JPH02147162A - Soldering method in automatic soldering apparatus - Google Patents

Abstract

PURPOSE:To make solder sticking quantity and heating thermal quantity uniform at each joining position by reducing solder supplying quantity of tip and heating time in order to execute the joining and cleaning the tip with air flow at each time of completion of joining to each work. CONSTITUTION:While shifting the trowel tip 5 at joining positions 15a, 15b, 15c in order, the soldering is executed. Feeding lengths of the solder wire 6 are made to about 3mm at the time of joining the joining position 15a in the starting side of the joining and about 1.5mm at the joining position 15b and about 0.5mm at the joining position 15c in the completing side. The heating time with the tip 5 is reduced to about 1.2sec, 0.8sec and 0.5sec, respectively. At the time of completion of the joining at first time, the compressed air is injected from the air blowing pipe 8, and the solder slag and the remaining solder liquid stuck to the tip 5 are removed to execute the cleaning. The solder sticking quantity and heating thermal quantity at each joining position can be uniformized and the finishing condition is uniformized.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a soldering method in an automatic soldering device, and in particular, the present invention relates to a soldering method in an automatic soldering device, and in particular, when a workpiece has a plurality of joint points, each joint point is sequentially connected with a single iron tip. Targets things that are joined.

(Prior art) For example, when a flexible printed wiring board (hereinafter simply referred to as a wiring board) has multiple bonding points, if the distance between adjacent bonding points is sufficiently large, multiple soldering tips can be used. All joints can be soldered at once. However, if the joint locations are close to each other, the joints will be sequentially performed using - number of iron tips.

Conventionally, when soldering is performed in sequence in this manner, the amount of solder supplied to the iron chip and the heating time of the joining location are kept constant.

(Problems to be Solved by the Invention) As mentioned above, if solder joints are performed at multiple locations in sequence under uniform conditions, the finished state of the joints will not be consistent, which will adversely affect the joint quality and electrical characteristics. was there. For example, as shown in FIG. 1, when bonding the wiring board W to the circuit board 13 at five bonding points 15g, 15b, and 15c, the thickness inside the solder increases as the bonding progresses. , the last joint 15c sometimes protrudes into a square shape.

In particular, in the case where a sheet-shaped wiring board W is directly joined to the circuit board 13, in which surface-to-surface joining is performed, the quality of the joining is markedly reduced, and moreover, the smaller the diameter value of the joining holes consecutively provided on the wiring board W, the lower the , this tendency was remarkable.

Usually, an automatic soldering device is equipped with an air blowing pipe for cleaning the soldering iron tip, and the airflow ejected from the pipe is used to remove solder scum and excess solder liquid.

Therefore, if you clean the tip with a saw after each joint,
The above-mentioned problems are eliminated and the bonding quality can be made uniform. However, in this case, not only the time required for cleaning is lost, but also the time required for the chip to return to temperature after being cooled by the jetted air flow is lost, and the efficiency of the soldering work is significantly reduced.

This invention has been proposed in view of the above, and it is possible to improve the working conditions during soldering, especially the amount of solder supplied and the heating time, so that soldering at multiple locations can be performed one after another. The purpose of the present invention is to provide a soldering method that can provide a high bonding quality and improve work efficiency.

(Means for Solving the Problems) In the present invention, a plurality of joint points are set on a fixed workpiece, and in an automatic soldering device that sequentially solders these joint points with one soldering tip, the joining starting side The solder supply amount to the soldering iron tip and the heating time by the soldering iron tip are decreased from the joining point to the joining point on the joining end side, and the joining is performed sequentially, and after each workpiece is successively joined, the air is A cleaning air stream was blown out from the blow-off pipe toward the trowel tip.

In the case where bonding is repeated twice in sequence, the amount of solder supplied during the next bonding is set to be reduced at each bonding location compared to the amount of solder supplied during the first bonding, and the amount of solder supplied and heating time during the next bonding are adjusted accordingly. It was decided that the bonding would be performed sequentially, decreasing from the bonding location on the bonding start side to the bonding location on the bonding end side.

(Function) 0 solder to the iron tip (By reducing the amount of solder supplied and performing the bonding in sequence, excess solder liquid is prevented from accumulating on the iron tip, and the soldering top position at each bonding point is uniform.) In addition, the temperature of the tip gradually increases within the allowable range as the welding process progresses, but by reducing the heating time of each welding point with the trowel tip, the heating of each welding point can be reduced. The amount of heat can be made uniform, and as a whole, the finished shape inside the solder can be made uniform, resulting in a constant bonding quality.

Each time each workpiece is welded in sequence, the iron tip is cleaned with the air flow emitted from the air blowing pipe.
Soldering can be performed using the iron tip that has been cleaned for each work, and since the iron tip can be cleaned using the time required to replace the work, it is possible to eliminate loss of working time.

(Example) 1 to 4 show embodiments of the invention.

In FIG. 1, the automatic soldering device includes a soldering machine unit 1 supported by operating means such as an industrial robot, and a workpiece W.
It is equipped with a workpiece holding means to hold and hold the workpiece in an appropriate welding posture. The soldering machine unit 1 is a commercially available ready-made product, which fixes a soldering tip 5 via a chuck 4 to the lower end of a slide arm 3 that is operated to move up and down, and inserts a soldering wire 6 toward the tip of the iron tip 5. A guide pipe 7 for feeding and guiding air, and an air blowing pipe 8 for cleaning are arranged. 9 is the above-mentioned both pipes 7.8
It is a holder that supports.

The workpiece holding means 2 is attached to a fixing member that supports the soldering machine unit 1 via a differential absorption mechanism (not shown), and holds the workpiece W in a proper bonding posture in advance of the soldering iron tip 5. Furthermore, even after the iron tip 5 is separated from the workpiece W after bonding, the workpiece W is held and held until the solder liquid solidifies. A pressing body 10 is provided at the lower end of the work holding means 2. The suppressor 10 is made of fluororesin to prevent damage to the workpiece W, and has an escape groove 11 formed at its tip end to span the soldering area.

The workpiece W is a sheet-like electrical component typified by a flexible printed wiring board, and is made by printing a wiring pattern on one side of a film made of polyimide, polyester, or the like that is resistant to soldering heat.

This work W is placed on the circuit board 13 and screws 14
It is fixed. Bonding points 15a and 15b are arranged in rows at five locations on the sheet surface of the workpiece W.

15c is placed. The automatic soldering device performs soldering while sequentially moving through these joining locations 15a, 15b, and 15c.

In FIGS. 2 and 3, each joint 15a.

The sheet surface of the work W corresponding to 15b and 15c has semicircular joining holes 16 arranged in series, and each joining hole 1
Solder lumps 17 are preliminarily attached to the upper surface portions of the circuit boards 13 corresponding to 6.

As shown in FIG. 2, the bonding holes 16 and the solder lumps 17 are arranged sideways so that they partially overlap in plan view, and the bonding holes 16 are arranged such that the curved surfaces of the adjacent holes are in the same direction. They are formed differently. In FIG. 2, symbol P indicates each joint 15a.

15b and 15c, B is the width of the chip 5, D is the maximum longitudinal length of the joining hole 16, P and B
The actual length of 211IIISD is 1 mm. Third
As shown in the figure, a wiring pattern 18 is formed on the side of the joining hole 16 facing the circuit board 13.

As already mentioned, the workpiece W is formed using a plastic film as a base material, and the base film itself is not fused and is not easily compatible with solder fluid.

Therefore, soldering is carried out in two parts, and at the first time the wiring pattern 18 is mainly soldered as shown in FIG. 4(a).
The solder mass 17 is bonded to the solder mass 17, and the solder is built up so that the bonding hole 16 is filled during the next bonding to form the solder interior 19 as shown in FIG. 4(b), and the electrical characteristics as a whole are Joining is performed to satisfy both mechanical strength and mechanical strength.

Furthermore, each joint 15a * 15b,
15 c in order, the amount of feed of the solder wire 6 to the iron tip 5 and the heating time with the iron tip 5 (
Here, the bonding is performed while decreasing the contact time of the chip 5. Specifically, as shown in the work condition table in Figure 6, when welding the welding point 15a (first point) on the welding start side,
The feeding length of the solder wire 6 is set to 3 lengths, and when joining the 4th joint point 15b after the second fish, the solder wire is lengthened to 1.
Feed in 5mm increments, and then move to joining point 15 on the joining end side.
When bonding c (5th point), solder wire 6 by 0.5+am
to be sent.

As the bonding operation progresses, the amount of remaining solder adhering to the surface of the chip 5 increases little by little, as shown in FIG. Taking this increase into account, if the supply amount of the solder wire 6 is gradually reduced as described above, the solder ffi adhering to the circuit board 13 and the workpiece W side can be removed from each bonding point 15a, 15b,
15c can be made uniform.

In parallel with the decrease in solder supply amount, the heating time by the iron tip 5 was increased by 1.2 seconds from the welding start side to the welding end side, and by 0.8 seconds from the second point to the fourth point. seconds, 0.
Reduced to 5 seconds. As the joining work progresses, the tip temperature of the iron tip 5 changes from M1 to M as shown in FIG.
This corresponds to the gradual increase as shown in No. 5, and is intended to equalize the amount of heating heat applied to each joint portion 15a, 15b, 15c.

When the first bonding is completed in the manner described above, compressed air is blown out from the air blowing pipe 8 to remove solder scum and residual solder liquid adhering to the iron tip 5, thereby cleaning the iron tip 5. By this cleaning, the temperature of the iron tip 5 will be lowered to the 5th level.
Although the temperature decreases as shown by the symbol C in the figure, since the decrease temperature is 10 to 15 DEG C., the chip 5 is not cooled beyond the lower limit of the set temperature.

At the next time of joining, the amount of solder supplied and the heating time are reduced in the same way as the first time joining, and each joint location 15a is bonded.

15b and 15c are sequentially joined, but in particular, the amount of solder supplied to each joint 15a, 15b, and
Reduce the feed rate at 15c by about 115-1/6.

The heating time is set to be the same as for the first bonding. In FIG. 5, N1 to N5 are each joint portion 15a, 15b,
The tip temperature of the iron tip 5 corresponding to 15c is shown. After the next joining is completed, insert the iron tip 5 into the air blowing pipe 5 again.
Cleaning is performed by the airflow of debris, and preparation is made for the next workpiece W to be supplied. In other words, the iron tip 5 is cleaned during the replacement work of the workpiece W, thereby avoiding time loss.

As described above, by performing soldering while reducing the solder supply amount and heating time, each joint location 15a, 15b+
Since the solder adhesion amount and the heating heat amount in 15c were made uniform, the finished shape of the solder interior 19 could be made uniform and the bonding quality could be improved.

(Modified example) In the above embodiment, the case where soldering is performed in two steps has been explained, but the present invention can also be applied to a case where soldering is completed with only one sequential joining. There is no limitation to the joining method. In addition, in the example, in order to simplify the control, the solder supply amount and heating time were set to be the same from the second fish to the fourth point, but this is not necessarily necessary, and the solder supply amount and heating time are the same. It can also be set to gradually decrease.

The workpiece W may have any number of joints as long as it has multiple joints, but the workpiece W is particularly difficult to join.
In this case, it is preferable to clean the iron tip 5 in the middle of sequential joining.

(Effects of the Invention) As explained above, the present invention reduces the amount of solder supplied and the heating time when sequentially joining a plurality of joint locations.
By making it possible to equalize the amount of solder adhesion and the amount of heating heat at each joint, it is possible to improve the electrical conductivity of each joint, the peeling resistance of the workpiece, and other joint performance, as well as improve the internal finish of the solder. By keeping the values constant, we were able to make the bonding quality uniform. In addition, each time each workpiece is welded in sequence, the iron tip is cleaned by the air flow blown out from the air blowing pipe, so the iron tip can be cleaned using the time required to replace the workpieces. ,
Eliminates work time loss and improves work efficiency. Furthermore, if you clean the iron tip after each welding, the temperature of the iron tip may drop below the set temperature, but as described above, each workpiece is welded one after the other. A cycle in which cleaning is performed after each cycle is advantageous in that it is possible to prevent the iron tip from being excessively cooled and bonding can be performed immediately after cleaning.

[Brief explanation of the drawing]

Figures 1 to 6 show embodiments of the present invention;
The figure is a front view of the main parts of the automatic soldering device, Figure 2 is an overall plan view of the joint, Figure 3 is a sectional view of the joint, Figure 4 (a),
4(b) is a cross-sectional view of the joint location showing the joining process, FIG. 4(a) shows the initial joining state, and FIG. 4(b) shows the initial joining state.
indicates the next joining state. FIG. 5 is a state curve diagram of the iron tip showing the iron tip temperature and residual solder LML during sequential bonding, and FIG. 6 is a table of working conditions during sequential bonding. 5... Solder tip, 6... Solder wire, 8... Air blowing pipe, 13-... Circuit board, 15a, 15b, 15
cm...Joining point, 18...Wiring pattern, 19...
- Wax interior, W...work. 2 others Figure 2

Claims (2)

[Claims] (1) A soldering method using an automatic soldering device in which a fixed workpiece has a plurality of joint points set up, and these joint points are sequentially soldered using a single soldering tip, starting from the joint point on the joining start side. The solder supply amount to the soldering iron tip and the heating time by the soldering iron tip are decreased in order to join the parts to be joined on the finishing side, and after each workpiece is successively joined, air is discharged from the air blowing pipe for cleaning. A soldering method in an automatic soldering device characterized by ejecting an air flow toward a soldering iron tip. (2) A soldering method in which sequential bonding is repeated twice,
Compared to the amount of solder supplied during the first bonding, the amount of solder supplied during the next bonding is set to be decreased at each bonding location, and the amount of solder supplied and heating time during the next bonding is increased from the bonding location on the bonding start side to the bonding end side. 2. The soldering method in an automatic soldering apparatus according to claim 1, wherein the soldering is performed sequentially in decreasing numbers toward the joining locations.