JPH0475776A - Solder dipping device - Google Patents

Abstract

PURPOSE:To eliminate the fluctuation in the thermal stresses to the pats to be dipped in solder and to uniformize quality by installing guide jigs for positioning and holding the parts to be dipped in solder relative to the surface of molten solder in the vicinity of the front surface of a solder dipping tank. CONSTITUTION:The molten solder 5 is kept flow over from the solder dipping tank 12 and a printed circuit board 6 is installed in this state to a stay 16a of the holder 16 in such a manner that the solder dipping surface is opposed to the surface 5a of the molten solder. Two pieces of the guide jigs are thereafter fitted to the prescribed position of the solder dipping tank 12 corresponding to the margin region exclusive of the required solder dipping area of the printed circuit board 6 in at least the position where the stay 16a is evaded in such a manner that the step is positioned on the molten solder side. The holder 16 is then sufficiently lowered by operating a gear mechanism 8 of a control section 10. Only the printed circuit board 6 is thereby held to the guide jigs 15 but the required soldering area is not concealed by the guide jigs 15 and, therefore, the entire required area is dipped in solder.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a solder dipping device used for soldering printed circuit boards and preliminary soldering to external connection terminals of electronic devices such as semiconductor devices, and is used to melt solder on products to be dipped. By equalizing the immersion depth in the liquid, the height of the molten solder surface is constant, with the aim of reducing variations in thermal stress on the soldered dipped products and improving productivity by uniformizing quality. a holder for supporting and holding a product to be dipped in solder with its lower surface facing the molten solder surface of the solder dipping tank; and a holder at a position corresponding to the solder dipping tank. A solder dipping device comprising at least a control unit having a means for pushing the solder dipping device under the soldering device, wherein the solder dipping tank is configured to dip the solder in a blank area other than the required solder dipping area of the solder dipped product as described in 2. A guide jig is provided to hold the product at a predetermined position relative to the molten solder surface.

[Industrial application field]

The present invention relates to the process of soldering printed circuit boards and the process of preliminary soldering to external connection terminals of electronic devices such as semiconductor devices. The present invention relates to a solder dipping device that improves productivity by eliminating variations in thermal stress on dipped products and making quality uniform.

With the recent increase in reliability of electronic devices such as semiconductor devices,
In soldering, variations in the thermal stress on the electronic device during the soldering process and solder dipping have become less likely to affect its characteristics, and there is a strong demand to reduce this.

The variation in thermal stress in this case is influenced by multiple factors such as molten solder temperature, solder immersion time, solder immersion area (volume), etc. Among these, the solder immersion area (volume) is determined by uniformity of solder immersion depth. Since this cannot be done satisfactorily, a solution is desired.

[Prior Art] FIG. 2 is a diagram showing an example of the configuration of a conventional solder dipping device.

The figure shows a case where a printed circuit board on which a plurality of electronic devices such as semiconductor devices are mounted is used as a day-knob product to be soldered.

In FIG. 2, which is shown in a partially sectional side view, an overflow type solder dipping tank 1, which has a size that can at least cover the required products to be dipped in solder, is connected to a solder dipping tank 2 in the center and the solder dipping tank 2 in the center. A solder supply tank 3 having a higher height than the solder dipping tank 2 surrounds the dipping tank 2 with a certain distance and communicates with the solder dipping tank 2 near the bottom thereof, and a solder supply tank 3 has a height higher than that of the solder dipping tank 2, and the solder molten liquid after the work is carried out. It is composed of a receiving tray 4 for discharging.

In this case, the molten solder 5 supplied to the solder supply tank 3 so as to exceed at least the height of the solder immersion tank 2 overflows from the surrounding wall surface of the post-read solder immersion tank 2 that fills the solder immersion tank 2 and is supplied with solder. Tank 32-.

The recess between the two is depressed, and the communication part 3 is not shown by the broken line of the recess.
From a, it accumulates in the prisoner 4 and is discharged to the outside.

Therefore, in the solder dipping tank 1, the surface 5a of the molten solder 5 in the solder dipping tank 2 is always at the same level, and the scale that oxidizes when exposed to the atmosphere is immediately discharged together with the overflowing molten solder, so that the surface 5a of the molten solder 5 in the solder dipping tank 2 is at the same level. A clean liquid surface always appears.

On the other hand, a printed circuit board 6 as a product to be dipped in solder, on which a plurality of electronic devices 6a such as semiconductor devices are mounted with external connection terminals 6b'l exposed, has a surface to be dipped with solder in the solder dipping tank 2 described in 1. It is held and fixed to a holder 7 so as to correspond to and face the molten solder surface 5a, and furthermore, the holder 7 has a flange 7a provided on the other end side (the upper side in the figure), which is horizontally leveled by a gear mechanism 8, for example. 6. While holding the soil, the end of arm 9 moves downward. Two removable parts are installed.

Note that 10 is a control section that controls the operation of the gear mechanism 8.

Then, with the molten solder 5 overflowing from the solder dipping tank 2 described above, the gear mechanism 8 of the control unit 10 is operated to lower the printed circuit board 6 by a preset amount, and the solder on the printed circuit board 6 is lowered by a preset amount. Electronic device equipped with dip surface 6
By immersing the external connection terminal 6h in the molten solder surface of the printed circuit board 6, a solder dipping operation can be performed on the printed circuit board 6.

Furthermore, in order to pre-solder only the external connection terminals of a single electronic device such as a semiconductor device, a plurality of electronic devices 6a are connected to the external connection terminals 61) on the above-mentioned printed circuit board 6 as shown in (21). Preliminary soldering to the required depth can be achieved by replacing the exposed plate-shaped jig 6° with the jig II and adjusting the lowering amount of the jig II using the gear mechanism 81 of the control unit 10. can work efficiently.

However, it is difficult to repeatedly replace the printed circuit board 6 and the jig 6'' in exactly the same way every time, and it is easy to cause relative positional deviation or inclination with respect to the melting half-day surfaces C1 and C1 and C2.

Therefore, the solder dipping operation is not necessarily carried out under the same conditions every time, making it difficult to achieve a uniform operation, which has the disadvantage of inducing variations in the characteristics of the soldered dipped products due to variations in thermal stress.

Furthermore, recently, the pudding +-i board 6 has become larger, and -
Preliminary solder (external connection terminals of electronic devices)
If a large jig 6 is used for the dipping operation, the immersion area with respect to the molten solder surface 5a will inevitably become large, but especially in such a case, no matter how precisely the amount of descent by the gear a mechanism 8 is set, Molten solder surface 5a of each of the solder dipped products mentioned above
There is a drawback that the entire surface cannot be immersed uniformly in the molten solder due to the slight inclination to the surface.

[Problems to be Solved by the Invention] With conventional solder dipping equipment, when the solder dipped product becomes large, it is not possible to constantly immerse the solder dipped product in molten solder under the same conditions, which causes variations in thermal stress. There was a problem in that due to this, variations in characteristics were likely to occur, and no improvement in productivity could be expected.

[Means to solve the problem]

- The problem described in J2 is that the solder dipping tank has a constant height of the molten solder surface, and the solder dipping surface faces the molten solder surface of the solder dipping tank. a holder for holding the holder at a position corresponding to the solder dipping tank; and a control section having means for moving the holder downward at a position corresponding to the solder dipping tank, the solder dipping apparatus comprising: This problem is solved by a solder dipping device that includes a guide jig that holds the solder dipped product at a predetermined position relative to the molten solder surface in a blank area other than the required solder dipping area of the solder dipped product.

[For production]

If the product to be soldered and dipped can be immersed in the molten solder liquid evenly and under the same conditions, the solder dipping operation can always be performed under the same conditions.

In the present invention, a guide jig for positioning and holding the product to be dipped in solder with respect to the surface of the molten solder is mounted near the top surface of the solder dipping tank, and the guide jig is set for the time of dipping the product to be soldered. There is.

Therefore, solder dipping work can be performed under the same conditions at all times, which eliminates variations in the thermal stress from molten solder on the products to be dipped, and improves productivity without causing variations in characteristics. can.

〔Example〕

FIG. 1 is a diagram illustrating a configuration example of a solder dipping device according to the present invention, in which (A) is an overall configuration diagram, and (B) is a state during solder dipping viewed from the direction of arrow A in (A). FIG.

In the figure, the product to be dipped in solder is the same pudding as in Figure 2.
-5 board.

In FIG. 1(A), the solder dipping tank Wi 11, which has a size that can at least cover the required product to be soldered dipped, that is, the printed circuit board 6, has a solder dipping tank 12 in the center and a portion of the solder dipping tank 12 that is slightly larger than the solder dipping tank 12. A solder supply tank 13 having the same height as the solder dipping tank 12, which surrounds the solder dipping tank 12 while maintaining a positive atmosphere and communicates with the solder dipping tank 12 near its bottom surface, and a solder supply tank 13 for discharging the solder melt after work. In particular, in the solder dipping tank 12 in this case, which is composed of a saucer 14, there are 31 windows 12a passing through the peripheral wall at a plurality of locations at the same height near the upper side of the peripheral wall.
is formed.

Therefore, since the molten solder 5 supplied from the solder supply tank 13 to the solder dipping tank 12 overflows at the window 12a of the solder dipping tank 12, the liquid level is always the same as in the case of FIG. At the same time, the surface 5a of the molten solder 5 in the solder dipping tank 12 has a clean liquid surface free from scales.

Furthermore, two rectangular guide jigs 15 are fitted near both ends of the solder immersion tank 12 between the opposing walls.
For example, a step d with the molten solder side concave is formed between both end portions and a portion excluding the both end portions, and the solder dipping tank 1
The fitting position to 2 can be changed freely.

On the other hand, reference numeral 16 in the figure is a holder for holding the product to be dipped in solder.In particular, the holder 16 in this case receives the printed circuit board 1 and board 6 explained in FIG. Two stays 16a are attached to hold the stay 16a, and a flange 16b is provided at the upper end, and as explained in FIG.
It is mounted on the end of an arm 9 which moves downward while remaining horizontal by a gear mechanism 8 built into the shaft.

Therefore, first, with the molten solder 5 overflowing from the solder dipping tank 12 described above, the stay 16a of the holder 1G is
solder dip surface of the M plate 6 is the molten solder surface 5a
After placing it so that it faces the
6a and the solder day of the printed circuit board 6.
The two guide jigs 15 are fitted into predetermined positions of the solder dipping tank 12 corresponding to the blank area excluding the required area of the knob so that the stepped portion faces the molten solder side, and the gear mechanism 8 of the control unit 10 is operated. When the holder 16 is lowered sufficiently, as shown in (B), only the printed i-board 6 moves to the above-mentioned guide jig 15.
However, the required area for soldering is limited to the guide jig 1.
Since it is not hidden by 5, the entire required area can be dipped with solder.

Particularly in this case, the position where the guide swamp 15 contacts the molten solder surface of the board 6 is determined by the height difference d of the guide swamp 15, so the height difference d must be set in accordance with the board 6. Therefore, the solder dipping operation can be performed reliably with a constant amount of solder immersion without causing the substrate 6 to tilt with respect to the liquid level or causing variations in the amount of solder immersion.

Incidentally, when the holder 1G is raised, the stay 16a of the holder 16 supports the printed circuit board 6 from below and lifts it up, so that the printed circuit board 6 can be separated from the solder dipping bath 12.

In addition, as shown in (1-1) of the printed circuit board 6,
In addition to replacing the plate-shaped jig 6° described in FIG. By setting the step amount d@according to the solder dip depth do of the electronic device mounted on the jig 6'', it is possible to prevent the jig 61 from tilting with respect to the liquid level or causing variations in the amount of solder immersion. It is possible to carry out reliable preliminary soldering with a constant amount of solder immersion.

Furthermore, at (1-2), external connection terminal 6b to be pre-soldered
In the case of an electronic device 6c which is a flange 1 type in which the flange 1 protrudes from both sides, the above-mentioned stays 16 are placed at positions corresponding to both sides near both ends in the length direction, as shown in (i).
A groove 17a for positioning the guide jig 15 and a groove 17b for positioning the guide jig 15 are formed. l Electronic device holding plate 1
8 is attached, and with the electronic device holding plate 18 open, move the electronic device 6c in the direction of the arrow so that the direction of the external connection terminal 6b is in the thickness direction of the jig 17.・Insert sea urchin! , 1. When the electronic device holding plate 18 is closed and the electronic device 6G is clamped and fixed, the jig I
By setting the thickness of 7 in accordance with the electronic device 6c, only the external connection terminal 6b of the electronic device 6c can exert the thickness force n6 of the jig 17, as shown in (ii).

Therefore, in the groove 17a portion of the jig 17, the stay 16a
By lowering the jig 17 in the same manner as described above, it is possible to carry out reliable preliminary soldering with a constant amount of solder immersion.

Particularly in this case, there is an advantage that after soldering the external connection terminals on one side, the vagina jig 17 can be turned over and the external connection terminals on the other side can be soldered under exactly the same conditions.

19 in the figure is a jig 17 for holding the electronic device holding plate 18.
It is a screw that is screwed into and fixed in place.

As explained above, with the solder dipping device having such a configuration, the solder dipping operation can be performed under the same and uniform conditions every time, so there is no variation in thermal stress on the soldered product, and therefore the characteristics It is possible to stably perform solder ejection work continuously.

In addition, in the case of the solder dipping tank 2 explained in FIG. 2 where the molten solder overflows on the upper side, the guide jig 15 mentioned above
Exactly the same operation can be performed by placing the solder dipping tank 2 on the upper side of the solder dipping tank 2 so as to extend vertically in the same direction, that is, to protrude upward.

(Effects of the Invention) As described above, according to the present invention, the immersion depth of the solder-dipped product in the solder melt can be easily made constant, thereby eliminating variations in thermal stress on the solder-dipping product and making the quality uniform. A solder dipping device designed to improve productivity can be provided.

In the description of the present invention, two separate guide jigs are used, but the two guide jigs are connected at both ends. The same effect can be obtained by using a guide jig that has a "mouth-shaped" shape when viewed from above.

FIG. 2 is a conceptual diagram showing an example of the configuration of a conventional solder dipping device.

In the figure, 5 is molten solder, 5a is the surface, 6 is a printed circuit board, 6", 17 is a jig, 6a, 6c
, is an electronic device, 6b is an external connection terminal, 8 is a gear mechanism, 9 is an arm, 10 is a control unit, 11 is a solder dipping tank, 12 is a solder dipping tank, 13 is a solder supply tank,
14 is a saucer, 15 is a guide jig, 16 is a holder, 16a is a stay, 16b is a flange, 1
7a and 17b are grooves, 18 is an electronic device holding plate,
19 represents a screw, respectively.

[Brief explanation of the drawing]

Figure 1 shows the configuration of the solder dipping device according to the present invention (ii). Mr. Seki's solder 5''f chestnut arm is the worst example of Noro.

Claims (3)

[Claims] (1) Solder dipping tank with a constant height of molten solder surface (1
1) and the solder dipping surface side to the solder dipping tank (11).
), and the holder (16) is moved up and down at a position corresponding to the solder dipping tank (11). A solder dipping device comprising at least a control section (10) having means, wherein the solder dipping tank (11) is configured to hold the solder dipped product in a blank area other than a required solder dipping area of the solder dipped product. A solder dipping device comprising a guide jig (15) that holds the solder in a predetermined position relative to the molten solder surface. (2) The solder dipped product is a printed circuit board (6) on which a required electronic device (6a) is soldered in a predetermined position.
The solder dipping device according to claim 1, characterized in that: (3) The solder dipped product described above is connected to the external connection terminal (6b
) Electronic devices to be pre-soldered to parts (6a, 6c)
2. The solder dipping device according to claim 1, further comprising a jig (6', 17) on which the external connection terminal (6b) is mounted such that the external connection terminal (6b) protrudes.