JPH071825B2 - Rework equipment - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an apparatus for removing a surface mounting device from a circuit board. More specifically, the present invention relates to a multi-nozzle rework apparatus that allows devices of various sizes to be removed without replacing the nozzle.

[Prior Art] Conventional hot gas rework stations are quick and easy for surface mounting on printed circuit boards.
t) Used to attach and remove components from the circuit board. At this time, it does not interfere with surrounding parts or damage the device to be removed from or attached to the substrate. An example of such a conventional system is the Semiconductor Equipment Corporation of Moor park, California, USA.
Model 4460 Hot Gas Rework Station manufactured by T Corporation. This conventional rework system has a complicated device that utilizes one replaceable nozzle through which hot nitrogen gas passes. The hot gas jet of nitrogen needs to be directed to a very limited area so that the surface mount components can be removed without heating adjacent components. For this reason, the apparatus must be provided with a plurality of replaceable nozzles in order to be able to work with surface-mounted components having different dimensions. However, in the conventional surface mounting rework apparatus, it is a reality that nozzles of different sizes that can be exchanged are necessary so that an operator can move or replace devices of different sizes on a printed circuit board. .

Hot gas rework tools are disclosed in many prior art patents listed below.

Broten, Other US Patent 4,295,596 Fanene US Patent 4,366,925 Beck US Patent 4,426,571 Zovko, Other US Patent 4,552,300 Slack, etc. US Pat. No. 4,602,733 Fridman US Pat. No. 4,605,152 Holdway US Pat. No. 4,620,559 Green US Pat. No. 4,696,096 The nozzle, or similar gas directing device, must be replaced in order to work on it. The above-mentioned patents are representative of conventional equipment which requires nozzle replacement to remove and / or reattach different sized surface mounting devices using precision hot gas technology.

Therefore, the present invention improves upon conventional devices by providing multiple nozzles. The nozzle reciprocates to accurately direct the hot gas to the bonding location of the surface mount device. In the present invention, it is not necessary to have a large inventory of nozzles of different sizes, and no time is wasted replacing nozzles.

SUMMARY OF THE INVENTION The present invention provides a universal rework apparatus that allows quick and accurate removal and reattachment of surface mounting devices of virtually all sizes and styles without replacing the nozzle. ing. Surface-mounted devices mounted on printed circuit boards or similar boards have epoxy-bonded templates (di
e), eutectic bonded templates and leadless chip carriers. Of these, the leadless chip carrier is particularly often used. Like a conventional hot gas rework system,
Also in the apparatus of the present invention, it is preferable to use nitrogen gas which is accurately and slowly guided to the joining position. Gas temperature is usually 80
Up to 0 ° C. By providing a plurality of nozzles, the device of the present invention can exhibit multiple functions not available in conventional devices. The multiple nozzles allow reworking of surface mount devices having various sizes and shapes. In prior art devices, rework could only be done by replacing a number of nozzles having different styles and shapes. By using a multi-nozzle mechanism (usually four nozzles, each nozzle reciprocating substantially along each side of an imaginary rectangle), the device of the present invention can be moved to a specific position. The hot hot gas can be conducted to remove and reattach surface mount devices mounted on the substrate. At this time, the adjacent device is not overheated and the device on which the work is being performed is not damaged. The device of the present invention can perform the above-mentioned operations without wasting time to replace nozzles having different shapes. In the conventional apparatus, it is necessary to use nozzles having different shapes in order to perform rework on devices having different shapes and sizes. Therefore, the use of the apparatus of the present invention eliminates the downtime required for nozzle replacement, which was necessary in the conventional apparatus. Users of the rework machine according to the present invention do not have to stock nozzles of various sizes and shapes as in conventional machines, and work on all surface mount devices. It can be carried out.

OBJECTS OF THE INVENTION Accordingly, a primary object of the present invention is to obstruct or damage adjacent devices when working on surface mount devices of various styles, sizes and shapes. It is an object of the present invention to provide a surface-mounting rework apparatus that enables quick and easy removal and replacement of a surface-mounting device without using the device.

Another object of this invention is the use of multiple nozzles arranged to direct low velocity hot gas to the junction of the surface mount device end, and rework to devices on printed circuit boards or similar substrates. To provide a rework device for surface mounting that facilitates

Still another object of the present invention is to prevent damage to a device to be operated or an adjacent device,
Further, when working on devices having different sizes and shapes, there is no need to perform time-consuming nozzle replacement, and further, there are various types that need to be replaced on the rework apparatus according to the size and shape of the device to be reworked. It is an object of the present invention to provide a multifunctional multi-nozzle surface mounting rework apparatus that enables reworking of surface mounting devices without having to keep an inventory of nozzles having various sizes and shapes.

Other objects and advantages of the present invention will be apparent from the embodiments of the present invention described below.

[Embodiment] An embodiment of a rework apparatus according to the present invention will be described below with reference to the accompanying drawings. The surface mount rework system according to the present invention is capable of using a number of subsystems of the Model 4460, a surface mount rework system manufactured by Semiconductor Equipment Corporation of Moore Park, Calif., 93021, USA. Very similar to the Model 4460. As an example, model 4460, like other devices, includes a device for heating the gas to a temperature sufficient for use in a rework system, and a device for directing the heated gas to a nozzle. As another example, conventional devices are equipped with video cameras, video monitors and similar devices for observing working positions. These subsystems are similar to the subsystems used in this invention. The electronic and vacuum devices used in conventional equipment, such as the Model 4460, and which can be used in the present invention, are conventional and do not form a new feature of the apparatus of the present invention. Therefore, the operation of these conventional subsystems will not be described here. Those skilled in the art will immediately understand the operation and use of such subsystems in embodiments of the present invention.

A description will be given with reference to FIGS. 1 and 2. A multi-nozzle surface mounting rework device according to the present invention, represented by reference numeral 10, comprises a control console 12 and a working monsole 14. The work console 14 has a member for movably supporting a housing 18 having a nozzle assembly 16 therein in a part of the console 12. The nozzle assembly 16 has a plurality of nozzles, preferably four nozzles, but the nozzle assembly 16 will be described in more detail. The nozzle assembly 16 enables the rework apparatus 10 to rework virtually all styles and shapes of surface mount devices without the need for nozzle replacement that was required in the prior art. The rework machine 10 allows for immediate adjustment of the nozzle assembly 16, from smaller 0.1 inch (2.54 mm) to larger 2.0 inch (5.
Supports any size surface mount device up to 08 cm. The rework apparatus 10 can accommodate not only square surface mount devices, but also rectangular surface mount devices, and devices with contacts on one side, two sides, or four sides. These functions can be performed without removing or replacing the nozzle. When it is necessary to apply the rework apparatus to surface mounting devices having different sizes and shapes, the rework apparatus 10 is driven by a motor with a video display to process the devices having the respective styles and shapes. Is reset via the control device. The adjustment at this time can be performed in a few seconds as described later.

The board holder 20 is a surface-mounting device to be reworked, that is, a surface-mounting device (not shown) that is removed or replaced by accurately guiding low-speed hot gas to the joint portion to perform detachment and joining. It has a shape capable of holding the printed circuit board placed thereon. Board holder 20 is a nozzle assembly
It forms part of a two-position work surface 36 located just below 16.

As will be described in more detail below, an optical system having a video camera 24 and a video monitor 26 allows an operator of the rework apparatus 10 to observe the work area. Image splitter 22 not only allows you to see the surface mount device being reworked,
As will be described later with reference to FIG. 4, the nozzle assembly 16
Can be observed at the same time. Since conventional rework machines also use video equipment to facilitate the work of surface mount devices, the structure and operation of the video equipment will not be discussed in detail here.

A vacuum pickup 30 is provided in the center of the nozzle assembly 16 so that the device can be operated without damaging the surface mount device. The vacuum pickup 30 will be described in detail with reference to FIG.

A preparation station 28 is provided on the work console 14 adjacent to the work surface 36. The preparation station 28 is optional and similar structures have been used in conventional equipment.

A status panel 32 is arranged on the front surface of the control console 12 so that the state of the nozzle assembly 16 can be immediately determined. Control of the nozzle assembly 16 is performed via a keypad 38 provided at a position on the work console 14 that is easily operated by the user. The work console 14 is also provided with a position control 34 so that the X, Y and θ positions of the board holder 20 can be controlled. The particular mechanism used to position the printed circuit board by the board holder 20 and the electronic devices used to control the rework device 10 are conventional. Therefore, the structure and function of these conventional devices need not be described in detail and will be omitted.

Next, description will be given with reference to FIG. 2, FIG. 3, and FIG. As can be seen, the nozzle assembly 16 has a nozzle 40. The low velocity hot gas is accurately directed through the nozzle 40 to a location along the edge of the surface mount device 46 that is reworked in accordance with the present invention. Only two nozzles 40 are shown in FIGS. 2, 3, and 4 to facilitate the description of the image splitter 22 and the vacuum pickup 30. In the embodiments of the invention described below, four nozzles 40 are used to provide maximum versatility in reworking surface mount devices of various sizes and shapes.

The vacuum pickup 30 has a vacuum tube 42. The vacuum tube 42 has a contact head 44 at its end, and the outer end of the vacuum tube 42 is conventionally connected to a vacuum source (not shown). The vacuum tube 42 has a curved shape or is bent so that the view of the surface mounting device 46 on the board holder 20 and the nozzle 40 with respect to the video camera 24 is not obstructed. When the device 46 is removed, the vacuum supply source is driven with the vacuum pickup 30 lowered above the device 46. Once hot gas from nozzle 40 causes reflow of bonding material, device 46
Is lifted from board 47. An assembly 48 biased by an adjustable spring on the front end of vacuum tube 42 facilitates lifting of device 46 just when reflow occurs. The fact that the vacuum tube 42 has a curved shape or is meandered in that the operator of the rework device 10 can immediately see the device 46 and nozzle 40 with little obstruction by the video monitor 26. It forms an important feature of the invention. When the surface mounting device 46 is lifted by the vacuum pickup 30, the nozzle assembly 16 is retracted upward, and a space is provided through which the board holder 20 can be taken out from under the nozzle assembly 16 to facilitate inspection and cleaning. Contact heads 44 having various sizes can be exchanged on the end surface of the vacuum tube 42, and the vacuum pickup 30 can be used for various size parts including very small parts.

As seen in FIGS. 2, 3, and 4, the image splitter 22 is retractably disposed between the tip of the nozzle 40 and the surface-mounting device 46 to be reworked. The image splitter 22 essentially consists of a mirror for splitting the image. This mirror allows you to see the lower device 46 as well as the upper nozzle 40, and these two screens are superimposed and displayed on the video monitor 26. Therefore, the user of the rework apparatus 10 needs to use the device 46 to be removed or installed.
Both the nozzle 40 and the nozzle 40 can be observed simultaneously, and the nozzle 40 can be reliably aligned with the device 46. This observation is made when the nozzle assembly 16 is in the raised position. As the image splitter 22 is continuously retracted and the nozzle assembly 16 is lowered, the nozzle 40 and surface mount device 46 are accurately aligned. The sweep range and nozzle position of the nozzle 40 (see page 20) can be adjusted by the nozzle assembly 16 in the raised position, and once the alignment is done using the image splitter 22, it also adjusts for the moving nozzle. be able to.

The board holder 20 holds a printed circuit board such as the board 47 or a similar board for reworking. When the board 47 is roughly aligned and locked in the board holder 20, the board 47 is finely adjusted in X, Y and θ positions using the fine adjustment knobs provided by the position control 34. . As best seen in FIG. 2, the knob assembly 50 allows the board 47 to be locked in an approximate position.

Although not shown in the drawings, the rework apparatus 10 may be provided with a "backside" heater to prevent thermal shock to surface mounting devices on the board, such as board 47. Backside heaters have long been used in systems such as the Semiconductor Equipment Corporation model 4460 described above. The backside heater has a timing function of urging the operator of the rework device when the preheating cycle ends, and efficiently controls gas flow and temperature. The backside heater is fixed at a very close position below the board 47, and the heater is mounted in the working console 14 directly below the board holder 20. The amount of thermal energy applied to preheat the board 47 is controlled by conventional gas flow and temperature controls (not shown). Next, description will be given with reference to FIG. 5, FIG. 6, and FIG. In the exemplary embodiment, nozzle assembly 16 has four nozzles 40. Nozzle 40 delivers precisely slow velocity hot gas to a location along the edge of a surface mount device, such as device 46 as seen in FIG. 5 and 6, each of the nozzles 40 reciprocates along each side edge of the device in the area in which the surface mounting device 46 is to be removed and remounted on the board 47. To do. In order to operate the rework device 10 properly, heating gas such as nitrogen to an extremely high temperature,
It is important to concentrate the available thermal energy in the gas to the location where the bonding material is melted. Nozzle assembly 16 to facilitate proper application of slow hot gas
Must be positioned exactly up and down in position. To make nozzle 40 easier to see, nozzle 40
Is tilted in the direction of about 30 ° with respect to the vertical in FIG. 5, but a practically preferred angle range is 18 ° -20 °. As can be seen in FIG. 12, the four nozzles 40 each have two degrees of freedom of movement with respect to the surface mounting device 46. The distance each nozzle 40 travels along the edge of device 46 will be referred to as the "sweep range," and the proximity of each nozzle 40 to device 46 for surface mounting will be referred to as the "nozzle position." For convenience of explanation,
Each nozzle will be referred to as a right, left, front, and back nozzle 40. In operation, left nozzle 40 and right nozzle 40
Are electrically connected so that the “sweep range” of the left nozzle 40 and the “sweep range” of the right nozzle 40 are changed at the same time. Therefore, the sweep range of both the left nozzle and the right nozzle can be controlled by adjusting one. Similarly, the front nozzle 40 and the rear nozzle 40 are electrically connected, and both nozzles can be controlled by adjusting one. Further, each pair of nozzles 40 described above can be connected so that one "nozzle position" changes at the same time as the other "nozzle position". Also, all nozzles 40 can be connected to allow for quick alignment in terms of both position and sweep range when dealing with surface mount devices 46 having square shapes. When removing or reattaching a device 46 that has contacts on only two sides, each nozzle pair, i.e., the left and right nozzles, or the front and back nozzles, may be retracted or left inoperative. it can. Furthermore, the "in line" on the substrate
A single nozzle 40 can also be used to remove and replace components or very small components.

The nozzle sweep cycle is the same. The sweep cycle refers to the time required for the nozzle 40 to descend the contact row of the device 46 and return to its original nozzle position. Therefore, matching reflow time and balancing heat input on adjacent sides of a square device requires separate gas temperature and gas flow controllers. That is,
It requires one set for the left 40 and right 40 nozzles and another set for the front 40 and back 40 nozzles. When working on surface mount devices that have contacts on only two sides, either controller can be shut down completely. When initially operating the rework machine, all four nozzles can be raised to a constant idling (rest) temperature for faster response. A timer (not shown) may be provided on the associated heating device to provide a constant cycle duration and prevent overheating.
As mentioned above, the device by vacuum pickup 30
Upon raising 46, the nozzle assembly 16 retracts upwards and the heating device returns to idle temperature. A pressure interlock (not shown) can also be provided to prevent the heater from burning out when the gas pressure is low.

Next, description will be given with reference to FIGS. 5 and 6. Nozzle 40
Are arranged in the directions corresponding to the left, right, front, and rear pairs shown in FIG. The movement of the nozzle 40 pairs in the "sweep range" mode is performed by the gear motor 5 connected to the sprockets 54 and 56 and the idler pulley 58 by the cable 60.
Driven by 2. Manual adjustment of the sweep range
Controlled by the range setting knobs 62,64 in cooperation with the sprockets 54,56, the nozzle 40 is controlled to the sweep range required for a given rework situation. The position of the nozzle 40 is
Controlled by two cable and pulley assemblies 66,68. Cable and pulley assemblies 66,68 are turnbuckle adjusters 70,7 for maintaining cable tension.
Having 2. Each cable and pulley assembly 66,68 has a return spring 74,76 that returns the nozzle 40 to its original position set by a thumbscrew 78.

Each nozzle 40 is retained within a nozzle mounting assembly 80. Assembly 80 is mounted so that it can reciprocate to perform the sweep range function described above. A small stepping motor to move the nozzle 40.
An electric motor (not shown), such as a motor, can be used. These electric motors make an electrical connection to properly position the nozzle 40. The nozzle 40 can be controlled by a device other than the above-mentioned device.

This will be described with reference to FIG. The status panel 32 essentially consists of a planar switch / display panel for displaying the status of the nozzle 40. Further, the rework device 10 can be controlled via the status panel 32. As an example, an indicator of the function of the device can be flashed to display the status of the device. Also,
The position of the nozzle 40 can be illustrated and the status of gas flow to the nozzle can be displayed on the status panel 32.

As described with reference to FIGS. 8 and 9A-9D, the nozzle 40 pair can be controlled via the link control panel 82. Sweep range panel 84 is shown in Figures 9A and 9B.
In the figure, it consists of a pair of flashlights showing the connection of the left and right nozzles and the front and rear nozzles. Both nozzle pairs can be connected so that all of the lights 86 are illuminated alternately or simultaneously depending on the particular connection of the nozzle 40 pairs. Similarly, the nozzle position is displayed by the nozzle position display 88 including the light 90.

Next, description will be given with reference to FIG. 10 and FIG. In this embodiment, the nozzle 40 includes inner and outer heat shields 9
Held within 2,94. The nozzle 40 is heated by a heater 96 capable of displaying heat by a thermocouple 98. The position of the nozzle 40 within the heat shield is adjusted by a spring biased adjustment knob 100.

The embodiments described above can be implemented in any form without departing from the spirit and scope of the invention.
Features not detailed in the mechanical and electrical subsystems make up a conventional ready-to-use subsystem. These subsystems include gas heating subsystems, electronic control subsystems,
Includes backside heating subsystem, vacuum subsystem, etc. The invention, in its most basic form, is independently for directing the slow hot gas precisely into place for removing and reattaching surface mount devices on a substrate such as a printed circuit board. It is provided as a surface mounting rework device having a large number of nozzles that can move on coordinates.

[Brief description of drawings]

The drawings show an embodiment of a surface mounting rework apparatus according to the present invention. FIG. 1 is a perspective view of the surface mounting rework system, FIG. 2 is an elevation view of the apparatus shown in FIG. FIG. 4 is a partial elevation view of the vacuum pickup subsystem of the apparatus, FIG. 4 is an elevation view of an optical device used to make the rework position easy to see, FIG. 5 is a plan view of a multi-nozzle device, and FIG. 5 is a sectional view taken along line 6-6 of FIG. 5, FIG. 7 is a view showing a flat switch / display panel used for controlling the device, and FIG. 8 is a view showing a display panel used for controlling the device. , Fig. 9A, Fig. 9B
FIGS. 9C and 9D are views showing combinations of indicators for displaying the sweep range of the nozzle on the display panel shown in FIG. 8, FIG. 10 is a partial cross-sectional view of the hot gas assembly, and FIG. 11 is hot. FIG. 12 is an elevation view of the gas assembly, and FIG. 12 is a view showing positions of some nozzles when reworking the surface mounting device. 12 …… Control console 14 …… Work console 16 …… Nozzle assembly 18 …… Housing 20 …… Board holder 22 …… Image splitter 24 …… Video camera 26 …… Video monitor 30 …… Vacuum pickup 32 …… Status Panel 34 …… Position control 38 …… Keypad 40 …… Nozzle 42 …… Vacuum tube 44 …… Contact head 46 …… Device 47 …… Board 48,80 …… Assembly 50 …… Knob assembly 52 …… Gear motor 54, 56 …… sprocket 58 …… idler pulley 62,64 …… range setting knob 66,68 …… cable / pulley assembly 70,72 …… turnbuckle adjuster 74,76 …… return spring 82 …… link control panel 84 ...... Sweep range panel 86,90 …… Light 88 …… Nozzle position display 100 …… Adjustment knob

Claims (5)

[Claims] 1. A rework apparatus for removing or mounting a device by applying heated gas to at least one edge of the device for surface mounting on a substrate to melt the bonding material in that part. A nozzle assembly having a plurality of nozzles through which heating gas is passed, and a moving device for moving the nozzle along the corresponding side edge of the device to apply the heating gas to the bonding material. And a rework apparatus configured to be positionable with respect to a corresponding portion of the device so that each of the nozzles blows heated gas toward each bonding portion of the surface mounting device. 2. The surface mounting device is rectangular and the nozzle assembly has four nozzles, each nozzle adapted to be moved along one side edge of the device. The rework apparatus according to the first aspect of the invention. 3. A rework apparatus for a device having different side edge dimensions, the moving apparatus having a device for controlling a proper proximity position of a nozzle with respect to the device and a moving distance along a side edge of the device. The rework device according to claim 1, which can be used. 4. A rework machine for use with devices having different side edge dimensions, wherein the mover has means for controlling the distance traveled by each nozzle along the side edge of the device. The rework device according to claim 1. 5. The moving device comprises a device for simultaneously controlling the distance traveled along the corresponding side edge of each pair of devices of a pair of nozzles oppositely disposed with respect to one device, and having different side edge dimensions. The rework apparatus according to claim 1, wherein the rework apparatus can be used for the device.