end in one corner of the pad. Also, there can only be one trace in a corner. Similarly, as traces enter and leave the pad, they are generally constrained to extend a distance before bending, to leave room for attachment to other pads. A typical distance is the sum of trace spacing and half the trace width. Another rule is to avoid bends that are too close. This is typically done by making one bend and then requiring the trace to continue a certain minimum distance before making the next bend. A typical example of such a request is
It would require that the distance before making the second bend be 1/2 of the trace width plus the trace spacing. Another rule is that crossovers are allowed. However, for the sake of convenience of the device that is currently in operation, one specific part is 1
Only individual crossovers are allowed. An additional general rule is that the traces should cross at right angles. Both this latter rule and all of the above rules are based on the convenience that each line segment of the trace is in the x, y axis direction. Obviously, many of these conventions can be relaxed or eliminated altogether if the convenience of the x, y orientation of the line segment making up the trace may be compromised. For the sake of convenience, one supplementary rule used today is that there is never one trace on a trace that follows the same direction. However, as described below, when higher densities are very important, this rule can be relaxed. Due to the change in the general rule of routers, the x-
It is possible to take advantage of the y-ness, yet to simulate routing in the form of a wet process plate or wire wrap.

As mentioned above, it may be desirable to have one trace along the top surface of another trace. By relaxing the general rules of the router, this arrangement saves board space, increasing the traces that can run between adjacent pads. Figure 12H shows two pads, each pad contacting a trace in one corner. Trace (715) extends from one pad and bends 90 °, and trace (716) extends from the other pad and trace (7)
Bend in the same direction as 15) and overlie the top of the trace (715). FIG. 12I is a sectional view taken along line 12I-12I of FIG. 12H and shows these two traces. The trace (715) has two parts, a conducting part (717) and an insulating part (719). At the AA cross-section where the two traces overlap, trace (716) rides directly on trace (715). Trace (7
16) also has two parts, a conductive part (721) and an insulating part (723). Typically, each part of each trace is written by a separate pass of the write carriage. The conductive traces of the two traces do not touch and therefore there is no electrical interference between the traces.

Alternative Polymer Delivery and Delivery Devices In addition to the standard valve device described above, there are several preferred alternative embodiments for polymer delivery and delivery that have operational and manufacturing advantages over standard valve devices and Directions are used. FIG. 13A is a side view of the write carriage (800) of a preferred alternative embodiment, hereinafter referred to as the Minibung embodiment, but with some differences from the elements of the embodiment shown in FIG. 6A. Use that element. The viewing direction of FIG. 13A is the same as that of FIG. 2E, showing a cross-section through the crossrail assembly adjacent the write carriage. Bearing blocks (363, 365) are attached to the spacer plate (361) and the assembly runs on the schnaber car rail (357) exactly as in the previous embodiment shown in Figure 6A. The z-direction drive of the minibang embodiment is substantially the same as the other preferred embodiments described above.

FIG. 13B shows the writing carriage of FIG. 13A as indicated by arrow 13B-1.
3B is a view as seen in the direction of 3B, in which two z-direction driving units, that is, one driven by the electric motor (821) and the electric motor (8
53) driven by. Each z-direction drive carries a minibang polymer extrusion unit. The mini bang (801) is carried by an assembly driven by a motor (821) and the mini bang (827) is a motor (8).
53) carried by the assembly driven by.

The mini-bang (801) is fixed to the vertical slide of one z-direction drive by a thumb screw (805), and the mini-bang (827) is fixed to the vertical slide of the other z-direction drive by a thumb screw (831). . Each minibang stores a certain amount of polymer and quantifies it via a write chip to write a circuit trace. Typically, one minibang quantifies the insulation and the other quantifies the conductive polymer.

Each of the two circuit writing assemblies on the writing carriage has a polymer tank that is extruded by gas pressure to supply polymer to each mini-bang. Polymer tanks (807)
Replenishes the mini-bang (801) via the supply line (803), and gas is sent to the tank (807) via the gas line (809). A remote control valve (811) controlled by an electric signal from the control system (43) via the control line (825) opens and closes the gas supply to the tank (807). The polymer tank (839) is connected to the mini bang (82) via the supply line (829).
7) is replenished and the gas pressure is supplied to the tank (839) through the gas line (841). A remote control valve (843) controlled by an electric signal from the control system (43) via the control line (851) opens and closes the gas supply to the tank (839).

Each polymer tank is a modular unit that can be quickly removed and replaced with another polymer tank. The tubing is attached to the tanks by quick disconnect fittings, each tank being a shelf (817) in the preferred embodiment.
It is held in place by a clamp (not shown). The ability to replace tanks quickly allows new polymer sources to be inserted at the start of operation, and new sources can be added quickly as needed or when the previous source is empty. be able to. Polymeric materials are typically stored in refrigerated hangars to delay premature polymerization, and heaters are added to the minibang near the writing tip to bring the polymer to the required working temperature. You can

Each minibang unit has a storage capacity that stores less polymer feed than the capacity of the replaceable tank. The storage capacity of the mini-bang is calculated to have at least the amount required to write a typical trace in a single pass. Mini-bangs are built into each mini-bang and each tank is timed during the writing pass by a unique valve and metering device driven by gas pressure supplied via a gas line attached to each tank. Refilled from.

When the polymer is delivered to the minibang storage volume, the gas delivery valve is closed to the tank and writing begins. The polymer is energized from the mini-bang by gas pressure supplied from the same source as the gas to each polymer tank. Gas to the mini bang (827) is supplied via line (837) and is opened and closed and pressure controlled by a gas control unit (847) operated via control line (849). Gas to the mini-bang (801) is supplied via line (819) and is opened and closed by a gas control unit (815) which is operated via control line (823).
The pressure is controlled. Each mini-bang has a gas actuated piston to bias the polymer from the writing tip, and the polymer flow rate determined from the mini-bang is measured by the LVDT device (13A).
The position and movement of the piston is sensed by means of a view (not shown in Fig. 13B) or remotely monitored. Mini bang (80
The sensing device for 1) is controlled via the control line (833) and the device for the minibang (827) is controlled by the control line (8).
35) controlled via.

FIG. 14A is a sectional view of the mini-bang (801). 14A
The figure shows a typical mini-bang (827). There are three main parts, a body part (855), a metering part (857) and a writing tip part (859). A central passage (861) passing vertically through the main body portion connects the fixed quantity portion (857) and the writing tip portion (859). A second passageway (865) through the body (855) connects to the passageway (861) at a substantially right angle. The passageway (865) has a threaded portion (867) and a smaller diameter portion (869) than the remaining passageways.

A movable shut-off piston (863) in the passage (865) controls polymer inflow from the feed line (803). Line (80
Polymer entering from 3) passes through the passage (897) and the passage (865)
to go into. The passageway (897) is shown at a 90 ° offset with respect to the body (855), but this is for convenience only. The piston (863) is sealed in the passage (865) by an O-ring (871) inside the piston, and the piston is coil spring (8
It is biased in the direction of the vertical passage (861) by 73). Adjustable stop (87) on threaded portion (867) of passageway (865)
3) limits the process of the shutoff piston (863), and the spring (87
3) Adjust the pressure applied to the piston (863).

The insert (877) in the passage (865) is the guide passage (87
9) and the shutoff piston (865) has an extension (881) that fits in the guide passage. A passageway (883) is created in the extension (881) to provide a conduit for polymer between the passageway (865) and the passageway (861) in the body (855).
When the piston (863) is in the retracted position shown in Fig. 14A,
This passage (65) is open to allow material to pass. Figure 14B shows Figure 14A.
Shows the same cross section as the figure, but in this case the piston 863)
Is in the advanced position, closing the polymer passage. Extension (885) is a replaceable tube for adjusting the diameter and length of the polymer passage.

The mini-bang metering portion (857) has a central cylindrical volume (887) of diameter substantially equal to the diameter of the passageway (861) and has a snug metering piston (889). The metering piston is made of a magnetically permeable material, and in the preferred embodiment is a magnetic stainless steel. Metering piston (88
9) is slidable vertically in the inner diameter of the volume (887). An LVDT device (891) surrounds the passage (887) and magnetic piston (889), and an electrical lead (8) to the control system (43).
The position and speed of the piston (889) is monitored via 33).

The writing tip portion (859) is attached to the body (855) at the end of the passageway (861) opposite the metering portion and has an internal passageway (893) through which the polymer passes during the circuit writing process. . The aisle (893) ends in a writing chip (895), which writes traces on the PCB during the circuit writing process.

The operation of the refilling / extruding device of the mini bang embodiment is as follows.
13B, 14A and 14B are described in detail. When the circuit writing work is completed and the polymer supply in the volume (887) is almost consumed, the volume is refilled from the tank (807). The gas control unit (815) is actuated by the control system to depressurize the gas line (819) and the valve (811) is opened to apply gas pressure to the tank (807) from a pressure regulated external source. . The feed pressure is typically about 50 psi (3.52 kg / cm ² ). The gas pressure above the polymer supply is due to the face of the piston (863) (899) (14th
(Fig. B), the difference between the atmospheric pressure and the gas pressure on the opposite side of the piston over the area of the surface (899) is within the passage (865) from the closed position shown in Fig. 14B to the open position shown in Fig. 14A. Gives enough force to move the piston (863).

When the passage (883) is exposed to the passage (865), the tank (80
The polymer from 7) passes through the extension tube (885) and into the passageway (86
Flow to 1). Since the gas pressure in tube (819) has been released, the piston is biased upwards and volume (887) is filled with polymer. The position of the piston (889) is monitored by the LVDT device and the cavity (887), passageway (861) and passageway (893) are filled with polymer to complete the fill at the preset location. There is no flow from the writing tip during filling because the polymeric material has rheological properties such that the filling pressure does not create sufficient internal chip pressure to initiate flow from the writing tip. Closing valve (811) vents line (809), removes gas pressure from the tank and also removes gas pressure from face (899) of piston (863), and spring (873) causes piston (863) to move. ) To the closed position shown in Figure 14B.

To write a trace with the write tip (895),
According to the above description regarding another preferred embodiment, x, y
It is necessary to activate the z and z drives to control the polymer flow. Polymer flow in gas control unit (815)
Controlled by a control system through the unit, the unit controls both the flow rate and pressure of gas to line (819). In the preferred embodiment, the control unit (815) is a Norgren Reedex model number NC-V3.
21P3-2BNN Built-in pressure control valve and pressure sensing transducer. The gas pressure above the piston (889) biases the piston downwards against the polymer in the volume (887), causing the polymer to be extruded from the writing tip. The position and speed of the piston (889) is monitored by the control system along with the gas pressure in the line (819) and a preprogrammed polymer flow actuates the control unit (815) depending on the sensed parameters. It is achieved by When the position of the piston (889) again indicates that the mini-bang's containment volume needs to be refilled, the refill operation is performed again.

The second circuit write assembly on the write carriage using the minibang (827) operates in substantially the same manner as described above for the first minibang assembly. Typically, one assembly is for extruding the conductive polymer and the other assembly is for extruding the insulation.

Circuit Board Milling, Cutting and Alternative Configurations The ability of circuit writers to move a circuit writing assembly in three dimensions and follow programmed and calculated paths to create precise and complex patterns is described in detail above. Gives even greater capabilities to the prototype development, fabrication and repair of printed circuit boards that did not exist. FIG. 15 is a side view of a carriage similar to the carriage shown in FIG. 13A, but the carriage of FIG. 15 supports and operates a cutting head instead of an extrusion assembly.

In FIG. 15, the cutting head (901) is held by the tightening screw (805) on the z drive slide in the saddle (911). If the cutting head is installed, no polymer tanks or gas control elements to operate the tanks or minibangs are required, so such elements are not shown in FIG. The variable speed electric motor (903), the tool chuck (905), and the cutting tool (907) are important elements in the cutting head (901) that is to be used for an application that requires cutting. Electric motor lead wire (909)
Is controlled by the control system (43).

In the cutting head installed in place of the extrusion assembly in the circuit lighter of the present invention, the tool chuck (905) is a small diameter milling cutter and drill tightening device and the tool change is to remove the PCB blank for processing. It is done manually by the operator with the cutting head moved away from the area where it will be installed. In an alternative embodiment, the various tools are stored in shelves in the change area at locations stored by the control system, and the chuck is electrically operated by the control system. In an alternative embodiment, the change of usable cutting tools is programmed and performed automatically.

The cutting tool in the above cutting head is one of a variety of cutters and drills designed to perform a particular type of work on a PCB. For example, attach a drill with a diameter of approximately 0.028in (.71mm) to the tool chuck, and have a diameter of approximately 0.028in (.71m).
Precise and intricate patterns of holes m) can be made in printed circuit board blanks. Such a pattern of holes is useful for prototype development work, for example, for attaching leads from separate components. Instead, a milling tool is attached, and certain areas of the copper coating on the PCB blank are milled away under program control and the isolated areas of the conductive copper coating are used as conductive pads for the written circuit. You can leave. The cured polymeric material on the blank can also be cut to form useful features. The useful work that can be done on the prototype development, manufacturing and repair of a PCB with a circuit lighter device with a cutting tool attached to a carriage is very diverse.

A common requirement in the fabrication of many prototype PCBs is to make conductive pads and connect the pads with conductive traces. Pads are attachment points for leads from separate components that are added to the board to complete the circuit. The conductive traces between the pads then provide a conductive circuit between the different components. Many alternatives can be utilized in the creation of PCB structures such as pads and traces, using a combination of cutting and circuit writing techniques with coated or uncoated PCB blanks and circuit writer equipment. Some applications are described in the following sections and are numbered for future reference. In the example, the traces and other dimensions are comparable to those described for the similar structure. Such dimensions vary with design rules.

1. Figure 16A is a partial cross-sectional view of the elevation of a coated blank used as a starting point for prototype development work. The blank is a non-conductive, reinforced epoxy material (913) with copper layers (915) coated on both sides, and an insulating layer (917) of polymeric material overlaid on the copper layer. Although not a requirement, gold can be flashed prior to depositing the polymeric material on such a cladding to improve resistance contact. In the first stage,
Using the equipment with the cutting head installed, mill through two outer material layers to a non-conductive blank to create a pad. FIG. 16B shows a groove (91) that was cut through two outer layers on one side to create a substantially rectangular pad (921).
It is a reduced scale plan view of 9). The substantial rectangle is arbitrary.
Any desired shape of pad can be milled. Also, if the component mounting technique used requires holes, holes can be drilled during the cutting operation through the plate's connection pads on either side of the plate. Holes are not shown in FIGS. 16A-16D.

Figure 16C is a partial cross-sectional view through the pad (921) and groove (919) on one side of the blank. In FIG. 16C, an insulating overlayer will still be present on the pad just created, which will prevent attachment of the individual components.

FIG. 16D is a cross-sectional view after additional steps to FIG. 16C. Using the equipment with the cutting head installed, the insulative overlayer on the pad is cut away, leaving the exposed copper layer for attachment of the individual component leads. Groove (919)
Is a circuit lighter fitted with an extrusion assembly used with an insulative polymer, filled with an insulative polymer (923), and a conductive trace from a newly formed pad to another point on the PCB. (925) is written. The conductive traces (925) are insulated from both the bottom layer of copper in the non-pad area of the PCB by both the groove insulation (923) and the insulating overlay (917), and the top surface by the insulation extrusion (926). It is insulated. This procedure can be used to create multiple mounting pads on a board and to connect to pads in a circuit pattern by conductive traces. Those skilled in the art will recognize that the remainder of the coating surface not used for the pads can be used as a ground plane or power plane.

2. Figures 17A, 17B, 17C and 17D illustrate applications beginning with bare cladding. The starting plate shown in partial cross section in Figure 17A is a non-conductive reinforcement (927) with a copper coating (929). In the first stage, as in the case of the procedure # 1, the groove was cut by milling through the coating layer,
Form isolated copper pads. Although not shown, holes may be drilled to connect the pads on both sides if desired. Insulation material (93
1) is written to form an insulating subgrade, and then conductive material is written on this insulating material to give conductive traces. Insulating subgrades insulate the conductive traces from the copper clad areas between the pads. If further protection of the conductive traces (933) is desired, an insulating overlapping trace (935) of the conductive traces can be written, then the traces are crossed and a circuit of two or more layers is written. be able to.

Figure 17C is a cross-sectional view of conductive traces on an insulating subgrade. Figure 17D shows the first with the addition of insulating lap traces.
FIG. 7C is a sectional view of FIG. 7C. The addition of overlapping traces will completely wrap the conductive traces between the pads. The relative shapes of the insulating subgrade, the conductive traces and the insulating lap traces control the rheological properties of both conducting and non-conducting polymeric materials, including the writing tip, Z-height and each. Controlled by selecting the pressure used to extrude the material.

3. Another alternative example of traces between pads formed by cutting grooves in a copper clad plate as in Procedure # 2 above is illustrated in FIGS. 18A, 18B and 18C. . FIG. 18A is a plan view showing two substantially rectangular pads (937,939) formed by milling grooves (941,943) through the copper cladding (949) of a cladding blank. Another groove (945) connecting the grooves (941, 943) is milled through the copper coating.
The cut grooves (945) serve the purpose of the insulating subgrade of Procedure # 2 above. Within the boundaries of the groove (945), a conductive trace (947) is written between the pads (937,939) with a width that is much smaller than the width of the groove (945), so that this conductive trace is copper covered on both sides of the groove. Do not touch. Figure 18B shows 18B in Figure 18A.
18B is a cross-sectional view showing a conductive trace in the groove between the buds. FIG. An additional insulating overlay (948) may be applied to the conductive traces as shown in Figure 18C.

4. Figures 19A, 19B, and 19C show procedures for using a circuit lighter device, in various embodiments, to produce polymer pads on non-conductive, uncoated plates. 19th
Figure A is a plan view showing five traces written side by side. Trace (951,955,959) is an insulating polymer and trace (953,957) is a conductive polymer. No. 19B
The figure is the 19B-19B section of FIG. 19A, where the three insulating traces in the side-by-side array are higher than the conductive traces from the plate surface. Trace (961,963) is an insulative trace and is written at an angle of approximately 90 ° on five side-by-side traces. After the traces and pads have been formed, the board is cured and the components are mounted using mounting equipment such as conductive adhesives or solders standard in the art. First
Figure 19C is a section view taken along 19C-19C in Figure 19A, showing the relationship of one conductive trace to two crosswise insulating traces. The placement of the insulating traces relative to the conductive traces forms two pockets where the component leads (965,967) align with and ride on the conductive pads. The use of two conductive trace pads is optional. As many trace pads as desired can be written side by side or in other relationships. After forming the polymer pad, the traces from one pad to another can be written as above using a conductive polymer.

5. Many PCBs with internal conductive planes, often used as ground planes, are fabricated. In the course of the prototype development of this type of PCB, a special issue is the ability to connect from one pad of the cladding to the other while avoiding a short to the internal conductive plane. The path from one side of such a plate to and through the internal plane is sometimes called a via.

FIG. 20 shows a plate (96) with a copper coating (971) on one side, a copper coating (973) on the other side, and an internal conductive plane (975).
It is a sectional view of 9). The groove is cut as described in the above procedure to create two pads (979,981). In the next step holes (983) are drilled through the pads (979, 981) and the internal plane (975). After drilling, the holes are filled with insulation by polymer extrusion using a circuit lighter. In the hole filling process, the writing tip of the circuit lighter is brought close to the board at the position of the hole until the material is almost pushed into the hole, or the material is inserted into the hole, or the chip is inserted into the hole and the extrusion is started, This can be done either by pulling up the chip or by raising it.

The insulation is cured, although the board typically needs to be removed from the circuit lighter. After curing
The plate is reattached and a hole (989) smaller than the diameter of the hole (983) is drilled approximately on the centerline of the hole (983). As an example, it is drilled approximately on the center line of the hole (983). As an example, the diameter of the holes (983) is typically 0.020 in (0.5 m
m) and the diameter of the hole (989) is 0.010 in (0.25 mm). Using the circuit lighter again, this time the conductive polymer is extruded into the holes (989) and overlaid on top of the insulating polymer at both ends to contact the two pads (979,981). As a result, the insulating torus (985) effectively insulates the conductive polymer core (987) from the internal plane (987) while simultaneously connecting the internal conductive core to the two pads on each side of the plate. Will be done.

6. Figures 21A and 21B illustrate a second procedure for connecting pads on opposite sides of a plate having an internal conductive plane. The plate (991) has an outer coating (993,995) and an inner conductive plane (99).
Have 7). The pad (999,1001) is produced by milling the groove as described above.

A hole (1009) of width D is cut through the plate between the two pads. The holes are slanted and have a length L on one side and a length S on the other side. The longer dimension is on the cutting side. If the design of the board and the design rules are different, the dimensions can vary considerably. A typical length L is 3 mm and a typical length S is 1 mm.

A first bed (1003) of insulating polymer is extruded using a circuit lighter. The floor (1003) spans the entire width D of the hole. Dimension D is typically about 1 mm. A conductive polymer trace (1005) is then extruded onto the bed (1003) to a width narrower than that of the bed (1003). The trace (1005) contacts both pads (999,1001). The holes are then filled with an insulative polymer (1007) to completely enclose the conductive traces, eliminating the possibility of contacting the interior plane (997).
As a final step in the procedure, the board is removed and the polymer extrudate is cured. The advantage of this procedure is that it does not require an intermediate curing operation like the via procedure for drilling holes between pads.

7. The capabilities provided by the various operating modes of the circuit writer provide other possibilities, creating the composition of the PCB. Extruded, cured polymeric materials, both conductive and insulating, can be cut, for example. 22A
Figures and 22B illustrate a procedure for producing an extruded polymer pad having seams for individual component leads, somewhat different from the polymer pads described above.

FIG. 22A is a plan view of the procedure for aligning a polymer pad with matching features for individual device leads.
FIG. 22B is an elevational view as seen in the direction of the arrows on lines 22B-22B in FIG. 22A. Two insulating traces (1011, 1013) are extruded side by side and cured. After curing, use a circuit lighter to cut the three grooves (1015, 1017, 1019).
Next, cross the path of the original two insulating traces into the cutting groove and place the conductive polymer traces (1021,1023,1025).
Is extruded. The conductive traces are extruded so that the height from the plate surface is lower than the insulating traces. After the conductive traces have been cured, they serve as mounting pads for the leads of individual devices, and the difference in height between the conductive and insulating traces is a matching feature for the leads of the device to which they are attached. give. The two insulating traces and the three conductive traces are arbitrary. Of course, as an alternative, it is of course possible to first provide the conductive traces. This is illustrated in Figures 23A-23C. The conductive traces (1031,1033,1035) are first extruded onto the substrate. Next, as shown in FIGS. 23B and 23C,
Extrude one layer of insulating trace (1037) over the conductive trace. This is typically done in two or more passes of the insulating trace. The plate is then cured and milled to provide a conductive trace (1031,1033,10) with a precisely flat top surface.
Clean the sidewalls of the insulating layer (1037), as shown in Figure 23D, leaving 35).

Polymeric Material Considerations The first and second materials, that is, the materials used to form the conductive and insulating traces, are of some desirable nature for successful operation with the apparatus of the present invention. Formulated to have properties. In particular, the rheological properties of the first and second materials are tailored to particular device embodiments, such as tanks, piping, devices for producing polymer solutions, and the like. These impose constraints on the rheological properties of the first and second materials. Desirably, the first and second materials have the following rheological properties: (i) little or no swinging hysteresis with increasing or decreasing stress, such as that which may occur during the sticking or extrusion procedure. Not shown at all.

(Ii) It is pseudoplastic.

(Iii) Curing between layers of different traces, as it causes a slight increase in viscosity immediately after extrusion, causing only a slight physical deformation whenever a crossover trace is placed on an existing trace during the circuit writing process. Does not need

In terms of mechanical properties, the material must successfully flow out of the scraped tip, but it should not flow once applied to the surface of the PCB, rather it has a relatively narrow trace width and excellent conductive or insulating properties. It must have sufficient mechanical stability to maintain a suitable thickness to provide any of the capabilities. As a practical matter, in the preferred embodiment, these mechanical properties correspond to having a practical (conductive) material viscous range of 15,000-30,000 cp at a static shear rate of 20 / sec, of about 0.01. At low shear rates below <RTIgt; / sec, </ RTI> the working viscosity range should be between 1 and 5 million cp, which is extremely stiff. But in principle
A slightly narrower range of 20,000 to 27,000 is more desirable at higher shear rates, and the most desirable range is 22,000.
~ 25,000 cp. For the second (insulating) material, the practical range of viscosity at high shear rates of 20 / sec is about 15,000-30,000 cp.
, And a more desirable range is about 20,000 to 22,000
cp. At low shear rates of less than about 0.01 / sec, the practical range also appears to be about 1-5 million cps, with the preferred operating point being 2.5 million cps, as is the conductive material. But,
Viscosity is temperature dependent in some formulations, and when using the desired materials and equipment it is sometimes useful to control the temperature of the writing tip to obtain the required flow characteristics. For example, in Example 2 described later, a writing chip temperature of 40 ± 1 ° C. is desired. In that formulation, viscosity is a well-defined function of temperature. Therefore, it is useful to control the temperature well during circuit writing in order to properly control the shape and repeatability of the trace. Higher temperatures could be used, such as 60 ° C, which would alleviate some of the temperature constraints. However, as the temperature increases, the operating temperature approaches the polymerization temperature. In Example 1 described below, temperature control is not typically used.

Controlling the rheological properties of the first and second materials used to form traces on a circuit board by the circuit lighter of the present invention can be accomplished in several ways, including the first or As a component of the second material, a resin having an appropriate molecular weight, that is, a polymer, a kind and an amount of a solvent, a reactive functionality contributing to polymerization, a catalyst, and the like are included. Guidance for making such selections can be found in many standard reference books in Polymer Science. For example, Mark et al., “Physic Properties of Polymers”
al Properties of Polymers) "(Washington DC, USA)
American Chemical Society, 198
4); Miller's "Solid State Technology (Sol
id State Technology "(October 1974); Kaufman," Introduction to Polymer Science and Technology (Introduction)
to Polymer Science and Technology (New York City, USA, John Wiley & Sons, 1977); Tess et al. “Applied Polymer Science” (American Chemical Society Washington D.
C, 1985):

Curing, or viscosity increase, after extrusion is accomplished by several methods that depend on the polymer system chosen. For example, partial curing by light energy or heating, drying, and the like. In the desired group of first and second materials, the curing is effected by drying, i.e. solvent evaporation, prior to curing. Such pre-cure drying is performed successfully by mixing a polymer precursor material, a catalyst, conductive particles, and the like with a solvent mixture in which at least one component is a solvent having a high vaporization rate. Solvents having a moderately high vaporization rate include acetone, tetrahydrofuran, ethyl acetate, methyl ethyl ketone and the like. Although not a requirement, it is desirable to have an accelerated drying by passing a stream of heated air over the just applied traces.

Also desirable for the first and second materials are: (1) It is most desirable that the temperature is less than 150 ° C., that low temperature curing is possible; (2) Low ion contamination amount; (3) First In case of material, it has high conductivity after curing: Low temperature cure is desirable so that the substrate to which the traces are deposited does not decompose during the cure process. The substrate typically comprises standard circuit board material. For example, epoxy / glass fiber, epoxy / glass fiber / paper, phenolic plastic / paper, polyimide / glass fiber, Teflon / glass fiber, and the like.

Ionic contamination is not preferred because it can lead to unpredictable polymerization in some desirable polymerization systems described below. Such contamination-induced polymerization significantly reduces the shelf life of the first and second materials, makes their rheological properties unpredictable, and contributes to premature failure of electrical circuits in high humidity environments. Sometimes.

The cure transforms the first material into a thick film of conductive polymer. It is desirable to obtain conductivity by including conductive particles as one component in the first material. Upon curing, the polymer brings the conductive particles into contact with each other, thereby rendering the overall composite, a thick film of polymer, electrically conductive. However, in some cases, contamination alone is sufficient, and shows some moderate conductivity even before curing. The formulation of such conductive polymers is well known in the polymer thick film art. In general, the excellent conductivity of polymeric thick films requires a compromise with excellent mechanical strength. The increase in conductivity is achieved by the relatively high weight ratio of conductive particles in the polymer thick film. Similarly,
Higher mechanical strength is provided by increasing the proportion of polymer in the polymer thick film. That is,
Higher conductivity is typically achieved by some reduction in mechanical strength. The important feature of the first material is
The conductive traces have a higher conductivity than that obtained with commonly used polymeric thick films without loss of mechanical strength. Higher conductivity is obtained by including a high proportion of conductive particles in the first material, but the attendant loss of mechanical strength of the overall structure, ie the conductive traces, is (1) It is avoided by using an insulating polymer that has strength and adhesion to the substrate, and (2) includes conductive traces to form an outer shell around it. That is, according to the first material, it is possible to achieve a higher conductivity, since the conductive polymer requires minimal mechanical strength when wrapped in an insulating polymer. Such encapsulation is possible because the conductive material is applied to narrower traces than the screened layer. Desirably, the first material contains sufficient conductive material so that the 12 mil (0.305 mm) wide trace has a resistivity of at most 0.6 Ω / in (0.24 Ω / cm). Suitable conductive particles for use in the first material include, but are not limited to, silver, silver coated nickel, gold, silver coated gold,
Includes copper and nickel with gold coating. Such particles are commercially available in several forms, such as flakes, powders and the like.

The second material is applied onto the conductive traces in several ways, such as spraying, extrusion and the like. Desirably, the second material is extruded onto the freshly applied conductive traces by the second extrusion device under the programmed control of the trace routing engine. More preferably, the second material is extruded onto the conductive traces after a drying step.

Desirably, the polymeric thick film formed by the second material has a low dielectric constant. The choice of the dielectric constant largely depends on the choice of the polymer system used. For example, ku et al. “Electrical properties of polymers: Scientific principles (El
electrical Properties of Polymers: Chemical Principle
s) ”(Munich City Hamser, 1986). Generally, polymers with fewer axial bonds in the ring have a lower dielectric constant.

Whenever the first and second materials are contacted, a component of the first material reacts with a component of the second material to form a layer of anaerobic polymer at the point or surface where the two materials contact. Believed to form. This anaerobic polymer layer is referred to herein as an interface layer. The formation of the interface layer should proceed rapidly at room temperature. It is believed that such rapid interfacial layer formation occurs in the following desirable polymer systems.

General guidance on the selection of particular compositions, catalysts, solvents, resins, hardeners, etc. for use in the polymer system according to the present invention can be found in the literature.

Most desirably, the first material comprises an epoxy / diamine polymer system and the second material comprises an allyl dicyanate polymer system or an allyl dicyanate / epoxy polymer system. Exemplary compositions of such first and second materials are shown in the following table.

First material Ingredient Weight / weight% Epoxy resin (from short-chain to high-molecular prepolymer) 4
-10 Diamine / polyamine curing agent 0.25-3.5 Low-vaporizing aprotic solvent 1-4 Highly-vaporizing aprotic solvent 2-10 Conductive fine particles 75-90 Selection of epoxy resin to be used is mainly based on required glass fiber temperature of conductor after curing . The most readily available epoxy can be used. Preferred epoxy resins are prepolymers or monomers based on the condensation of bisphenol A (4,4-isopropylidenediphenol) and epichlorohydrin (B stage). Other suitable epoxy resins include epoxy novolaks, polyfunctional amine based epoxy resins and polyfunctional epoxy resins. The manufacturers of such resins are Shell Chemical,
Includes Dow Chemical and Ciba-Geigy.

Desirably, the amines of the deamine / polyamine hardener have reduced latent cure properties. Anhydrides, polyamides and reactive imide containing compounds can also be used as curing agents. When using the anhydride, a suitable catalyst, such as boron trifluoride ethyl amine complex, must also be used to activate the anhydride at elevated temperatures. Most preferably, aromatic amines are used because they provide high temperature resistance and allow latent curing. These compounds include diamine and triamine substituted toluene and other mono- and polymeric aromatics.

Preferred highly vaporizing aprotic solvents include 2-butanone, 4-methyl-2-pentanone, tetrahydrofuran, dioxane, ethylacetate and ethoxytetrahydrofuran. More preferably, 2-butanone is used as the highly vaporizable solvent in the desired first material. The highly vaporizable solvent in the first material is called a first highly vaporized solvent. The first highly vaporizable solvent may also be the same as or different from the second highly vaporizable solvent used in the second material described below. Desirable low vaporization arotic solvents include 2-butoxyethyl acetate and 2-butoxyethyl acetate.
Mesoxyethyl Teeter (Diglyme), Ethoxyethyl Acetate, Propylene Glycol Methyl
Includes ether acetate, and 1-methyl-2-pyrrolidinone. More preferably, propylene glycol methyl ether acetate or 1-methyl-
2-pyrrolidinone is used as the low vaporizing solvent in the first desired material.

Second material (allyl dicyanate) component wt / wt% (excluding special mention) allyl dicyanate) 50-70 Condensing agent 1-8 Aprotic solvent (high vaporization) 1-10 Aprotic solvent (low vaporization) 20-30 Hydroxyl Accelerator 1-6 Metal Catalyst 25-500 ppm Desirably, the allyl dicyanate is bisphenol A, bisphenol F, or a dicyanate ester of bisthiophenol. These materials are commercially available, eg AroCy-B, AroCy-M, AroCy-T, manufactured by Hi-Tek Ploymer (Jffersonto, Kentucky, USA).
wn). Whenever a curing temperature below about 150 ° C is required, AroCy-B is most desirable, about 150-250
Whenever a curing temperature in the range of ° C is required, Ar
oCy M is preferred.

A thickener is used so that the second material is pseudoplastic. For example, evaporated silica, alumina, titanium dioxide,
Many basic or modified inorganic particles such as glass particles can be used.

Hydroxyl accelerators are nonylphenol, 4-hexylphenol, 4-ethylphenol, 4-second-
Butylphenol, 4-tert-butylphenol, 2,
It can be an alkylphenol or a high boiling alcohol, such as 6-di-tert-butyl-4-methylphenol, 2-methylidazole, 2,4,6-trimethylphenol. The most preferred hydroxyl accelerator is nonylphenol.

Various metal compounds can be used in combination with the soluble coordinating metal carboxylates or xylates. Preferred metals include zinc, copper, nickel, iron, platinum, cobalt, manganese, and the like. More preferably, zinc is used in combination with the acetylacetonate chelating agent. The metal catalyst must be dissolved in the hydroxy promoter before combining with the allyl dicyanate to avoid uncontrolled reactions at high catalyst concentration sites. The concentration of metal catalyst is given in ppm relative to the concentration of allyl dicyanate alone. Desirably, the high and low volatility solvents are the same as those set forth in the first material table above. However, the most desirable highly vaporizable solvent is ethoxytetrahydrofuran, and the most desirable less volatile solvent is diglyme. The highly vaporizable solvent used for the second material is the second
It is referred to as a highly vaporizable solvent.

Second material Component% by weight (excluding special mention) Epoxy 5-40 Allyl dicyanate 40-70 Arotic solvent (high vaporization) 1-10 Arotic solvent (low vaporization) 15-30 Hydroxyl accelerator 1-6 Metal catalyst 25-500 ppm Desirably, the allyl dicyanate, epoxy, thickener, solvent, hydroxyl promoter and metal catalyst are the same as those described above for the second allyl dicyanate material.

Example 1 10.4% (by weight / weight) of a high molecular epoxy mixture (Dow Chemical 684EK4, a solution of methyl ethyl ketone containing 40% by weight of epoxyside having an average molecular weight of 10,000).
0), 2.97% 3,5-diethyl-2,4-diaminotoluene (Ethacure 100 from Ethyl Corp.), 5.6% 1-methyl-2-pyrrolidinone, 1.22% cyclohexanone,
1.31% tetrahydrofuran and 78.4% fine silver particles (Silfla available from Handy & Harman)
4: 1 ratio of silver flakes like ke282 to silver powder like Silpowder (Silflake 282 with Handy & Harman)
15.83 Silpowder) (All percentages are weight / weight%
Was prepared). 65.15% (by weight / weight%) AroCy-B-30 (High Tech Polymer), 6.02% fine silica particles (Degusa Corp Degu
A second material was prepared consisting of Aerosil 972) from ssa Corp.), 26.88% diglyme, and 1.95% nonylphenol with 300 ppm (relative to AroCy-B-30) zinc acetylacetonate. Using the device of the present invention,
Test traces were written on a blank FR-4 circuit board substrate. After the circuit was completed, the plate was placed in a furnace at 125 ° C for 1 hour to remove the volatile solvent and then the temperature was 2-4.
The temperature was raised to 150 ° C to complete the cure. 4mil (0.1
0mm), 12mil (0.30mm) wide, 1in (2.54c)
The trace after curing showed a resistivity of 0.5Ω per m)). The insulating coating had a breakdown voltage of over 1000V.

Similar experiments using substrates of Kapton polyimide plates were able to achieve 0.1 Ω / in (0.004 Ω / cm) using higher cure temperatures and longer cure times.

Example 2 A first material was prepared with the following formulation. Silver flake (Handy and Harman 96 Silflake 282
Parts), silver clusters (24 parts for Handy and Harman Silpowder 228) and silver balls (5 parts)
To this mixture was added acetone (15 parts), N-methylpyrrolidone (10 parts) and dimethyl ether of diethylene glycol (diglyme, 3 parts). The resulting paste was passed through a 150 Messi screen.
Epoxy resin (Aribadite GZ 488 N-40, 6 parts) and curing agent (m-phenylene diamine, 1.8 parts) are mixed with a part of the paste (including 65 parts of silver) and stirred to homogenize. A mixture of Acetone was added to this mixture (10 ml) and stirred to obtain a homogeneous mixture. Next, this mixture was exposed to reduced pressure (vacuum degree of 29 inHg (737 mmHg)) for 30 minutes to obtain a pseudoplastic paste. It was extruded under pressure (5-100 psi, 0.35-7.03 kg / cm ² ) through small holes of 5-9 mil (0.13-0 / 23 mm) diameter and attached to the plate. A hot air stream was applied to the extruded material for 5 minutes to dry it to a stiff line and a layer of insulating PTF was overlaid thereon without compromising the performance of any of the layers. This conductive layer could be cured in a furnace with subsequent insulating layers to form low resistivity insulated conductive traces.
While it was possible to cure each layer separately, this one-step cure process saves a considerable amount of time and avoids realignment problems if a cure attempt is made between the conductive layer and its matching insulating layer. This will be understood by those skilled in the art.

The second material (insulating PTF) was prepared with the following formulation. Dioxane (5 parts) and bisphenol A dicyanate (Interez RDX 80352, 16 parts) were added to an epoxy resin (Araldite GZ 488 N-40, 20 parts). In the obtained solution, erotic silica (Cabot.
Silanox 101 from Cabot Corp, 1.6 parts) was dispersed. Acetone (15 ml) was mixed with this dispersion and exposed to reduced pressure (vacuum degree of 29 inHg, 737 mmHg).
An insulating paste with properties similar to the rheological and drying properties of was obtained.

It will be apparent to those skilled in the art that many modifications can be made to the circuit writer without departing from the spirit and scope of the invention. Alternative materials to the specified materials can be used, the dimensions can be changed, the position of the elements can be changed, and so on. As an example, although the preferred embodiment uses a stepper motor, there are other types of motors, such as synchronous motors, that could be used with the appropriate sensors. A stepper motor is chosen because it allows the computer to sense position without the use of external sensors. Similarly, the pad material can be different from that of the desired embodiment, and in the case of a surface mounted component, it will not be necessary at all. Also the pad itself could be composed of PTFs. It will also be apparent to those skilled in the art that a completely different drive could be used, for example a lead screw device could be used to provide the x, y motion. As another example, given a particular size as an element of the circuit writer, the PCB blank is limited to some maximum size for mounting on a writing table, but with larger or smaller boards. Making a circuit lighter to handle does not depart from the spirit or scope of the invention. It would also be possible to install more than two writing assemblies on the writing carriage so that each applies a different material, or all apply the same material. The device was also described as making plates without vias, but in some cases vias may be needed, so this extrusion PTF is routed with or without vias. I reserve the choice. Also, in some cases, it may be desirable to mix various methods. For example, while the conductive traces are provided by extrusion, it may be useful to provide the insulating layer on the entire plate, not just on the conductive traces. Furthermore, although the circuit writer has been described in relation to a flat circuit board, there is no inherent limitation on such two-dimensional substrates that limits the method of the present invention, and in fact, three-dimensional structures as well as those of the present invention. It could be configured by the method. Different computer platforms and data storage devices could be used, and many variations in programming and data processing elements could be made, all of which are set forth in the appended claims. Without departing from the spirit and scope of the invention.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Arley, Robert B. Two Hundredthence North East 15622, Udenville, Washington, USA 98072 (622) Inventor Hamad, Ramsey Eff. 94086 Sunnyvale, CA, USA , 240, Balboa Court 1286 (72) Inventor Horn, Stephen Jay United States 94018 El Granada, CA, Pillar Point Harber, Bells Bee 12, Seadancer (no address) (72) Inventor Jacobs, Thomas El. Manoa Way, Linwood, Washington, 98036, USA 14726 (72) Inventor Neogi, Amar United States 98125 Seattle, Washington, USA Buntines Avenue N 12531 (72) Inventor Patel, Mancy, USA 94087 Rembrandt Drive, Sunnyvale, California 1268 (72) Inventor Rose, John Y, USA 94019 Half Moon Bay, California , Terrace Avenue 551 (72) Inventor Scruiser, Mark Es USA 95129 San Jose, California Johnson Avenue 1162 (72) Inventor Warden, David Pee United States 94002 Lion Avenue, Belmont, CA 2103 (56) References JP-A 61-64188 (JP, A) JP-A 56-164598 (JP, A) JP-A 59-171191 (JP, A) JP-A 60-249387 (JP, A) Kai 61-74205 (JP, A) JP 61-141779 (JP, A) JP 56-60092 (JP, A) JP 60-134495 JP, A) JitsuHiraku Akira 63-71574 (JP, U) US Patent 4187339 (US, A)

Claims (22)

[Claims] 1. An apparatus for forming traces between pads on a printed circuit board, the apparatus for extruding a first extrudable material that becomes conductive after curing to form the traces. An extrusion device, a carriage device on which the first extrusion device is mounted, a writing associated with the first extrusion device for injecting and forming the first extrudable material on the printed circuit board A tip, a first guide device for constraining movement of the carriage device in a first linear direction, a base frame for installing the first guide device, a movement of the carriage device in the first direction A second guiding device for constraining in a second orthogonal linear direction, a third guiding device for constraining the movement of the writing tip in a direction orthogonal to the first and second directions, the carriage Device in front A first drive for moving along a first guide, a second drive for moving the carriage along the second, a third tip for moving the writing tip. A third drive for moving along, for controlling the first, second and third drives and for starting and stopping extrusion of material by the first extrusion device, thereby A circuitized lighter including a computerized controller for controlling the starting point, ending point and shape of traces on a printed circuit board, the first guiding device comprising: a pair of substantially parallel rails; A first saddle device slidably mounted on one of the pair of rails, a second saddle device slidably mounted on the other of the pair of rails, the second guide device including the first and second guide devices. Service Fixedly attached to each of the dolly devices to form a trace that includes the second guide device and the first and second saddle devices adapted to move together along the pair of rails. Circuit lighter to do. 2. The parallel rails are smooth steel shafts,
The trace-forming circuit lighter of claim 1, wherein the first and second saddle devices are attached to the rail by linear bearings. 3. The parallel rails are schnaberger (Sc
2. A circuit lighter forming a trace as claimed in claim 1, which is a hnee-burger) rail, said first and second saddle devices being mounted on said rail by means of a Schneberger bearing device. 4. The second guide device includes a pair of substantially parallel rails, the carriage device straddling the pair of rails, the carriage device slidably mounted on each of the pair of rails. A circuit writer forming the trace of claim 1, wherein the circuit writer is formed. 5. The circuit lighter of claim 4, wherein the rail of the second guide device is a smooth steel shaft and the carriage device is mounted on the rail by linear bearings. 6. The second guide device includes a schnaberger rail, and the carriage is mounted to the rail by a schnaberger bearing device.
The described device. 7. Four frame columns arranged in a substantially rectangular shape, a plurality of cable pulleys attached to the frame column, the first and second saddle devices, and the carriage device, At least one adjustable cable anchor in each of the four framing columns, each of the first and second drive arrangements disposed through the plurality of pulleys and locked to the adjustable cable anchors 5. The circuit lighter of claim 4, further comprising a cable system, wherein actuation of the first and second drives causes the carriage to move in two degrees of freedom in a horizontal plane. 8. The first drive device includes a first electric motor installed on the foundation frame, a first cable drum attached to the first electric motor and rotated, and a direction reverse to the cable drum. First and second cables wound around the cable drum and extending from the cable drum toward one side of the circuit lighter; wound in a reverse direction around the cable drum toward the opposite side of the circuit lighter; The circuit lighter of claim 7, including third and fourth cables extending from the cable drum. 9. The first cable passes around the cable pulley attached to the first of the frame column and the cable pulley attached to the first saddle device, and the first cable is adjustable. The cable anchor is locked to a first cable anchor attached to the first frame post, and the second cable is attached to the second cable post of the frame post and the first saddle. Passing around the cable sheave attached to the device and locked to a second cable anchor attached to the second frame post of the adjustable cable anchor, the third cable The cable pulley attached to the third of the frame columns and the cable pulley attached to the second saddle device, and attached to the third frame column of the adjustable cable anchor. Locked to a third cable anchor, the fourth cable passes through the cable pulley attached to the fourth of the frame column and the cable pulley attached to the second saddle device, The adjustable cable anchor is locked to a fourth cable anchor mounted similar to the fourth frame post, so that when the first cable drum is rotated in one rotation direction, the first and second When the second saddle device is urged together in one direction along the first guide device and the first cable drum is rotated in the opposite rotational direction, the first and second saddle devices are 9. A circuit lighter according to claim 8 which will urge together along said second guide device in opposite directions. 10. The adjustable anchor of claim 9, wherein the adjustable anchor is adjusted to exert a substantially equal tensile stress on each of the cables to avoid strain-induced movement of the cables during operation. Circuit lighter. 11. The first and third cables are the first
Since the first and second cable drums are wound side by side from one end of the cable drum, and the second and fourth cables are wound side by side from the opposite end of the first cable drum, the first and second saddle devices are connected to each other. The angle formed by each of the cables with the longitudinal axis of the first cable drum is kept substantially equal while being moved along the guide device to equalize the forces exerted by each cable and the frictional drag experienced by each cable. The circuit lighter of claim 9 which is prone to tendency. 12. The second drive device includes a second electric motor installed on the base frame, a second cable drum attached to the second electric motor and rotated, and the second drive device wound around the cable drum. A fifth cable extending toward one side of the circuit lighter, wound around the second cable drum in the same rotational direction as the fifth cable and extending toward the opposite side of the device. The circuit lighter of claim 7, including a sixth cable. 13. The fifth cable is the first of the frame columns.
One of the cable pulleys attached to the first saddle device, one of the pulleys attached to the first saddle device, one of the pulleys attached to the carriage device, and one of the pulleys attached to the first saddle device. One of the adjustable anchors attached to the second of the stanchions and passing around and the sixth cable of the pulley attached to the third of the stanchions. One, one of the pulleys attached to the second saddle device, one of the pulleys attached to the carriage device, and another one of the pulleys attached to the second saddle device. Around it, it is locked to one of the adjustable anchors attached to the fourth of the frame post, so that when the second cable drum is rotated in one direction of rotation, the carriage Biasing the device in one direction along the second guide and rotating the second cable drum in the opposite direction of rotation causes the carriage to move in the opposite direction along the second guide. 13. The circuit lighter of claim 12, wherein the circuit drive is biased to actuate and the actuation of the first drive device does not move the carriage along the second guide device. 14. The adjustable cable anchor of claim 13, wherein the adjustable cable anchor is adjusted to exert substantially equal tensile stresses on the cable to avoid strain-induced movement of the cable during operation. Circuit lighter. 15. The cables are wound side by side from one end of the second cable drum, the angles of each of the cables with the longitudinal axis of the second cable drum being kept substantially equal to each other. 15. The circuit lighter of claim 14, which produces a tendency to equalize the forces exerted by the cables and the frictional drag experienced by each cable. 16. The first extruding device is a tank device including a supply of the first extrudable material, and the tank device is for extruding the first extrudable material from the extruding device. A gas supply device connected to the tank device for applying pressure to the first extrudable material therein, a flexible tube connection device connecting the tank device and the writing tip, the tank device and the The circuit lighter of claim 1, including a valve device on the flexible tubing connection for terminating the flow of the first extrudable material between writing tips. 17. The gas supply device further includes a pressure control device for controlling an extrusion flow rate of the first extrudable material from the first extrusion device by controlling the pressure, 17. The circuit writer of claim 16, wherein the pressure controller is controllable by the computerized controller in response to programmed information. 18. The valve device includes a rotary valve having an inlet, a through flow passage, and a lateral flow passage from the through flow passage, a third electric motor for rotating the rotary valve, the lateral flow passage. An overflow container connected to the outlet of the flow path, in one position the through flow path does not substantially obstruct the first extrudable material through the rotary valve to the writing tip, When the rotary valve is slightly rotated by the third electric motor, the first extrudable material is allowed to pass through the through-flow passage completely from the tank device. To quickly stop the flow of the extrudable material to the writing tip, and when the rotary valve rotates more, the tank device is moved through the side flow path. Overflow container To relieve the pressure on the write tip from the tank device through the valve to completely eliminate the tendency of the extrudable material to continue to be biased through the write tip. The circuit lighter according to claim 16, including: 19. A fourth electric motor installed on said carriage for raising and lowering said writing tip; engaged with said third guiding device and coupled to said writing tip, together with said writing tip. A slide device adapted to move vertically in the guide device, a shaft driven by the fourth electric motor, wound on the shaft and coupled to the slide device, by the fourth electric motor A thin tongue that allows the slide device to move in the z direction within the guide device with the writing tip as the shaft rotates; the writing tip to move in the z direction according to a preselected instruction. 18. The circuit writer of claim 16, further comprising: the fourth electric motor being controllable by the computerized controller to enable :. 20. The writing tip includes a joint connected to the flexible tube connecting device, a hypodermic syringe tube engaging the joint, and the extrudable material passing through the joint and the hypodermic syringe tube. 17. The circuit writer of claim 16, further comprising: reaching a printed circuit board to form traces on the printed circuit board. 21. The hypodermic syringe-type tubing has an outer slope such that the outer diameter of the tubing at the exit of the extrudable material onto the printed circuit board is less than the nominal outer diameter of the tubing. 21. Having a section such that the width of the extruded trace is narrower than the width without the ramp.
Circuit writer as described. 22. The hypodermic syringe type tube has an inner sloped portion such that the inner diameter of the tube at the outlet where the extrudable material exits on the printed circuit board is greater than the nominal inner diameter of the tube. 21. The circuit lighter of claim 20, wherein the width of the extruded trace is wider than it would be without the ramp.