JPH0145957B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD This invention relates to soldering techniques, and more particularly to short-time pulse soldering methods and apparatus suitable for automatic wiring installations. Circuit board manufacturing technology for interconnecting electronic components has developed dramatically in recent years. Advances in integrated circuit technology, in particular, have encouraged greater densification of electronic circuits, which in turn has required denser, more reliable circuit boards for interconnecting electronic components. According to one successful technique, dense circuit boards are formed by wire drawing onto the board using extremely fine insulated copper wire. These wires are placed according to a computer program. The wire pattern is then encapsulated and the ends of the wires are connected to terminal pads on the board. This technique is outlined in US Pat. Nos. 3,674,602 and 3,674,914. One of the key advantages that wire-drawn circuit boards have over conventional printed circuit technology is that by crossing insulated wires together, extremely high density connections can be obtained within a single layer. This eliminates the need for interlayer connections. Traditionally, connections to terminal pads on wired circuit boards have been made by plating. That is, after the wire pattern is placed and encapsulated, holes are formed in the circuit board at appropriate locations and the holes are plated. This hole plating is carried out in such a manner that not only the holes are plated and the terminal pads are formed, but also the tips of the insulated wires exposed through the formed holes are electrically connected to the terminal pads. Of course, soldering techniques are techniques that have been used for a long time to connect wires to terminals. However, this soldering technique
It is not considered useful in automated high-speed manufacturing processes for circuit boards. This is due to the difficulty of positioning the soldering, the need to avoid thermal shock to the plastic substrate, and the risk of solder flowing into the holes associated with the terminal pads. Conventional attempts to solve these problems include the following. (a) Forming a soldering pad that provides a narrow heat transfer restricted area between the solder area and the plating hole (as described in U.S. Pat.
No. 3673681). (b) Forming an electrically conductive and thermally resistant nickel layer in the soldering area (as described in the above-mentioned U.S. Pat.
No. 3673681). (c) Cooling the soldering area with a stream of inert gas (see U.S. Pat. No. 3,673,681, supra, and U.S. Pat.
issue). (d) By pre-stripping and cutting the insulation of the wire segments to be soldered, the high temperature treatment normally required to strip the insulation during soldering is omitted (U.S. Pat. No. 4,031,612 to Nicholas). . (e) Using a parallel gap soldering technique that uses solder pads to complete the heating circuit and generates heat on the solder side (U.S. Pat. No. 3,444,347 to Maltier). (f) Taking temperature measurements to control heating electrical circuits to control the amount of heat generated (U.S. Pat. No. 3,778,581 to Denny). By using a combination of the above techniques,
Although it is possible to perform complete soldering,
These techniques do not provide a system that can tolerate various changes in conditions in general manufacturing techniques. Also, some of the prior art methods described above are often relatively costly and complex to operate, or reduce the surface area for wiring circuitry on a circuit board. According to the present invention, a hardware mechanism is provided that combines various conditions for soldering extremely fine insulated wires to terminal pads. This mechanism may damage the circuit board or plating holes,
It operates in response to varying conditions in common manufacturing techniques without requiring a particular circuit board shape or significantly increasing cost. A basic aspect of the invention is to control the peak temperature of the soldering iron and the amount of heat generated thereby during soldering. The amount of heat is a function of the temperature of the soldering iron, the mass or size of the soldering iron, and the time to which thermal energy is supplied.
The amount of heat is adjusted to be sufficient to provide reliable soldering under specific ambient conditions. It is important that the amount of heat does not exceed the required value. The peak temperature applied to the soldering iron during operation is preferably 538°C (1000°), and preferably within 872-1093°C (1600-2000°). These high temperatures are sufficient to evaporate or sublimate the insulation to expose the copper surface of the wire for soldering. Furthermore, if the amount and timing of heat are controlled, it is possible to achieve a steep temperature gradient that limits the temperature to only those regions that are effective for insulator evaporation, sublimation, and solder melting, thereby avoiding dangerous This is to avoid high temperatures. By controlling the amount of heat applied and the duration of the energy application, the wire insulation can be removed before heat transfer occurs that would cause damage to surrounding circuit boards, insulated wires, or terminal pads. Can be peeled off and soldered. According to the technique according to the invention, the soldering time is less than 500 msec, preferably shorter than 50 msec. Under reasonable conditions and equipment, the peak temperature for insulation evaporation of the wire exceeds 399°C (750°C) within a time period of less than 50 msec and the peak temperature for soldering the wire to the terminal pad. The solder connection can be completed when the temperature exceeds 232°C (450°), but the temperature of the board adjacent to the terminal pad does not exceed 288°C (550°). By controlling the amount and timing of heat supply during the operation, high temperature insulation removal and soldering can be accomplished and the heat can be used up before heat transfer to hazardous areas occurs. A soldering device according to the invention is shown in FIGS.
It can be incorporated into an automatic circuit board wiring system as shown in the figure. Complete details of this device are disclosed in US Pat. Nos. 3,674,602 and 3,674,914. The circuit board 5 is movably supported by an X-Y feeder 40, and is moved between two points according to a computer control device 42. The wire guide device 10, the wire drawing iron 20, and the soldering iron 30 are mounted on the circuit board so that they can rotate as a unit. The insulated copper wire 11 is supplied to the iron pen 20 via a wire guide, and the iron pen coats the adhesive surface coat 6 on the circuit board.
are crimped and disposed as best shown in FIG. The rotational position of the wire pulling device (including the wire guide 10, iron pen 20 and soldering iron 30) is set according to the direction of table movement, and the wire is thereby moved onto the substrate surface moving away from the wire drawing device. It is laid down. The soldering iron is rotatably supported on pivot 31 and can be moved up and down by a suitable solenoid or pneumatic actuator 48. The tip 32 of the soldering iron occupies a position spanning the laid wire at the soldering position where the soldering iron has descended. This allows the soldering operation to occur normally, while the table remains stationary at a point that positions the wire in the area of the terminal pad to which it is to be connected. The terminal pads are preferably pre-tinned and the application of appropriate heat will evaporate the insulation and complete the soldering. A position detector 44 is attached to the X-Y feeder 40 to detect the table position to determine whether it is in a proper position during the soldering operation. If it is in the proper position, computer control 42 generates an activation signal for solenoid control 49 and timer control 46. Solenoid control device 4
Reference numeral 9 is connected to a solenoid 48, which raises and lowers the soldering iron 30. A large current power supply 52 is connected to the soldering iron 30 via a switching circuit 50.
is connected. The switching circuit is controlled by a timer control device 46. The timer control device 46 generates one or more large current pulses having a predetermined amount of energy and supplies them to the soldering iron called by the computer control device 42. Details of the tip 32 of the soldering iron, which straddles the wire 11 and is located above the terminal pad, are shown in the third section.
As shown in the figure. The terminal pads can be formed by pressing tin-plated hollow copper terminals into appropriate locations on the circuit board 5, or by using printed circuit techniques for perforations in the copper plate and subsequently plating the plating surface. The formed terminal pad 53 has a cylindrical body portion 5 passing through the hole in the plate.
4 and a surface flange portion 55. The tip 32 of the soldering iron has a roughly U-shaped cross section,
The U-shaped bridge accounts for the effective mass of the tool. Chip 32 preferably consists of a tungsten alloy that has been slightly oxidized at high temperature. In some cases it may be necessary to carry out the soldering in an inert atmosphere to avoid oxidation of the soldering iron. The bridge of the soldering iron preferably has a group on its lower surface, which group contains the wire 11 to be soldered.
It is sized to be partially retractable so as to maintain it in a favorable heat transferable contact relationship.
The effective mass (effective mass) of the soldering iron is determined by the width being "W" between the legs 34 and 35 of the chip, the length being "L" in the direction of the wire, and the height. is indicated by the height "H" of the bridge. Bridge legs 34 and 35 are integrally formed with support arms 36 and 37 held within a suitable support structure 38 (see FIG. 1). A typical soldering process is shown in FIGS. 4 and 5. The hole passing through the body portion 54 of the terminal pad 53 has a diameter of 1.02 mm (0.04 in.), and the flange 55 has a diameter of 1.02 mm (0.04 in.).
The radial length of is 0.38 mm (0.015 in.), and the outer diameter of its flange is 1.78 mm (0.7 in.). The flange has a thickness of 0.05 mm (0.002 in.).
Insulated wire 11 consists of a 0.102 mm (0.004 in.) diameter copper wire surrounded by 0.013 mm (0.0005 in.) thick insulation. The solder layer has a thickness of approximately 0.038 mm (0.0015 in.). The solder band 56 for joining the wire with the insulation removed to the terminal pad is approximately 0.381 mm.
(0.015in.) wide and approximately 10.16mm (0.040in.) long. The solder for soldering is preferably provided by a solder coating on the tinned or plated (non-eutectic) terminal pads described above. Optionally, the wire can also be solder coated as a solder source for soldering.
Other techniques for applying solder can also be employed. For example, it is also possible to spray powder or paste solder onto the soldering area, to place solder in the form of washers, discs or ribbons in the soldering area, or to use micro-shaped solder. According to the present invention, the amount of heat used in the soldering operation is carefully controlled. The amount of heat depends on the effective mass of the soldering iron, the temperature of the soldering iron, the energy supplied during the soldering process, and the mass of the wire and copper foil forming the terminal pads on the circuit board. The temperature of the tip of the soldering iron is further controlled to obtain a desired temperature curve in which maximum heat energy is used to complete the soldering and minimal heat transfer occurs in the heat sensitive plate areas. When constructing circuits by point-to-point wiring, time efficiency is a very important factor in achieving an effective wiring machine, so the various device operating conditions are selected to achieve rapid soldering. The selected conditions must allow the device to form good soldered connections regardless of the wiring structure on the circuit board. There are various sizes of terminal pads in common circuit board processing, but in most cases they are set to a reasonable size according to the board surface. The size of the copper portion in the soldering area affects heat dissipation and heat transfer. According to the present invention, conditions can be selected to provide desirable soldering under a wide variety of conditions commonly experienced on circuit boards. The effect was confirmed by using soldering irons of different sizes and energizing the soldering irons at different energy levels and for different time periods to obtain a reasonable combination of conditions.
The results of these tests are summarized in the table below.

[Table] As shown in Figure 3, the dimensions of a soldering iron consist of width, height, and length (W x H x L), and have an associated effective mass. Therefore, for example, the dimensions in the first row of the table, i.e. width 0.559 mm
(0.022in.), height 0.305mm (0.012in.) and length
For 0.508 mm (0.02 in.), the total effective mass is 86.59 cm ³
( ^5.28in3 )× ^10-6 . The voltage applied to the soldering iron is
At 4.25V, the result is a current of 175A. In order to perform tests over a range of conditions such as those experienced in typical circuit board processing, these tests were performed on relatively small terminal areas forming a 0.762 mm (0.03 in.) wide strip and 25.4 mm (1 in.) wide strips. ) was implemented on a standard circuit board using a relatively large terminal area forming a strip of width. Tests on these strips have a 30:1 ratio in width and are compatible with substrate conditions under normally expected conditions. The test was determined by applying various soldering times and then visually inspecting the soldered area. The conditions under which favorable soldering was obtained are listed in the table. For example, looking at the second row of this table, a soldering iron applying an effective mass of 86.59cm ³ (5.28in ³ ) × 10 ^-6 is applied with 6.4V;
It shows that a current of 250A flowed. 0.762
On relatively small pieces, 0.03 in. (mm) wide, favorable solder joints were formed using energization times of 11 to 14 msec. With relatively short energization times (in this case less than 11 msec), an insufficient amount of heat is generated for insulation removal and suitable soldering. Relatively long energization times (in this case longer than 14 msec) will damage the wire insulation or substrate outside the solder area.
Tests conducted on relatively large pieces (25.4 mm wide) examined whether soldering was performed properly using an activation time of 12 to 23 milliseconds. Therefore, using this specific size soldering iron within the range of 12 to 14 msec will change the terminal pad size from 0.0762 mm (0.03 in.) to 25.4 mm (1 in.).
Desirable soldering can be performed regardless of the terminal pad size. The temperature of the tool was determined visually by monitoring the color temperature, from which the corresponding temperature was determined. In the second row of the table, the temperature of the soldering iron is 999℃ at the observed bright color.
(1830〓). This test establishes the conditions that should be selected to form a satisfactory solder joint within the range of conditions experienced in normal general processing. As shown in the second and third rows of the table, the mass of the soldering iron is relatively small (corresponding to an effective mass of 86.59cm ³ (5.28in ³ ) × 10 ^-6 ), and the soldering iron is 6.4V or 8.6V applied
If 250A or 275A flows, there will be an energization time that satisfies the full range of plate conditions.
When a lower voltage of 6.4V (corresponding to a current of 250A) is applied, a 12-14ms energization time will result in a chip temperature of 999°C (1830°C) and the preferred soldering over the entire range of terminal pad sizes. is formed. 8.6V which is also a somewhat higher voltage than this
(corresponding to a current of 275A) is applied, then 6
~8 seconds energization time is 1093~1204℃ (2000~2200℃)
Provide a corresponding soldering iron temperature of 〓), which will produce a favorable solder joint over the entire area of the terminal pad. As is clear from the table, under these conditions the range of terminal pad sizes is relatively narrow and all terminal pads are formed to uniform dimensions, but other conditions must also be met in order to form a satisfactory solder joint. It will be found again. In all cases the energization time is less than 500 msec, thus providing a rapid soldering technique useful in automatic machines. Satisfactory soldering in most cases is 150
This was achieved in a time shorter than milliseconds, especially within 50 milliseconds. Although in some cases preferred soldering has been achieved at low soldering iron temperatures, generally the soldering iron temperature is higher than 538°C (1000°), preferably 872-1093°C (1600-2000°).
It should be carried out within the range of 〓). Low soldering iron temperatures will require relatively long soldering and heating times, resulting in relatively large heat transfer to the circuit board. Generally, relatively high temperatures provide relatively steep temperature gradients with low heat transfer and relatively short energization and contact times. However, 1093℃
(2000〓) Higher temperatures are not preferred as this leads to rapid deterioration of the soldering iron. Figure 6 shows temperatures above about 538℃ (1000〓) and about
This shows a typical temperature curve when a soldering iron temperature of up to 760°C (1400°) is obtained. Tip 62 of soldering iron 58 connects insulated wire 68 to copper foil terminal pad 6 located on plastic circuit board 65.
4 Press it onto the top. The insulated wire is shown with the insulation removed in the soldering area. The wires are soldered to the copper foil pads by solder strips 56 shown in FIGS. 4 and 5. 760℃ (1400
〓) soldering temperature is size 0.559×0.406×
It is provided by energizing a 0.508 mm (115.46 x 10 ^-6 cm ³ ) soldering iron with a voltage of 6.5 V (current of 250 A). This provides an activation time of 22 milliseconds which provides a good solder to the pad within a diameter of 1.78 mm (0.07 in.). The soldering iron first erases the insulation by evaporating it from the wire. The remaining insulation outside the solder area reaches a maximum temperature of approximately 371°C (700°C). The temperature of copper wire is 399℃ (750〓), which is about 482℃ (900〓), that is, 260℃ from the peak temperature of the soldering iron.
The temperature rises to a level that has dropped by about (500〓). Also,
Solder has a melting point above 232°C (450°), usually about
The temperature rises to 277℃ (530〓). This temperature is about 188℃ (370〓) lower than the copper wire temperature. The copper terminal pad temperature will be close to the solder temperature. The pad temperature typically reaches a peak value of about 260°C (500°), which is about 17°C (30°) lower than the solder temperature.
Stay at a safe temperature below 288℃ (550〓).
Plastics in circuit boards are typically around 249°C.
(480〓), which is about 11℃ (20〓) lower than the pad temperature, so it must be maintained at a safe temperature below 288℃ (550〓), which could damage the board etc. Ru. Most of the solder in the hollow part of the terminal pad will be below the temperature of approximately 177°C (approximately 350°C), which is the melting point of the solder, 232°C (450°C).
〓) Maintained below. Temperature curves are critical to providing high temperature and energy characteristics for insulation stripping and soldering without creating damaging overheating conditions within the terminal pad cavity or on the circuit board. . Relatively high solder iron temperatures (and relatively short energization periods) tend to create relatively steep temperature gradients, thus allowing large amounts of heat to be produced without significant temperature increases in areas where damage may occur. to the soldering area. The selection of conditions is particularly important, so that only slightly more heat is supplied than is required for effective soldering, and that the supplied heat is almost used up in forming the solder joint, preventing damage. They are prevented from moving into areas where they will be exposed to. In carrying out the process, the heated soldering iron first contacts the insulated wire, where a relatively small thermal conduction is created. After the insulation has been broken down, the soldering iron contacts the copper wire and the thermal resistance of this contact is reduced to a significant extent. At this point, the wire in contact with the soldering iron is heated and the insulation between the wire and the terminal pad is evaporated away. The amount of heat remaining after the insulation is removed must be sufficient to melt the solder and form the solder joint. 371℃ for removing insulation
(700〓) is required, but temperatures higher than 232℃ (450〓) are sufficient to melt the solder. The energy supplied to the soldering iron should be direct current or high-frequency alternating current, with a current in the range of 50-500 A and a pulse width of 5-500 msec if only a single electrical pulse is used in soldering. must be kept within. As already mentioned, the two basic factors controlled according to the present invention are the tool temperature and the amount of heat applied to it. Generally, the tool temperature must be as high as possible, which will accelerate deterioration of the soldering iron. The amount of heat delivered to the soldering area is a function of the soldering iron temperature, the effective mass of the soldering iron, and the energization period, and may be only slightly more than the amount of heat required to evaporate the insulation and complete the soldering. . This objective is achieved by constructing a soldering iron with a predetermined mass and bringing it into contact with the wire to be soldered within a predetermined period of time, during which time the soldering iron is energized and controlled by passing a current through it. Adequate control of the amount of heat applied is achieved by preheating a soldering iron of a preselected mass to accumulate an appropriate amount of heat and then bringing the soldering iron into contact with the soldering area. Further reasonable temperature control can be achieved by combining the pre-stored heat with the energy supplied during contact. The soldering iron preferably provides the pressure to be maintained in the wire pad area and maintains the wire in contact until the solder hardens. In this manner the risk of wire movement during solidification of the solder is minimized. In cases where the required amount of heat is pre-stored in the soldering iron, the contact time of the soldering iron is selected to achieve the necessary heat transfer and to include a reasonable cooling period. If energy is supplied during contact, the contact period after the end of the energization period is controlled, thereby providing a reasonable cooling period. The soldering iron is preferably designed in such a way that after a reasonable amount of heat has been applied to the soldering part, the soldering iron remains in contact and dissipates the heat from the soldering part. This is accomplished, for example, by contacting thermally conductive support arms 36 and 37 (FIG. 3) in heat transfer relationship with the soldering iron's effective mass 32. In certain cases, multiple energizations may be advantageous. For example, a method is used in which a first energizing pulse is supplied to evaporate the insulator, and then a separate second pulse is supplied for soldering. A suitable two-pulse program sequence may include a first pulse of 6 volts lasting 8 msec to evaporate the insulation and a second pulse of 4 volts lasting 25 sec to effect the soldering. This mechanism establishes a relatively high temperature (above 371°C) to evaporate the insulation within a relatively short period of time, followed by a relatively low temperature for a relatively long period of time for soldering. Temperature (above 232°C) is established. As already mentioned with respect to FIG. 1, the control system for the soldering iron includes a power supply, a switching circuit and a timer control system. A particularly preferred system for single pulse soldering operations is shown schematically in FIG. As shown in the table, this device has a
Short duration high current pulses in the 400A range are required. For this purpose, any high current source can be used, but a storage battery 70 containing a 4-gate BC cell manufactured and sold by Gate Energy Products Inc. of Denver, Colorado, USA is a suitable low voltage, high current source. adopted as a source. Each cell is rated for 25 amp hours at 2V. A conventional charging circuit 72 is connected to the battery to maintain the amount of charge in all states. The switching circuit consists of six NPN power switching transistors 100 to 105 and three
Includes NPN drive transistors 92-94 and a start transistor 90, also of the NPN type. The timer controller includes a controllable monostable multivibrator 82 and an associated flip-flop circuit 80. Switch 78 is shown in the figures as initiating the energization cycle. In an actual system, switch 78 consists of a relay contact in a control computer system. switch 78
The normally closed contact is connected to the reset input R of the flip-flop circuit 80, and the normally open contact is connected to the set input S. One of the outputs of flip-flop circuit 80 is connected to a trigger input of monostable flip-flop circuit 82. A variable resistor 83 and a capacitor 84 are connected between the +120V power supply and the monostable circuit to provide time control. This variable resistor and capacitor is 5-500m
has been selected to provide a time period of seconds. Each time switch 78 moves from the position shown in FIG. 7 to the other position, flip-flop circuit 80
changes its state and generates a transient change at the output terminal. Monostable circuit 82 responds to a transient change and generates a positive pulse at its output terminal with a time width determined by the setting of variable resistor 83. The output of the monostable circuit is connected to the base of transistor 90. The collector of transistor 90 is connected to the +12V power supply via resistor 89, and the emitter is connected to ground potential. A bias resistor 88 is connected between the base of transistor 90 and the +12V power supply. The collector of transistor 90 is directly connected to the base terminals of drive transistors 92 to 94, and resistor 91
connected to ground potential via. transistor 9
The collectors of 2 to 94 are variable resistors 96 to 94, respectively.
98 to the positive terminal of battery 70. The emitter of transistor 92 is connected to the base terminals of power transistors 100 and 101, the emitter of transistor 93 is connected to the base terminals of power transistors 102 and 103, and the emitter of transistor 94 is connected to the base terminals of power transistors 104 and 105. be done. The positive terminal of the battery 70 is the soldering iron 3
0, and the other arm 37 of the soldering iron is connected to the transistors 100 to 10.
It is connected to the collector common connection line of No. 5. The emitters of transistors 100-105 are connected to the negative terminal of battery 70 via fuses 110-115, respectively. Variable resistors 96-98 balance the drive transistor and power transistor circuits so that they share the load appropriately. A positive pulse at the output of monostable circuit 82 causes transistor 90 to conduct, which causes drive transistors 92-94 to conduct, which in turn causes power transistors 100-105 to conduct. When a power transistor becomes conductive, a current flows from the positive terminal of battery 70 through soldering iron 30 and the parallel collector-emitter circuit of power transistors 100-105 and back to the negative terminal of that battery. In this way, the switch 78 is activated, and the soldering iron 3
0, a large current pulse having a time width according to the setting of the variable resistor 83 flows. This current flowing through the soldering iron depends on its size and composition. The two cells in the battery 70 apply a voltage somewhat higher than 4 volts to a tool of the dimensions shown in the table and pass current pulses of magnitude 150 to 250 amps. According to the three cells, the voltage is
The value is somewhat higher than 6V, and the current pulse is 250~
The value is 325A. Also, according to the four cells, the voltage is somewhat higher than 8V, and the current pulse is 275V.
The size will be ~425A. As already mentioned, in some cases e.g.
A multiple pulse sequence is employed that generates a pulse at 6V for 8 msec to produce the insulator evaporation temperature, followed by a pulse at 4V for 25 msec to perform soldering. A suitable circuit for such a pulse sequence is shown in FIG. In this case, the energy for soldering is provided by a three-cell battery consisting of a pair of cells 121 and another cell 120 connected in series. A charging circuit 122 is connected thereto to maintain a sufficient charge state. Two power transistors 18 connected in parallel
0 and 181 are used to connect a 4V power supply to the soldering iron 30, and transistors 170-172 form a drive circuit therefor. Three power transistors 160 to 162 connected in parallel are
A 6V power supply is used to connect the soldering iron, and transistors 150-152 form the associated drive circuit. Monostable flip-flop 13
0 forms timer A to control the 6V energization period, and the monostable multivibrator 140 is 4V
A timer B is formed to control the energization period. Monostable circuits 130 and 140 each have variable resistors 131 and 14 connected between them and a 12V power supply.
1. Variable resistor and related capacitor 13
2 and 142 form the timing circuit for the monostable multivibrator. The input terminal is connected to a trigger input of circuit 130 and the output terminal of circuit 130 is connected to a trigger input of circuit 140. If resistors 131 and 141 are set to 8 ms and 25 ms, respectively, then when a transient trigger signal is applied to terminal 135, a positive 8 ms pulse will occur at the output of circuit 130, followed by a positive 8 ms pulse. 25 m positive to the output of circuit 140
Second pulse occurs. The output of circuit 130 is NPN via resistor 153.
Connected to the base of transistor 150. The collector of the transistor 150 is connected to a +12V power supply via a resistor 154, and is also directly connected to the base of an NPN transistor 151. The collector of transistor 151 is connected to series resistors 155 and 156.
are connected to the +12V power supply through the resistors, and the nodes of these resistors are connected to the base of the NPN transistor 152. The emitters of transistors 150 and 151 are connected to ground potential;
Emitter 2 is connected to +12V power supply. The collector of transistor 152 is connected to the base terminals of NPN power transistors 160-162.
The positive terminal of the battery 120 is the parallel transistor 1
60 to 162, and their emitters are connected to fuses 163 to 16, respectively.
5 and a soldering iron 30 to the negative battery terminal. The output of circuit 140 is connected to ground potential through resistors 173 and 174, and the node of these resistors is
Connected to the base of NPN transistor 170.
The emitter of transistor 170 is connected to the base of NPN transistor 171, and the emitter of transistor 171 is connected to ground potential. The collectors of transistors 170 and 171 are connected to the +12V power supply through series resistors 175 and 176, and the node of those resistors is connected to PNP transistor 1.
72. The emitter of transistor 172 is connected to the +12V power supply, and its collector is
Connected to the base terminals of NPN power transistors 180 and 181. The positive terminal of battery 121 is connected to a common collector circuit of parallel transistors 180 and 181 whose emitters are connected to fuses 182 and 183, respectively.
It is also connected to a negative battery terminal via a soldering iron 30. The trigger pulse at terminal 135 energizes monostable circuit 130 to generate an output pulse, thereby causing transistors 150 to 150 in the drive circuit to
152 is made conductive. The conduction of these transistors also connects parallel power transistors 160-162.
conduction. As a result, a large current pulse with a time width determined by the setting of the variable resistor 131 is supplied from the 6V battery power supplies 120 and 121 to the soldering iron. Termination of the pulse at the output of circuit 130 triggers operation of monostable circuit 140 to generate an output pulse that causes drive transistors 170-172 to conduct.
The conduction of these transistors also causes parallel power transistors 180 and 181 to conduct. As a result, from the 4V power supply 121, the transistor 180
A large current pulse is supplied to the soldering iron via 181 and 181. The time width of this pulse is determined by the variable resistor 14.
This is given by the setting of 1.

[Brief explanation of drawings]

1 is a partial plan and block diagram illustrating a system constructed in accordance with the present invention; FIG. 2 is a partial cutaway view showing details of the wire placement and soldering iron on the circuit board of said system; and FIG. The figure is a perspective view showing the wire, soldering iron and terminal pad,
4 and 5 are diagrams illustrating soldering performed according to the present invention; FIG. 6 is a diagram illustrating the temperature distribution during the soldering operation; and FIG. 7 is a diagram illustrating the temperature distribution during the soldering operation. FIG. 8 is a circuit diagram showing a single-pulse control system for energizing a soldering iron. FIG. 8 is a circuit diagram showing a multi-pulse control system for energizing a soldering iron. 5... Circuit board, 6... Adhesive surface layer, 10... Wire guide, 11... Insulated copper wire, 20... Wire drawing iron, 30... Soldering iron, 32... Trowel tip (chip), 40 ...X-Y feeder, 42...
...computer control device, 44...position detector,
46...Timer control device, 48...Solenoid or pneumatic actuator, 49...Control circuit, 50...Switching circuit, 52...Power source.

Claims (1)

[Scope of Claims] 1. A method for soldering a wire to a terminal pad or the like on a circuit board using a soldering iron of a predetermined mass in the presence of solder having a melting point of approximately 232°C (450°C). (a) the amount of thermal energy that can be stored by the effective mass of the soldering iron is slightly greater than the amount of thermal energy required for effective soldering with solder having a melting point of 232°C; (b) heating a soldering iron having said effective mass to a predetermined high temperature that is not so high that the soldering iron rapidly deteriorates; (c) bringing the soldering iron into thermally conductive contact with a wire to be soldered placed on the pad; and (d) during that contact: (i) bringing the wire and the terminal pad into contact with each other; (ii) solidifying said solder; and (e) substantially directly applying said selected amount of thermal energy to complete the soldering. (f) the heating temperature of the soldering iron is such that no substantial heat transfer occurs from the terminal pad to the circuit board;
A method for rapidly soldering wire onto a terminal pad, characterized in that the temperature is such that sufficient heat transfer to the soldering area is achieved in less than 500 msec. 2. The method of claim 1, wherein the total contact time of the soldering iron is less than 50 msec. 3. The method of claim 1, wherein the soldering iron is heated to a temperature higher than 538°C (1000°C). 4 The temperature of the soldering iron is 872-1093℃ (1600-2000〓)
4. The method according to claim 3, wherein the method is heated to . 5. A method as claimed in claim 1, characterized in that the soldering iron is heated to the selected high temperature before contacting the wire to be soldered. 6. A method as claimed in claim 1, characterized in that after the soldering iron comes into contact with the wire to be soldered, it is heated to the preselected high temperature. 7. The method of claim 1, wherein the terminal pad is coated with solder before coming into contact with the soldering iron. 8. The method of claim 7, wherein the terminal pad is coated with a non-eutectic solder. 9. The method of claim 1, wherein the terminal pad is pre-tinned. 10. The method of claim 1, wherein the wire is coated with solder before contacting the soldering iron. 11. The method of claim 1, wherein the solder used to form the solder joint has a predetermined configuration. 12. The method of claim 1, wherein the solder used to form the solder joint comprises a fluid. 13. A method for soldering an insulated wire to a terminal pad coated with solder having a melting point of approximately 232°C (450°C) on a circuit board using a soldering iron having a predetermined effective mass, comprising: (a) the above-mentioned method; When the effective mass of a soldering iron is heated to a preselected high temperature, the amount of thermal energy stored in the mass evaporates the insulation of the wire and allows effective soldering with solder having a melting point of approximately 232°C. (b) placing a soldering iron of said selected mass at a predetermined height that is not so high that the soldering iron rapidly deteriorates; (c) contacting said soldering iron with an insulated wire placed on said solder-coated terminal pad; consuming said amount of thermal energy to substantially (i) evaporate insulation on the wire in the area of said contact point, and (ii) then evaporate insulation on a side of the wire opposite said contact point; (iii) melting the solder on the solder coated terminal pad; and (e) transferring substantial heat from the terminal pad to the circuit board or other element by the substantial consumption of the amount of thermal energy. (f) A method for rapidly soldering insulated wire to terminal pads, characterized in that no movement occurs; and (f) the total contact time for said soldering is less than 500 msec. 14. The method according to claim 13, wherein contact between the soldering iron and the wire is maintained until the solder solidifies. 15. A method according to claim 14, characterized in that the total contact time of the soldering iron is less than 50 msec. 16 (a) the preselected high temperature is 872 to 1093;
(b) The effective mass of the soldering iron is approximately 82×10 ^-6 cm ³ (5×
14. The method according to claim 13, wherein the method is comprised of a mass of about 10 ^-6 in ³ ). The method according to claim 13, characterized in that the soldering iron is heated to the predetermined high temperature by passing a current of 50 to 500 A for 175 to 100 m seconds. 18. The method of claim 13, further comprising heating the soldering iron before contacting the insulated wire. 19. The method according to claim 13, wherein the soldering iron is heated after being brought into contact with an insulated wire. 20 The soldering iron weighs 100 to 800 g of the wire.
14. The method of claim 13, wherein the contact pressure is applied to the terminal pad at a contact pressure of . 21. A method for soldering an insulated wire onto a solder-coated terminal pad of a circuit board with a solder having a melting point of about 232°C (450°C) using a heated soldering iron, the method comprising: (a) said soldering iron; When the effective mass of the wire is heated, the thermal energy to be supplied from the soldering iron during soldering causes the insulation of the wire to evaporate and scatter, and the melting point is approximately 232°C.
(b) selecting the effective mass to be sufficient to melt the solder of the solder for effective soldering; (c) selecting the heating period and temperature at which said soldering iron is heated such that (i) the temperature transferred to the insulation in the contact area exceeds its evaporation temperature; ii) ensuring that the temperature of the solder on the pre-solder-coated terminal pads exceeds said melting point of approximately 232°C for the minimum amount of time necessary for effective soldering, and (iii) the temperature of the circuit board adjacent to the terminal pads; A method for high-speed soldering of insulated wire to terminal pads, characterized in that the temperature does not exceed a temperature that would cause deterioration of the circuit board. 22 Achieve a rapid temperature rise after contact by heating the soldering iron to a temperature that does not cause rapid deterioration of the soldering iron and reach the circuit board beyond the terminal pad during contact to form the solder joint. 22. A method according to claim 21, characterized in that heat transfer is minimized. 23 Soldering iron 872~1093℃ (1600~2000〓)
22. A method according to claim 21, characterized in that the method is heated to . 24 The effective mass is approximately 82×10 ^-6 cm ³ (5×
22. The method according to claim 21, characterized in that the amount of water is about 10 ^-6 in ³ ). 25 The temperature distribution achieved by heating the soldering iron is such that (a) the temperature of the soldering iron is higher than 538°C (1000°C), and (b) the evaporation and scattering of the wire insulation reaches 399°C (750°C).
〓) Increase the temperature of the board near the terminal pads to 288°C (550°C).
22. The method according to claim 21, characterized in that: 〓). 26 The soldering iron has a relatively small effective mass that is thermally coupled to a relatively large mass, and this effective mass is used to store heat for soldering.
22. The method of claim 21, further comprising dissipating heat within the relatively large mass to cool the solder after soldering. 27 A system operative in the presence of solder for soldering wires to terminal pads on a circuit board, comprising: (a) a soldering iron having a predetermined effective mass; and (b) thermal energy applied to said soldering iron. means for adding (i) the temperature of said soldering iron to a predetermined high temperature that does not rapidly deteriorate the soldering iron, and (ii) the amount necessary for effective soldering to said soldering iron. (c) said means for supplying thermal energy for storing an amount of thermal energy which is slightly larger than the soldering iron and which is substantially used up during the formation of the solder joint; means for contacting the wire to be soldered, the means being capable of (i) transferring sufficient heat through said contact to complete the soldering, and (ii) allowing solidification of the solder; (d) soldering a wire to a terminal pad, wherein the effective mass and the thermal energy supplied thereto are selected to achieve soldering in less than 500 msec. system for attaching. 28. The system of claim 27, wherein the effective mass and the value of the thermal energy applied to the mass are selected to allow soldering to occur in less than 50 milliseconds. 29. The system of claim 27, wherein said means for supplying thermal energy to said soldering iron is capable of raising the temperature to greater than 1000°C. 30. The system of claim 27, wherein said means for supplying thermal energy to said soldering iron is adapted to raise the temperature to 872-1093°C (1600-2000°). 31 means for said system further coupled to said means for supplying said thermal energy, said system further comprising: relative movement of said soldering iron and said circuit board after storing said predetermined amount of thermal energy in said soldering iron; 28. The system of claim 27, further comprising means for bringing the soldering iron into thermally transferable contact with the wire and the terminal pad by providing a. 32. Means coupled to the means for providing the thermal energy, the system further comprising: relative movement of the soldering iron and the circuit board before accumulating the predetermined amount of thermal energy in the soldering iron; 28. The system of claim 27, further comprising means for bringing the soldering iron into thermally transferable contact with the wire and the terminal pad by providing a. 33. The system of claim 32, wherein the soldering iron includes a tip for dissipating thermal energy after soldering, and a heat container heat transferably coupled to the tip. . 34. Claim 27, characterized in that the means for supplying thermal energy to the soldering iron supplies a plurality of pulses of energy.
System described in section. 35. The pulse comprises a short, relatively high energy pulse sufficient to evaporate insulation from the wire, followed by a relatively long, relatively low energy pulse for soldering. A system according to claim 27.