JP2895822B2 - Pumping type soldering apparatus and its soldering method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to spot soldering to a printed wiring board after electronic components are mounted, and more particularly, to a soldering liquid which is pumped up from a molten solder tank by a bucket and exposed from a solder exposure port to a target location. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump-up type soldering device that performs soldering by making contact with the device, and a soldering method thereof.

[0002]

2. Description of the Related Art Heretofore, as an automatic soldering device for a printed wiring board after mounting electronic components, there has been a pumping type soldering device or a so-called jet soldering type soldering device. For example, Japanese Utility Model Laid-Open No. 5-65472,
0753.

The pumping type soldering apparatus disclosed in Japanese Utility Model Laid-Open No. 5-65472 has previously sunk a bucket (solder tank) having an upper surface opening and a blow-out tube arranged at a position lower than the upper surface opening in a solder bath. At the time of soldering, the bucket is pulled up from the solder bath, the molten solder liquid is blown out from the blow-out tube, and the solder is brought into contact with the lower surface of the printed wiring board to perform the soldering.

[0004] The jet soldering type soldering apparatus of the above-mentioned Japanese Patent Application Laid-Open No. Hei 6-260753 has a jet screw disposed below the surface of a molten solder tank in the same tank, and a tube having an upper part and a lower part communicating with each other. The lower part was buried below the liquid level of the molten solder tank, and the upper part was composed of a jet nozzle located above the liquid level of the molten solder tank.

With this configuration, when the jet screw located below the liquid level in the molten solder tank rotates, the molten solder is pushed out from the lower part of the jet nozzle toward the upper part, and overflows from the opening at the upper end of the jet nozzle. The melted solder comes into contact with the printed wiring board located near the upper end of the jet nozzle and is soldered.

In general, it is of course important to remove solder oxide from molten solder in order to perform good soldering of a printed wiring board. The speed at which the solder contact surface is separated from the soldering location is important. For that purpose, the molten solder contact surface must be stable,
If the liquid level of the molten solder moves up and down excessively during the infiltration of the solder, the optimum soldering conditions cannot be obtained, which may result in poor soldering.

[0007]

However, in the above-mentioned conventional pumping type soldering apparatus, the solder liquid that is fixed only by being exposed from a plurality of target locations, a solder exposure port having an unspecified shape and area is evenly distributed. It was actually very difficult to make contact with the destination. If the contact area is large, along with the distortion of the printed circuit board, the level of the device, the accuracy and level of the bucket, etc., the gas generated from the contact surface will separate the target location from the solder surface, so sufficient contact time And the contact pressure cannot be obtained.

[0008] In a soldering apparatus of the so-called jet soldering type, the solder liquid surface is oxidized unless a large amount of solder is constantly flowed from the solder contact surface. In addition, there is a problem that it is difficult to control the solder temperature when it is away from the heating source. Further, delicate adjustments such as adjustment of the liquid level at the time of contact of the solder contact surface and the separation speed of the contact surface are required, and it has been extremely difficult to maintain this in a stable state for a long time. In addition, the general jet-type soldering apparatus still has a problem that a large number of solder oxides are generated due to increased contact with air in the process of jet circulation.

In consideration of such a problem, in the above-mentioned conventional example, various considerations have been made at the time of soldering contact. However, at the time of separation from the contact point, the bucket is merely moved downward. For this reason, so-called stringing may occur at the time of separation, and there is a problem that the thread comes into contact with another portion to cause a short circuit. The occurrence of the stringing is presumed to be related to the melting temperature of the solder, the descending speed, or the environmental temperature.

At present, there has been no means for effectively solving the problems and problems described above.

[0011]

Therefore, the present invention has been made in view of this situation, and based on a pumping type soldering apparatus, suppresses the generation of solder oxide, maintains the flatness of the molten solder liquid level, The purpose is to improve the soldering of the printed wiring board by properly adjusting the amount of solder swelling at the time of soldering, and to effectively prevent stringing after soldering and reduce soldering defects. And a new pumping-type soldering device and a method for soldering the same.

[0012]

In order to achieve the above object, a pumping type soldering apparatus according to the present invention is configured as follows.

[0013] A bucket having an upwardly open solder pumping port and a solder exposure port opened upward below the horizontal position of the pumping port is moved up and down between the inside and outside of the molten solder liquid stored in the solder tank. Solder liquid exposed from the exposure port,
In a pump-up type soldering apparatus that performs soldering by making contact with a predetermined portion of a printed wiring board that has been conveyed and moved, a float having a predetermined volume that is appropriately moved by a moving means between the inside and outside of a solder liquid in a bucket is arranged. It is characterized by the following.

Further, a vibration means for applying a vertical vibration to the float is attached. Further, an inflow port opened sideways is formed at an intermediate position between the horizontal position of the solder pumping port and the horizontal position of the solder exposure port, and the inflow port allows a solder liquid to flow only into the bucket. It is characterized by having.

In the formation of the solder exposure port, a desired position of the bucket base where only the solder pumping port is formed is provided.
A cylindrical base having a predetermined opening shape and at least an upper part opened is fixed, and an opening of the cylindrical base is made to be a solder exposure port by perforating communication between the bottom of the cylindrical base and the inside of the bucket base. Is also good.

Next, a bucket having an upwardly opened solder pumping port and a solder exposure port opened upward below the horizontal position of the pumping port is immersed in the molten solder liquid stored in the solder tank. , Move it up and out of the molten solder liquid,
In the pumping type soldering method in which the solder liquid exposed from the solder exposure port is brought into contact with a predetermined portion of the printed wiring board and then the bucket is moved down and separated to perform soldering, the soldering portion of the printed wiring board is After bringing the solder exposure port close to, the float is moved forward and backward into the solder liquid in the bucket, and by adjusting the amount of exposure of the solder liquid from the solder exposure port, contact separation of the solder liquid to a predetermined location is performed. It is characterized by doing so. Further, after the solder liquid comes into contact with the soldering part, the soldering part is separated from the soldering liquid while applying longitudinal vibration to the soldering liquid.

The addition of the longitudinal vibration to the solder liquid may be performed by vibrating the float, although another vibration applying means may be provided.

[0018]

According to the above construction, the present invention operates as follows. The height of the exposure amount from the solder exposure port can be quickly adjusted by entering or leaving the float in the solder liquid. When the exposure amount is increased, the solder liquid on the oxidized surface flows down, and the non-oxidized solder liquid comes into contact.

When the bucket descends and enters the solder liquid level, before the solder liquid suddenly flows into the bucket from the solder pumping port, the solder liquid quickly flows in from the valve mechanism and agitates the bucket more than necessary. It will flow into every corner.

According to the above method, when the solder liquid is separated and separated from the contact surface, the float is vibrated little by little, so that the longitudinal vibration is propagated to the solder liquid, the separation and separation are performed smoothly, and the stringing is performed. Does not occur.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an overall perspective view schematically showing the present embodiment, and FIGS. 2 to 5 are side sectional views showing the operation state of the present embodiment in a stepwise manner.

The pumping type soldering apparatus (hereinafter, abbreviated as “this apparatus”) 1 of the present embodiment mainly includes a solder tank 2,
It comprises a bucket 3 and a float 4. The solder tank 2 has a box shape having a volume that can be accommodated with a sufficient amount of room in which the bucket 3 can be accommodated with the open upper part substantially open, and a heater 20 for solder heating is disposed at the inner bottom. I have. The inside thereof is filled with a solder liquid 21 obtained by melting the solder to a predetermined height. In addition, a squeegee 5 for contacting and moving on the surface of the solder liquid 21 is disposed in the upper open portion. Since the configuration of the solder bath 2 is a general configuration existing in the related art, further detailed description will be omitted.

The bucket 3 has a substantially rectangular tank shape with a hollow inside, and has a solder pumping port 30 opened upward.
And a plurality of solder exposure ports 3 opened upward at a position lower than the horizontal position of the solder pumping port 30.
1, 31,... Each of the solder exposure ports 31 is in contact with a predetermined soldering portion of the printed wiring board 6, and is formed so that its height position is substantially horizontally aligned.

An inlet 32 having a valve mechanism is formed in a side surface of the solder pumping port 30. The inlet 32 is
A pivot hinge 32 is provided at the upper edge of the solder pumping port 30.
A rectangular plate-shaped flap 32f hung on the h and configured to swing freely is arranged, and the inflow port 32 is closed by the flap 32f. A slightly protruding stopper 33 is formed at the lower end of the opening of the inflow port 32, and the lower end of the flap 32f is brought into contact with the stopper 33 to prevent outward swinging. 3 constitutes a valve mechanism that flows only in the internal direction. The vertical distance A of the lower end of the opening of the inflow port 32 with respect to the bottom of the bucket is:
It is set to be larger than the vertical distance B of the opening edge of the solder exposure port 31 (A> B).

The bucket 3 is provided with a support arm 34 held by elevating means (not shown) in a direction opposite to the solder pumping port 30. With the support of the support arm 34, the inside and outside of the solder liquid 21 are kept in a horizontal state. It is configured to move up and down while maintaining

A float 4 having a predetermined volume is disposed above the solder pumping port 30. This float 4 is lifted and lowered separately from the lifting / lowering means (not shown) of the bucket 3. By means (not shown), the liquid enters the solder liquid 21 from the solder pumping port 30 as appropriate.

Further, a vibrating means (not shown) is attached to the support rod 40 of the float 4, and the support rod 40 is arranged in a vertical direction (up and down direction).
Vibration is given. Note that the mechanisms of the above two kinds of lifting / lowering means and the vibration means are not the gist of the present invention and use a conventional general mechanism, so that the description of the specific mechanism will be omitted.

A transport guide 7 for transporting a printed wiring board 6 to be soldered is provided near the upper limit of the bucket 3 in the upper part of the apparatus 1.

[0029]

Operation of the Embodiment With the above configuration, the embodiment operates as follows. First, in a state where the bucket 3 is immersed in the solder bath 2 filled with the heated and melted solder liquid 21, the squeegee 5 is moved in contact with the solder liquid 21 along the liquid surface to float on the liquid surface. The solder oxide to be removed is removed out of the bath (see FIG. 2).

Next, the bucket 3 filled with the solder liquid 21 and immersed in the solder bath 2 is raised to the outside of the solder liquid 21 by the activation of the lifting / lowering means holding the support arm 34, and is moved to the transport guide 7. It is brought directly below the printed wiring board 6 carried along (see FIG. 3).

In this rising process, the solder liquid 21 in the bucket 3 flows out from the solder exposure port 31 until the horizontal position of the solder exposure port 31 and the solder liquid level of the solder pumping port 30 are at the same horizontal position (liquid level). Equilibrium). Since the horizontal position of the stopper 33 of the flap 31f is higher than the solder exposure port 31, the solder liquid 21 is settled up from the solder exposure port 31 by the surface tension.

In this state, the solder exposure port 31 is made to approach the soldering position of the printed wiring board 6 and
When the float 4 is lowered and entered into the solder liquid 21 by the activation of the lifting / lowering means connected to the solder exposure port 3,
The swelling amount of the solder liquid 21 from 1 becomes large and comes into contact with the soldering location (see FIG. 4).

Next, while applying longitudinal vibration to the float 4 by vibrating means to propagate the longitudinal vibration to the solder liquid 21, the float 4
Is raised, the level of the solder liquid in the bucket 3 is lowered by the amount that the float 4 has entered the solder liquid 21, and the printed wiring board 6 and the solder liquid 21 are separated. The bucket 3 may be lowered with the float 4 rising, or only the bucket 3 may be lowered with the float 4 fixed. Separation while vibrating promotes sharp separation between the contact portion and the solder exposure port 31, and can prevent the occurrence of stringing.

When the soldering is completed, the bucket 3 is immersed again in the solder liquid 21 of the solder tank 2. At this time, the solder liquid 21 enters through the solder exposure port 31 provided at the lowest horizontal position. Become. Since the opening area of the solder exposure port 31 may be large or small according to the requirements of the printed wiring board 6, if the solder liquid 21 flows only from the solder exposure port 31, the gap in the bucket 3 is temporally reduced. Cannot be satisfied.

If the solder liquid continues to sink, when the solder liquid level reaches above the lower end of the inlet 32, the flap 32f is
And is swung to the inside of the bucket 3. As a result, a gap is formed between the stopper 33 and the solder liquid 21 flowing smoothly into the packet 3 (see FIG. 5).

Further, when the bucket 3 sinks, the solder liquid 21 also flows from the solder pumping port 30, but since the inside of the bucket 3 is almost already filled with the solder liquid 21 flowing from the flap 32f, a large amount of solder liquid Does not flow at once. Therefore, it is possible to suppress the danger of jumping when the solder flows in and the suction of oxides or the like that become obstacles by disturbing the surface of the solder liquid 21.

The above steps are performed as a series of steps, and by repeating these steps, the soldering process of the printed wiring board 6 sequentially sent along the transport guide 7 is performed.

[0038]

Other Embodiments In the present embodiment, the arrangement of the inlet, the intrusion of the float between the inside and the outside of the solution, and the application of longitudinal vibration to the float are not limited to this. Any number including at least one is acceptable.

The shape and mechanism of the valve mechanism are not limited to those in the present embodiment as long as they have the same function. Further, the shape of the float is not limited to the shape of the present embodiment as long as it has a similar function.

Next, as shown in FIG. 6, the above-described bucket 3 is formed by separately forming a bucket base 80 and a cylindrical base (hereinafter referred to as "base") 81 for forming a solder exposure port, and assembling them. Alternatively, the bucket 8 may be formed. That is, the bucket base 80 includes the solder pumping port 30 and the inflow port 32 having the same configuration as that of the above-described embodiment, and extends from the bottom of the solder pumping port 30 so as to communicate with the hollow portion 82 in the lateral direction.
Having. The hollow portion 82 has an outer upper surface 82u formed as a substantially horizontal flat surface and has a desired area.

On the other hand, the base 81 has a desired upper end opening shape and is formed in a bottomed cylindrical shape with only the upper part opened or a cylindrical shape with a vertical opening. And this base 8
1 has a mounting flange 81f from the bottom to the inside.
And an outer flange base 81o having an outer flange 81f formed therein. Note that the height of the base 81 is the outer upper surface 82u.
When installed at the upper end, the horizontal position of the upper end opening is
Is set to be lower than the horizontal position of the lower end of.

By configuring the bucket 8 as described above, the base 81 is arranged and fixed at an appropriate position on the outer upper surface 82u (a position corresponding to the soldering position of the printed wiring board 6). For this fixing, for example, as shown in the figure, a method of penetrating the mounting bolt 83 through the flange 81f may be used, or an appropriate fixing means such as welding may be used. After being fixed, a drill 84 is inserted from the bottom of the base 81 to make a hole 85 in the outer upper surface, so that the hollow portion 82 of the bucket 8 and the base 81 communicate. Thereby, the base 81
Will function as the solder exposure port 31.

[0043]

The present invention has the following effects. That is, by providing the inflow port provided with the valve mechanism, it is possible to avoid agitation in the bucket due to rapid inflow from the solder pumping port. That is, since the inflow port by the valve mechanism is formed on the side surface of the solder pumping port, a smooth inflow into the bucket is performed therefrom. Generation and mixing of the solder oxide floating on the surface into the bucket can be effectively prevented. Therefore, it is possible to perform a more reliable soldering operation in which the defective rate is remarkably reduced.

Also, by providing a float that moves back and forth between the inside and outside of the solution in the bucket, the amount of solder exposure from the solder exposure port can be adjusted more accurately than the natural blowout due to liquid level balance in the bucket. Can be performed.

Further, since the vertical vibration of the float moving between the inside and outside of the solution in the bucket applies a small vertical vibration to the solder liquid surface at the solder exposure port, the solder breakage at the time of separation from the soldering position is prevented. It can be performed appropriately, and the stringing of the solder, which has conventionally been a problem, can be almost completely prevented.

Further, in forming the bucket, the bucket base and the base are formed separately, and the base is fixed to the position of the soldering position later, so that the bucket base has versatility. Thus, it is possible to quickly cope with the arrangement of various patterns of the solder exposure port.

[Brief description of the drawings]

FIG. 1 is an overall perspective view schematically showing the present embodiment.

FIG. 2 is a side sectional view showing an operation state of the present embodiment step by step.

FIG. 3 is a side sectional view showing an operation state of the embodiment in a stepwise manner.

FIG. 4 is a side sectional view showing the operation state of the present embodiment step by step.

FIG. 5 is a side sectional view showing an operation state of the present embodiment step by step.

FIG. 6 is a cross-sectional side view showing another example of forming a bucket used in the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pumping type soldering apparatus 2 Solder tank 21 Solder liquid 3 Bucket 30 Solder pumping port 31 Solder exposure port 32 Inflow port 4 Float 5 Squeegee 6 Printed wiring board 7 Transport guide 8 Bucket 80 Bucket base 81 (tubular) base

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B23K 1/08 B23K 3/06 H05K 3/34 508

Claims (7)

(57) [Claims] 1. A bucket having an upwardly open solder pumping port and a solder exposure port opened upward below a horizontal position of the pumping port is moved up and down between the inside and outside of a molten solder liquid stored in a solder tank. A soldering device that performs soldering by bringing a solder liquid exposed from a solder exposure port into contact with a predetermined portion of a printed wiring board that has been conveyed and moved. A float-type soldering device, wherein a float having a predetermined volume that is moved as required by the method is arranged. 2. A pumping type soldering apparatus according to claim 1, wherein a vibration means for applying a vertical vibration to the float is mounted. 3. An inflow port which is open to the side at an intermediate position between the horizontal position of the solder pumping port and the horizontal position of the solder exposure port, the inflow port being capable of inflowing the solder liquid only in the bucket inward direction. 3. The pumping-up soldering device according to claim 1, further comprising a valve mechanism that performs the pumping. 4. A method of forming a solder exposing port, comprising fixing a cylindrical base having a predetermined opening shape and opening at least upward at a desired position of a bucket base where only a solder pumping port is formed; 4. The pumping-up soldering apparatus according to claim 1, wherein the bottom of the bucket and the inside of the bucket base are perforated to communicate with each other, so that an opening of the cylindrical die is used as a solder exposure port. 5. A bucket having an upwardly open solder pumping port and a solder exposure port opened upward below a horizontal position of the pumping port is immersed in a molten solder liquid stored in a solder tank. After the solder liquid exposed from the solder exposure port is moved up and out of the molten solder liquid, and brought into contact with a predetermined portion of the printed wiring board, the bucket is moved down and separated to perform soldering. In the method, after the solder exposure port is brought close to the soldering position of the printed wiring board, the float is moved forward and backward in the solder liquid in the bucket, and the amount of the solder liquid exposed from the solder exposure port is adjusted, so that the solder is removed. A pumping type soldering method, wherein a contact separation of a liquid to a predetermined portion is performed. 6. A pumping type solder according to claim 5, wherein, after contacting the soldering liquid with the soldering part, the soldering part is separated from the soldering liquid while applying longitudinal vibration to the soldering liquid. Attachment method. 7. The pumping soldering method according to claim 5, wherein the longitudinal vibration is applied to the solder liquid by vibrating the float.