JPH05190403A - Method and apparatus for solder coating of axial lead parts - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a solder coating method and device for axial lead parts, which enables efficient and efficient solder coating work in a small-sized facility. [Structure] A transport mechanism 2 for gripping an axial lead component 1 in a horizontal posture and transporting it in a line, a roller-type flux applicator 6 arranged separately on the left and right sides of a component transport path along the transport line, and a flux applicator. A slit passage 5a provided with two sets of solder coating jigs 5 arranged side by side in the rear stage and arranged left and right, and through which a lead 1a of a component passes between an upper jig 5b and a lower jig 5c of the solder coating jig.
And the solder liquid supply hole 5 is formed in the slit passage.
The solder liquid 3 sucked up from the solder bath 4 is held through d, and the axial lead parts are attached to the flux applying section,
Two leads drawn from both sides of the part are conveyed and passed through a solder coating jig in this order, and are simultaneously solder coated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended for axial lead parts such as diodes, ceramic capacitors, and resistance elements, and a solder coating method for applying a pre-solder coating to two leads drawn out on both sides of the parts, and the solder. The present invention relates to a coating device.

[0002]

2. Description of the Related Art As a solder coating method for the axial lead parts mentioned above, a solder dipping method is generally adopted at present. As is well known, the solder dipping method is a method in which the leads of the components inserted from above are immersed in a solder bath containing a molten solder solution to coat the surfaces of the leads with solder. In addition to the solder dip method, the solder plating method is also known, but the plating method requires large-scale equipment, the management of the plating solution is difficult, and the processing of the waste plating solution involves pollution problems. Therefore, except for a large-scale mass production line, it has hardly been carried out on a small number of various types of production lines.

[0003]

The solder dipping method described above has the following problems in terms of equipment and process. In other words, (1) In order to apply the solder coating treatment to the leads of the axial lead component, it is necessary to perform the solder treatment by dividing the two leads drawn out on both sides of the component into two times, one for each side, and therefore, in the automatic production line. To continuously coat the parts, two solder baths arranged in series on the line are required, which increases the equipment cost and the installation area of the equipment. (2) Since the upper surface of the solder bath is open to the atmosphere, the surface of the solder liquid stored in the bath is susceptible to oxidation, and it is frequently necessary to insert the component leads from above and perform soldering. Since it is necessary to remove oxides on the surface with a squeegee, it is difficult to manage the solder surface including liquid level and temperature control. (3) Since the two leads drawn from the component are soldered one by one, it is necessary to turn the direction of the axial lead component upside down during the process, and the handling operation is troublesome.

The present invention has been made in view of the above points, and an object thereof is to solve the above-mentioned drawbacks of the dipping method and to carry out a solder coating work efficiently with a small equipment. It is to provide a coating method and apparatus.

[0005]

In order to achieve the above object, in the solder coating method of the present invention, an axial lead component is held in a horizontal posture while being conveyed in a line, and is pulled out from the component on the way of the conveyance route. Flux is simultaneously applied to two leads, and in the subsequent process, the leads are passed across the solder solution held in the slit passages of the two sets of left and right solder coating jigs to perform solder coating. ..

On the other hand, the solder coating apparatus of the present invention used for the above-mentioned solder coating method has a conveying means for holding an axial lead component in a horizontal posture and conveying it in a line, and a left and right side of a component moving path on the way of the conveying line. It consists of two sets of flux coating means that are distributed to each other and two sets of solder coating jigs that are distributed to the left and right side by side after the flux coating means. Inside the solder coating jig, the lead of the component crosses horizontally. A slit passage in the direction is formed to hold the solder liquid in the slit passage.

Here, there is the following configuration as an embodiment of the solder coating apparatus. First, the flux applying means is set to a flux applying roller that comes into contact with the component leads,
And a brush and a flux solution bath in which the lower part of the roller is immersed. Also, the solder coating jig is a combination of an upper jig and a lower jig that face each other vertically with a horizontal slit passage across which the component leads cross.
In addition, the lower jig is provided with a capillary-shaped solder liquid supply hole that penetrates the jig vertically and communicates with the slit passage, and the lower portion of the lower jig is immersed in the solder liquid in the solder bath. And

In the solder coating jig described above, the narrow gap passage formed between the upper jig and the lower jig does not hold the solder liquid and the narrow solder holding surface area for holding the solder liquid. It is preferable to divide the pattern into two areas, a solder non-holding surface area with a wide gap, and gradually expand the pattern of the solder non-holding surface area from the root side of the lead in the lead longitudinal direction along the component movement direction. The jig is preferably provided with a heater that keeps the solder held in the slit passage in a molten state.

[0009]

With the solder coating apparatus having the above-described structure, first, in the solder coating jig, the solder liquid sucked up by the siphon action from the solder tank side through the solder replenishing hole formed in the lower jig is separated from the upper jig. It diffuses in the gap passage to form a solder pool. Here, the solder holding surface area in the narrow gap passage is set to a narrow gap of about 1.0 to 1.5 mm according to the lead thickness of the axial lead component, and the solder liquid is thin due to the surface tension. It is held in a solder holding surface area having a narrow gap with almost no leakage from the gap passage. Moreover, this solder pool is only slightly in contact with the atmosphere at the peripheral surface of the slit passage and is hardly oxidized.

When the axial lead component is horizontally held with respect to the solder coating device and conveyed in a line, first, the two leads pulled out from both sides of the component while the component passes over the flux coating roller. At the same time, the flux is applied by contacting the roller and brush.
Subsequently, the leads of the component pass so as to cross the solder pool in the slit passage of the solder coating jig, and in this process, the two leads are simultaneously solder-coated.

Further, in this case, the slit passage formed between the upper jig and the lower jig is divided into a solder holding surface area with a narrow gap and a solder non-holding surface area with a wide gap, and the solder is not held. By gradually expanding the pattern of the surface area from the root side of the lead in the longitudinal direction of the lead along the moving direction of the component, the lead of the component entering the slit passage from the entrance side of the jig is Passes through the solder holding surface area and moves from there to the exit side of the slit passage, the lead gradually moves from the root side to the tip toward the solder non-holding surface area. Therefore, when the lead passing through the solder pool held in the solder holding surface area of the slit passage crosses the boundary between the lead and the solder non-holding surface area having a large gap, the solder deposited on the surface of the lead is The excess amount of the liquid is attracted from the root side to the tip side of the lead by the action of surface tension, and as a result, the lead is coated with the solder in a uniform thickness over the entire length area. In other words, the same effect as that obtained by dipping the lead in the solder bath by the conventional dipping method and then gradually pulling it up to cut the solder can be obtained.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2, 1 is an axial lead part,
1a is a lead drawn from both ends of the component, and the solder coating apparatus includes a transport mechanism 2 for gripping the axial lead component 1 and transporting it in a line, a solder bath 4 filled with a molten solder liquid 3, and a lower half part. It is composed of two sets of left and right solder coating jigs 5 dipped in the solder solution 3 and placed in the solder bath, and a flux coating section 6 placed in front of the solder bath 4.

Here, the transport mechanism 2 comprises a transport chain 2a laid along the transport line, a guide rail 2b, and a gripper 2c connected to the transport chain 2a. As shown in the figure, the gripper 2c holds the axial lead component 1 in place. It is gripped in a horizontal posture (the direction of the leads 1a pulled out from both ends of the component is perpendicular to the conveying direction), and the line is conveyed horizontally from left to right in the drawing while maintaining a predetermined height position.

On the other hand, the solder coating jig 5 is made of stainless steel in consideration of wettability with the solder liquid, and separates the slit passage 5a through which the lead 1a of the axial lead component 1 enters and passes. The lower jig 5 is composed of an assembly of an upper jig 5b and a lower jig 5c which are vertically opposed to each other.
Capacitor-shaped solder solution replenishing hole 5d is formed in c by penetrating the jig up and down and opening to the slit passage 5a. Further, the upper jig 5b is provided with a heater 5e for keeping the temperature of the solder solution. There is. With this configuration, the solder liquid 3 contained in the solder bath 4 is sucked up by the siphon action through the solder liquid replenishment hole 5d of the lower jig 5c to form a solder pool in the slit passage 5a and heated by the heater 5e. The solder held in the gap passage is kept warm in a molten state. Further, the solder liquid retained in the slit passages is only slightly in contact with the ambient atmosphere on the peripheral surface of the passages, and the upper and lower surfaces thereof are the jigs 5b,
Since it is covered with 5c, it is hardly oxidized.

Further, the slit passage 5a is shown in FIGS.
As shown in, a narrow gap for holding the solder liquid 3 sucked and replenished from the solder bath 4 through the solder replenishment hole 5d (gap dimension is slightly wider than the wire diameter of the lead 1a is about 1.0 to 1.5 mm).
The solder holding surface area 5f set to No. 2 and the solder non-holding surface area 5g having a wide gap that does not hold the solder liquid are patterned into two parts. Here, the pattern of the solder holding surface area 5f is formed on the outer side of the passage so that the width (width direction of the jig) gradually decreases from the inlet to the outlet of the slit passage 5a, and conversely the solder non-holding surface. The pattern of the area 5g is formed inside the solder holding surface area 5f so as to gradually expand. In addition, P shown in FIG. 2 indicates a boundary between the solder holding surface area 5f and the solder non-holding surface area 5g, and the boundary P is used as a boundary between the solder holding surface area and the solder non-holding surface area. A step difference is formed on each of the surfaces as shown in FIG. Further, the boundary P is curved so as to draw a parabola from the entrance to the exit of the slit passage 5a.

Next, the flux applying section 6 comprises a flux solution tank 6a, two sets of left and right flux applying rollers 6b soaked in the tank, and a brush 6c installed on the peripheral surface of the roller 6b. The two sets of rollers 6b are arranged with their height positions aligned with the movement loci of the leads 1a of the axial lead component 1.

Next, a solder coating method for the axial lead component 1 performed by the solder coating apparatus having the above-mentioned structure will be described. When the axial lead component 1 is gripped by the gripper 2c of the transport mechanism 2 and transported in a line, first, when the axial lead component 1 passes through the flux coating section 6 arranged on the transport line, the two lead-out parts pulled out to both ends of the component. Lead 1a simultaneously rubs through between the roller 6b and the brush 6c, where the flux is applied to the lead 1a. Subsequently, the lead 1a enters the slit passage 5a of the solder coating jig 5 arranged in the subsequent stage, and the two leads 1a are simultaneously soldered in the process of traversing the solder pool held in the slit passage. Coated.

In this case, in the slit passage 5a, the solder holding surface area 5f and the solder non-holding surface area 5g having a narrow gap described in FIG. 2 are formed so as to divide the passage 5a into the inner and outer parts along the component moving direction. Thus, the lead 1a that has entered the slit passage moves across the solder holding surface area 5f having a narrow gap and moves to the solder non-holding surface area 5g having a wide gap. As a result, when the lead 1a crosses the boundary P between the surface regions 5f and 5g, the excess amount of the solder liquid deposited on the surface of the lead 1a is sucked from the root side to the tip side of the lead by the action of surface tension. As a result, the lead 1a that has exited the jig 5 is coated with solder with a uniform thickness over the entire length thereof. In other words, the same effect as that obtained by dipping the lead in the solder bath by the conventional dipping method and then gradually pulling it up to cut the solder can be obtained. A finished state by this solder coating method is shown in FIG. 4A, and in the figure, 7 indicates a solder coating layer coated on the lead 1a. On the other hand, FIG. 4 (b) shows a finished state by an experiment in which solder coating is performed using a jig in which the entire surface of the slit passage is made into a narrow gap and a solder pool is formed. The solder coating layer 7 is not evenly formed along the longitudinal direction of the lead 1a because the entire length of the solder is suddenly released from the solder pool formed in the jig, and uneven bumps commonly called solder horns and dowels are formed. You can see how it is being done. Moreover, if the bumps as described above are formed on the solder coating layer 7, the bumps of the solder become an obstacle when the axial lead component is inserted and mounted in the printed wiring board, which is not preferable.

[0019]

As described above, according to the present invention, two leads drawn out to both sides of the axial lead component can be simultaneously subjected to the solder coating treatment without changing the transporting posture of the axial lead component. The work efficiency is greatly improved compared to the method, and the solder coating device can be made smaller and more compact to save space in the equipment. Further, the solder pool held in the slit passage in the jig is hardly oxidized by only contacting only the peripheral surface portion of the passage with the ambient air, and the management of the solder liquid is simplified.

Further, regarding the slit passage formed in the solder coating jig, the solder holding surface area with a narrow gap and the solder non-holding surface area with a wide gap are skillfully distributed in the passage to form a pattern. The solder coating layer can be formed in a uniform finished state by depositing the solder solution on the entire length of the area without excess or deficiency.

[Brief description of drawings]

FIG. 1 is a sectional view of the structure of a solder coating apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is an enlarged cross-sectional view taken along line XX in FIG.

FIG. 4 is a view showing a finished state in which an axial lead component is solder-coated, and FIG. 4A shows a solder holding surface area having a narrow gap and a solder non-holding surface area having a wide gap formed in a slit passage in a jig. Finished state diagram with the solder coating jig, Fig. 6 (b) is the finished state diagram with the jig in which the entire area of the slit passage is the same.

[Explanation of symbols]

 1 Axial lead parts 1a Lead 2 Transport mechanism 2a Transport chain 2c Gripper 3 Solder liquid 4 Solder tank 5 Solder coating jig 5a Slit passage 5b Upper jig 5c Lower jig 5d Solder liquid supply hole 5e Heater 5f Solder holding surface area 5g Solder non-holding surface area 6 Flux application part 6a Flux solution tank 6b Flux application roller 6c Brush

Claims (6)

[Claims] 1. A solder coating method for an axial lead component, wherein two leads drawn out on both sides of the component are simultaneously solder-coated in one step, and the component is line-transported while holding the component in a horizontal posture, and its transport path. Flux is simultaneously applied to the two leads pulled out from the component on the way, and in the subsequent process, the leads are passed across the solder solution held in the slit passages of the two solder coating jigs on the left and right. A solder coating method for axial lead parts, characterized by performing solder coating. 2. A solder coating apparatus for use in the solder coating method according to claim 1, wherein the lead means holds the axial lead component in a horizontal posture and conveys it in a line, and a component moving path on the way of the convey line. It consists of two sets of flux applying means distributed to the left and right sides, and two sets of solder coating jigs arranged side by side after the flux applying means, and the lead of the component is inside the solder coating jig. A solder coating device for an axial lead component, characterized in that a horizontal slit passage is formed across and a solder liquid is retained in the slit passage. 3. The solder coating apparatus according to claim 2, wherein the flux applying means comprises a flux applying roller that contacts the leads of the component, a brush, and a flux solution tank in which the lower portion of the roller is immersed. A solder coating device for axial lead parts. 4. The solder coating apparatus according to claim 2, wherein the solder coating jig is composed of a combination of an upper jig and a lower jig which are vertically opposed to each other with a horizontal slit passage across the component leads. In addition, the lower jig has a capillary-shaped solder solution supply hole that penetrates the jig vertically and communicates with the slit passage, and the lower part of the lower jig is immersed in the solder solution in the solder bath. This is a solder coating device for axial lead parts. 5. The solder coating apparatus according to claim 4, wherein the narrow gap passage formed between the upper jig and the lower jig holds a solder holding surface area with a narrow gap for holding the solder liquid and the solder liquid. Axial lead parts characterized by being divided into two areas, a solder non-holding surface area with a wide gap, and the pattern of the solder non-holding surface area being gradually expanded from the root side of the lead in the lead longitudinal direction along the part moving direction. Solder coating equipment. 6. The solder coating apparatus according to claim 4, wherein the upper jig of the solder coating jig is provided with a heater for keeping the solder held in the slit passage in a molten state. Parts solder coating equipment.