JPH0299268A - Method and device for automatic soldering - Google Patents

Abstract

PURPOSE:To automatically solder a circuit board which warps to project downward by soldering the circuit board while transferring the soldering points toward the transverse central part in accordance of the transportation of the circuit board and finally soldering the central part. CONSTITUTION:The circuit board 6 which is held at both transverse side parts 6a and warps to project downward moves in an arrow A direction when a chain conveyor 5 is driven by a motor. The rear surface of the circuit board 6 is treated by a fluxer 28 and a preheater 29 and the circuit board arrives at the position of a solder tank 4. The molten solder ejected from an aperture 3a of a nozzle 3 has an approximately V shape and is parallel with a horizontal line, while the circuit board 6 is so set as to rise as the circuit board is transported at a prescribed angle; therefore, the contact position of the circuit board 6 and the molten solder moves gradually toward the root part 3b of the approximate V shape of the nozzle 3 and toward the central part of the circuit board as the circuit board is transported. The circuit board is thus soldered while the circuit board is transported. Finally, the central part of the circuit board 6 is soldered by the wave top of the molten solder formed by the root part 3b of the nozzle 3. The soldering of the circuit board 6 is thus completed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an automatic soldering method and apparatus, and more particularly, the present invention relates to an automatic soldering method and apparatus, and in particular, the present invention is equipped with a substantially square-shaped nozzle that gradually becomes narrower in the direction of conveyance of the substrate, and Soldering starts from the left and right sides, and as the board is transported, the soldering is gradually moved toward the center in the width direction, and finally the center is soldered, so that the soldering becomes convex downward. The present invention relates to a method and apparatus for automatic soldering that enables soldering of warped parts of a board.

Conventional technology Conventional automatic soldering is a jet type automatic soldering device that is equipped with a conveyor device that conveys a board and a nozzle that opens in a straight line at right angles to the direction of conveyance of the board. The equipment shown is in practical use. However, in this soldering device, the top surface of the jet of molten solder that is ejected from the nozzle is linear, so the required soldering can only be soldered to a board with a flat part. It was not possible to solder curved boards such as curved boards. On the other hand, as electronic application devices have become more complex in recent years, there has been an increasing demand for soldering curved boards, and it is expected that the demand for such boards will further increase in the future. An example of an electronic application device that requires a curved substrate is a keyboard designed from an ergonomic standpoint with emphasis on operability. Since the keys of the keyboard are arranged in an upwardly curved curved shape when in use so as to fit comfortably in the operator's hand, the board on which the electronic components are mounted must also have a curved shape. Soldering of such a board could not be performed at all using conventional equipment, so the soldering had to be done manually, which was extremely inefficient. In addition, since the process is performed by humans, there is a large variation in quality and the product is unreliable. Furthermore, as electronic application equipment continues to become smaller, the mounting density of boards continues to increase, and on boards with high mounting density, the distance between adjacent soldering points may be as small as 0.2 nm. Therefore, it was impossible to manually solder a board with such high packaging density.

Purpose The present invention has been made in order to eliminate the drawbacks of the prior art described above, and its purpose is to eject molten solder from a substantially ■-shaped nozzle that gradually becomes narrower in the direction of conveyance of the board. Then, soldering is started from the left and right sides in the transport direction of the board, which is curved convexly downward in the width direction, and as the board is transported, the soldering points are moved toward the center in the width direction. By soldering at the same time and finally soldering the center part, it is now possible to automatically solder a board that is curved downward due to the soldering condition, which was previously impossible. That's true. Another object of the present invention is to automatically solder a board that is curved downward in a convex manner, thereby making it possible to perform soldering with good work efficiency and high reliability. Still another object is to enable soldering of curved substrates with extremely high packaging density, increase the degree of freedom in the shape of the substrate, and enable diversification of products.

Configuration In short, the method of the present invention (claim 1) is such that molten solder is jetted from a substantially ■-shaped nozzle that gradually becomes narrower in the direction of conveyance of the substrate, and the solder is ejected from the left and right sides of the direction of conveyance of the substrate, which is curved convexly downward in the width direction. Soldering is started from both sides, and as the board is transported, soldering is performed while moving the soldering points toward the center in the width direction, and finally the center is soldered. This is a characteristic feature.

The device of the present invention (claim 2) also includes a substrate transport device that transports the board so that the soldering point of the board is held facing downward while the board is gradually raised with respect to the horizontal line as the board is transported. , a jet-flow type solder bath equipped with a nozzle that spouts molten solder in a substantially square shape that gradually becomes narrower in the direction of conveyance of the substrate, and the solder tank is equipped with a jet-flow type solder tank equipped with a nozzle that spouts molten solder in a substantially ■ shape that gradually becomes narrower in the direction of conveyance of the substrate; In the soldering process, contact between the point and the jet of molten solder spouted upward from the approximately V-shaped nozzle starts from the left and right sides of the board in the transport direction, and as the board is transported, it gradually reaches the center in the width direction. The device is characterized in that it is configured to move toward the end.

The present invention will be explained below based on embodiments shown in the drawings. An automatic soldering device 1 according to the present invention includes a substrate transfer device 2 and a solder tank 4 provided with a substantially V-shaped nozzle 3.

In FIG. 1, the substrate conveyance device 2 uses two chain conveyors 5 arranged in parallel to transport the substrates 6 at both ends 6 in the width direction.
A is held and conveyed in the direction of the arrow. A pulley 10 is fixed to the rotating shaft 9 of the motor 8, and a pulley lO
A belt 11 is wrapped around the belt. The belt 11 is further wound around a pulley 12 and transmits the rotation of the motor 8 via a motion transmission mechanism (not shown) to a sprocket (not shown) that rotates around a shaft 13, thereby transmitting the rotation of the motor 8 to a sprocket (not shown) rotating around a shaft 13.
It is designed to operate.

Referring also to FIGS. 2 to 5, the chain conveyor 5 is inclined at an angle α so as to rise with respect to the horizontal line in the conveying direction of the substrate 6, and the angle α is variable with a handle (not shown). It is composed of The nozzle 3 has a substantially V-shaped opening 3a that spouts molten solder 14 facing upward.
It is arranged in the solder tank 4. And approximately V of the opening 3a
Inside the shape, a substantially rectangular first guide plate 3b is fixed diagonally downward in a square shape in order to smoothly flow the molten solder 14 ejected from the opening into the solder bath 4.

Further, inside the substantially V-shaped root portion 3h of the nozzle 3, a second guide plate 3C having a substantially semicircular opening shape is disposed at substantially the same height as the opening 3a. Furthermore, protrusions 3d, 3e, and 3f are fixed to the substantially V-shaped outer side of the opening 3a by bolts 15, respectively, to prevent the molten solder 14 ejected from the opening 3a from flowing out.

The solder tank 4 stores molten solder 14, and has a separation plate 4a.
It is divided into an upper tank 4b and a lower tank 4C. The separation plate 4a has an inflow hole 4d for molten solder 14 and a nozzle 3.
A hole 4e communicating with is bored. An electric heater 16 for melting the solder is disposed in a part of the solder tank 4, and a motor 18 is disposed in the other part via a mounting plate 19.

A belt 22 is wound around a pulley 21 fixed to a rotating shaft 20 of a motor 18. The belt 22 is further wound around a pulley 25 fixed to one end of a shaft 24 rotatably held in a bearing 23 fixed to the mounting plate 19, and molten solder 14 is pumped to the other end of the shaft 24. An impeller 26 is fixed thereto. Radiation fins 23a are formed in the bearing part 23 to prevent the bearing part 23 from becoming high temperature due to the heat of the molten solder 14.

In FIG. 1, an automatic soldering apparatus 1 includes a known fluxer 28, a preheater 29, and a substrate cooling fan 30, respectively, arranged at predetermined positions.

The method of the present invention (claim 1) jets out the molten solder 14 from the substantially V-shaped nozzle 3 that gradually becomes narrower in the direction of conveyance of the substrate 6, so that the substrate 6 curves downward in the width direction.
Soldering is started from both left and right sides 6a in the transport direction, and as the board 6 is transported, soldering is performed while moving the parts toward the center part 6b in the width direction, and finally the center part 6b is soldered. This is a soldering method.

Function The present invention is constructed as described above, and its function will be explained below. 1 to 5, when the power to the heater 16 is turned on, the solder in the solder tank 4 is melted by the heat generated by the heater 16, becomes molten solder 14, and is stored in the solder tank 4. When power is supplied to the motor 18 and the rotating shaft 20 of the motor starts rotating, the rotation is transmitted to the impeller 26 via the pulley 21, belt 22, pulley 25, and shaft 24. Due to the rotation of the impeller 26, the molten solder 14 flows from the upper tank 4b through the inflow hole 4d into the lower tank 4C in the direction of arrow B, but the flow velocity in the lower tank 4C is lower than the flow velocity through the inflow hole 4d. Since the kinetic energy is also very slow, the kinetic energy is mainly converted into pressure energy, and the pressure in the lower tank 4c is increased. The molten solder 14 flows slowly in the direction of arrow C, flows from the hole 4e in the direction of the arrow, flows into the nozzle 3, is ejected from the opening 3a, and is guided by the first guide plate 3b and the second guide plate 3C. The solder is then returned to the solder tank 4, and the circulation is repeated again by the action of the impeller 26.

On the other hand, when the chain conveyor 5 is driven by the motor 8, the substrate 6, which is held at both sides 6a in the width direction by the chain conveyor and is curved downward in a convex manner, moves in the direction of arrow A at a predetermined speed, and the fluxer 28 , the lower surface 6C of the substrate 6 is processed by the preheater 29 and reaches the position of the solder bath 4. Here, the fourth
As shown in the figure and FIG. 5, the molten solder 14 spouted from the opening 3a of the nozzle 3 is approximately V-shaped and parallel to the horizontal line, while the substrate 6 is conveyed at a predetermined angle α. opening 3a.
The contact between the molten solder 14 spouting out and the lower surface 6c of the substrate 6 starts from the both sides 6a of the substrate 6 due to the wave crests 14a formed at the substantially V-shaped opening end 3g, and as the substrate 6 is transported, the contact between the lower surface 6c of the substrate 6 The contact position is soldered while gradually moving toward the approximately V-shaped root portion 3h of the nozzle 3 and toward the center portion 6b of the board 6, and finally to the root portion 3h of the nozzle 3.
The wave crest 14b of the molten solder 14 formed in the substrate 6
The center portion 6b of the board 6 is soldered to complete the soldering of the downwardly curved board 6.

In the illustrated embodiment, the nozzle 3 has been described as having a substantially V-shape, but a substrate 6 having a downwardly convex arc shape, which is often used, may be used.
It is clear from the shape of the cut end of the cylinder that is cut at an angle α with respect to the axis that the optimal nozzle shape for soldering is a parabolic shape. 1, various substrates 6 with different widths can be used.
Also in soldering, the predetermined angle α when transporting the board 6
can always be kept constant.

Effects As described above, the present invention jets molten solder from a substantially V-shaped nozzle that gradually becomes narrower in the direction of conveyance of the substrate, and from both left and right sides in the direction of conveyance of the substrate, which is convexly curved downward in the width direction. Soldering is started, and as the board is transported, the soldering is performed while moving the soldering points toward the center in the width direction, and finally the center is soldered, which is different from the conventional method. It is possible to automatically solder a downwardly curved board that could only be soldered manually, and the work efficiency can be dramatically improved. In addition, manual soldering can prevent mistakes, improving the reliability of the product, and soldering can reduce the number of man-hours required to repair defective parts, so it has great economic effects.

Furthermore, it is possible to automatically solder downwardly curved boards that are mounted at high density, which would be impossible to do manually, increasing the degree of freedom in the shape of the board and making it possible to diversify products. It has the effect of

[Brief explanation of the drawing]

The drawings relate to embodiments of the present invention; Fig. 1 is a plan view showing the entire automatic soldering device, Fig. 2 is an enlarged plan view showing the solder tank, and Fig. 3 is the configuration of the solder tank and its approximately V-shape. Fig. 4 is a perspective view showing the positional relationship between the nozzle and the board, Fig. 4 is a longitudinal cross-sectional view taken along the ■-IV arrow in Fig. 2 to explain the state of soldering on both sides of the board, and Fig. 5 is a vertical cross-sectional view of the nozzle and the board. FIG. 2 is a vertical cross-sectional view taken along the line V-V in FIG. 1 is an automatic soldering device, 2 is a substrate transport device, 3 is a roughly V-shaped nozzle, 3c is a guide plate for molten solder, 3d, 3e, 3
f is a protrusion, 3h is a base, 4 is a solder tank, 6 is a board, 6
a is both side parts, and 6b is a center part.

Claims (1)

[Scope of Claims] 1. Molten solder is spouted from a substantially V-shaped nozzle that gradually becomes narrower in the direction of conveyance of the board, and soldering is performed from both left and right sides in the direction of conveyance of a board that is convexly curved downward in the width direction. , and as the board is transported, soldering is performed while moving the soldering point toward the center in the width direction of the board,
An automatic soldering method characterized in that the central portion is finally soldered. 2. A board transport device that transports the board so that it gradually rises with respect to the horizontal line as it is transported while holding the board with the required soldering points facing downward; a jet-flow type solder tank equipped with a nozzle that spouts molten solder in a substantially V-shape, and from the substantially V-shaped nozzle to the soldering point of the downwardly curved board being transported by the board transport device. Contact with the jet of molten solder spouting upward starts from both left and right sides of the board in the transport direction, and gradually moves toward the center in the width direction as the board is transported. Features automatic soldering equipment. 3. A protrusion that prevents the outflow of the jet of molten solder is formed on the outer upper surface of the approximately V-shaped nozzle, and at approximately the same height as the upper surface of the nozzle at the approximately V-shaped root portion of the nozzle, and 3. The automatic soldering apparatus according to claim 2, further comprising a guide plate for molten solder having a substantially semicircular opening on the front side in the direction of conveyance of the substrate. 4. The automatic soldering apparatus according to claim 2, wherein the substantially V-shape is a parabolic shape.