JPH035909B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an automatic soldering method and apparatus,
In particular, a nozzle that sprays molten solder onto the bottom surface of the substrate by disposing a jet solder bath tilted in a horizontal plane with respect to the direction of conveyance of the substrate, and conveying the substrate tilted in a direction perpendicular to the direction of conveyance. An automatic soldering method and device that makes it possible to perform soldering with good soldering performance by making the distance from the top surface substantially equal and making the contact conditions between the soldering part and the molten solder the same over the entire length of the board. Regarding.

Prior Art As shown in FIGS. 8 and 9, a conventional automatic soldering method and apparatus uses molten solder from a nozzle 2 that is elongated and has an approximately rectangular opening in a direction perpendicular to the direction of conveyance of a board 1 on which electronic components are mounted. A device that performs soldering using molten solder 3 spouted out by the action of a pressure feeding device has been put into practical use.

However, in soldering using the soldering method and apparatus, when the lower surface 1c of the substrate and the molten solder 3 spouted from the nozzle 2 are separated from each other, that is, when the solder breaks, as shown in FIGS. As shown, the molten solder 3 gradually separates from the widthwise end portion 1a of the substrate 1 toward the center portion 1b, and finally separates at the center portion 1b.
In the case of b, bridging, icicles, and bumps were likely to occur, and it was difficult to completely prevent these. Such defective soldering points 5 can only be detected by inspection after automatic soldering and corrected manually using a soldering iron, which requires a large number of man-hours for inspection and correction. However, there were drawbacks that reduced work efficiency. Also, the soldering defective location 5
There were defects in the quality of the product due to errors in discovery and incomplete corrections.

To explain in detail the cause of the soldering failure, the board 1 is conveyed while being held at the end 1a, but the board 1 warps downward due to its own weight and the weight of the electronic components mounted on the board 1. Although there is a tendency, the lower surface 1c of the substrate 1 is preheated by a preheater (not shown) prior to soldering, and during soldering, the molten solder 3 comes into contact with the lower surface 1c of the substrate 1, and the lower surface 1
Since only portion c is heated and thermally expanded, the warpage is further accelerated and becomes lowest at the center portion 1b of the substrate 1. Due to the above-mentioned main reasons, when solder breaks, the solder breaks at the center portion 1b of the board 1 last.

On the other hand, as shown in FIG. 8, a large number of soldering points 4 are arranged on the lower surface 1c of the board 1, and the gaps 6 between the soldering points 4 in the width direction of the board 1 are closely spaced when the circuit is mounted. has become extremely small with the increase in 0.2 at the smallest gap 6
There are many cases in which the size is about mm. Therefore, when the solder breaks, if the molten solder 3 concentrates in one place, defects such as bridging will occur. In particular, there are two soldering points 4 with narrow gaps 6 on both sides of the central part 1b of the board 1.
When the soldering points 4 are arranged in an array, a bridge is likely to occur in which the two soldering points 4 are simultaneously soldered with the molten solder 3. In addition, 1
When two required soldering points 4 are provided, as a result of the molten solder 3 being concentrated on the required soldering points 4,
Icicles and bumps will occur.

In order to solve the above-mentioned drawbacks,
997 and JP-A-59-156568 disclose a soldering method characterized in that the nozzle 2 is arranged at an angle in a horizontal plane with respect to the direction of conveyance of the substrate 1 (direction of arrow A).
In particular, in this method, it is disclosed that it is effective to incline the substrate 1 so that the moving side is open with respect to the plane from which the molten solder 3 is spouted. Although it is possible to obtain some effect in reducing the number of soldering defects 5 by cutting the solder at the end portion 1a of the board 1 by simply arranging it at an angle in a horizontal plane with respect to the transport direction of the board 1, the above-mentioned As the substrate 1 is transported, it gradually rises, so that the molten solder 3 rises in the horizontal plane.
The distance from the nozzle 2 that spouts out gradually increases as it goes downstream in the conveying direction. That is, as the board 1 is transported, the time during which the molten solder 3 is in contact with the lower surface 1c of the board gradually becomes shorter, so that the soldering conditions are different on the left and right sides of the board 1 in the transport direction.
The condition of about 3 seconds, which is the ideal contact time with the molten solder 3, was no longer satisfied, and the soldering performance varied, leaving room for improvement. Further, depending on the arrangement of the soldering points 4, even if it is effective to further increase the inclination angle between the conveyance direction of the board 1 and the nozzle 2 to prevent defective soldering points 5, increasing the angle The molten solder 3 is placed on the bottom surface 1 of the substrate 1.
There was a drawback that it could not be made larger because it would no longer make contact with c.

Purpose The present invention has been made in order to eliminate the drawbacks of the prior art described above, and its purpose is to arrange a nozzle that spouts molten solder at an angle within a horizontal plane with respect to the direction in which the substrate is transported. By tilting and transporting the board so that the distance between the top surface of the nozzle and the bottom surface of the board is approximately equal over the entire longitudinal length of the nozzle, solder chips are removed at the edge of the board. The purpose of this is to prevent the occurrence of defective soldering such as icicles and bumps, and also to enable soldering to be performed under the same soldering conditions over the entire surface of the board. The goal is to obtain good performance. Another purpose is to enable soldering at the most suitable nozzle angle for the arrangement of the soldering points, making it possible to handle any arrangement of boards and preventing the occurrence of defective soldering points. It is to be. Still another object is to constantly align the lower surface of the substrate over the entire length of the nozzle by tilting the nozzle in a direction perpendicular to the substrate transportation direction in conjunction with changing the angle of the nozzle in a horizontal plane with respect to the substrate transportation direction. The objective is to keep the distance constant and obtain stable soldering performance, and also to be able to easily change the nozzle angle. Another purpose is to prevent the occurrence of soldering defects and to improve work efficiency by eliminating the need for manual correction work.

Configuration In short, the method of the present invention (claim 1) is an automatic soldering method in which the horizontal position of a board is gradually raised as the board is transported, in which a nozzle for spouting molten solder is moved in the direction of transport of the board. The substrate is arranged to be inclined in a horizontal plane with respect to the nozzle, and the substrate is arranged to be inclined in a horizontal plane with respect to the nozzle, such that the distance between the upper surface of the nozzle and the lower surface of the substrate is approximately equal over the entire longitudinal length of the nozzle. The substrate is transported at an angle so that the downstream side of the point of contact with the substrate in the transport direction is lower.

Further, the apparatus of the present invention (claim 2) includes a substrate transporting apparatus in which the horizontal position of the substrate gradually rises as the substrate is transported, and a substrate transporting apparatus arranged at an angle within a horizontal plane with respect to the transporting direction of the substrate. and a substrate angle adjustment device that changes the inclination angle of the substrate in a direction perpendicular to the substrate transfer direction of the substrate transfer device, and the substrate is transferred by the substrate transfer device. The present invention is characterized in that the distance between the lower surface of the substrate and the upper surface of the nozzle of the jet solder tank is adjustable so that it is approximately equal to the entire length of the nozzle in the longitudinal direction.

Further, the apparatus of the present invention (claim 3) provides a nozzle for changing the angle of the nozzle with respect to the conveyance direction of the substrate in an automatic soldering method in which the horizontal position of the substrate is gradually raised as the substrate is conveyed. A jet soldering tank equipped with an angle changing device,
a substrate angle adjustment device that changes the inclination angle of the substrate in a direction perpendicular to the substrate transport direction, and by operating the nozzle angle change device and the substrate angle adjustment device in conjunction, the horizontal plane with respect to the substrate transport direction is provided. Even if the angle of the nozzle is changed within the nozzle, the distance between the lower surface of the substrate and the upper surface of the nozzle is always approximately equal over the entire longitudinal length of the nozzle. That is.

The present invention will be explained below based on embodiments shown in the drawings. In FIGS. 1 to 4, an automatic soldering device 8 includes a substrate transfer device 9, a solder bath 10, and a substrate angle adjustment device 11.

With reference to FIGS. 1 and 2, the substrate transfer device 9
1 conveys the substrate 1 in the direction of arrow A while holding the end portion 1a thereof, and two sets of chain conveyors 12 are arranged in parallel. The chain conveyor 12 is connected to a pulley 15 fixed to the shaft 14 of a motor 13 via a belt 16, and the rotation of the motor 13 is transferred to the shaft 19 through a motion transmission mechanism 18.
is transmitted to the chain guide wheel 20 which rotates around the
The chain conveyor 12 is moved.

Further, the chain conveyor 12 is disposed at an angle α such that it faces the conveying direction of the substrate 1 (direction of arrow A) and rises with respect to the horizontal line, and the angle α is variable with a handle (not shown). has been done.

The solder tank 10 includes a primary solder tank 21 and a secondary solder tank 2.
Molten solder 3 melted by a heater (not shown) is stored in both solder tanks 21 and 22, and each nozzle 25 is driven by an impeller (not shown) driven by a motor 23 and a belt 24. and 2
6, the molten solder 3 is spouted out.
The solder tank 10 also has a nozzle angle changing device 27 and is configured as follows. That is, since the solder tank 10 is fixed on a rotary table 29 disposed on a base 28, the handle 30 can be manually operated. When operated, the direction of rotation is changed by 90 degrees by the action of the bevel gear 31 and transmitted to the shaft 32, so that the rotary table 29, that is, the solder bath 10, can be rotated slowly in a horizontal plane.

Referring also to FIGS. 3 and 4, the substrate angle adjustment device 11 adjusts the inclination angle γ of a set of chain conveyors 12 in a direction perpendicular to the substrate conveyance direction (direction of arrow A).
The chain conveyor 1 is placed on a support stand 34 supported by an inclined stand 33 provided at two locations on the loading side and unloading side of the substrate 1.
2 are arranged.

The inclined table 33 is a base 35 of the automatic soldering device 8.
When the handle 38 is manually turned, the movement is transmitted to the shaft 40 via the worm gear 39, and a cam 41 is fixed to the shaft 40. The tilt table 33 is rotated in the directions of the arrows B and B', and the tilting table 33 is moved in the directions of the arrows C and C' about the hinge 36 via the guide roller 42.

Further, in the automatic soldering device 8, a known fluxer 43, preheater 44, board cooling fan 45, and exhaust duct 46 are arranged at predetermined positions.

The method according to the present invention (claim 1) is an automatic soldering method in which the horizontal position of the substrate 1 is gradually raised as the substrate 1 is transported, and the nozzles 25 and 26 for spouting the molten solder 3 are connected to each other. The upper surfaces 25a and 26a of the nozzles 25 and 26 are arranged inclined in a horizontal plane with respect to the conveyance direction of the substrate 1.
The distance between the nozzles 25 and 2 and the lower surface 1c of the substrate 1 is
In this method, the substrate 1 is transported by tilting the substrate 1 so that the contact points between the nozzles 25 and 26 and the substrate 1 to be transported are lowered on the downstream side in the transport direction.

Effects The present invention is configured as described above, and its effects will be explained below. In FIGS. 1 and 2, the solder in the solder bath 10 is heated and melted by energizing a heater (not shown). When the motor 23 is turned on and rotated, the impeller is driven to rotate via the belt 24, and the molten solder 3 is ejected from the nozzles 25 and 26.

On the other hand, when the motor 13 is energized to drive the chain conveyor 12, the substrate 1 moves in the direction of arrow A while the end portion 1a is held by the chain conveyor 12, and is subjected to flux application and preheating by the fluxer 43 and preheater 44. Soldering is performed in a solder bath 10.

Here, referring also to FIG. 5, the handle 30 is operated so that the nozzles 25 and 2
Suppose that the angle of 6 in the horizontal plane is tilted by β,
Lower surface 1c of substrate 1 and upper surface 2 of nozzles 25 and 26
Since the height of the substrate 1 increases as it goes downstream in the transport direction, the distance between the substrates 5a and 26a increases as it goes downstream in the transport direction, resulting in different soldering conditions.

Therefore, in order to make the soldering conditions the same,
Referring also to FIGS. 3 and 4, the handle 38 is rotated to rotate the cam 41, and the substrate angle adjustment device 11 is rotated about the hinge 36 to adjust the height of the left and right chain conveyors 12. By changing the angle γ, the substrate 1 is tilted by the nozzles 25, 26 and the substrate 1.
Adjustment is made by lowering the downstream side of the contact point between the substrate 1 and the nozzles 25 and 26 in the conveying direction so that the distance from the lower surface 1c of the substrate 1 to the lower surface 1c is constant. The inclination angle γ of the substrate 1 required to keep the distance between the lower surface 1c of the substrate 1 and the upper surfaces 25a, 26a of the nozzles 25, 26 constant over the entire longitudinal length of the nozzles 25, 26 is
is determined by the rising angle α in the transport direction of the substrate 1 and the inclination angle β between the transport direction of the substrate 1 and the nozzles 25 and 26,
It may be determined so that the relationship tanγ=tanα・tanβ holds true.

By doing this, the contact time with the molten solder 3 over the entire surface of the board 1 can be kept constant at about 3 seconds, which is the ideal soldering time, and it is possible to perform soldering without variation. can.

Furthermore, as shown in FIGS. 6 and 7, the nozzles 25 and 26 are inclined at an angle β with respect to the direction of conveyance of the board 1 (arrow A direction), so that the flow of the molten solder 3 is reduced. , since a flow of component is occurring in the direction perpendicular to the transport direction (in the direction of arrow D) relative to the board 1, soldering starts from the right end 1d of the board 1, gradually progresses to the left, and reaches the left end 1e. finish. Therefore, the molten solder 3 is not concentrated at one point on the substrate 1, and the occurrence of bridging, icicles, bobbles, etc. can be prevented.

In addition, in the above embodiment, the nozzle, the angle changing device, and the substrate angle adjusting device are explained as being separate, but the two devices are not limited to being separate, but can be linked to the nozzle angle changing device. The substrate angle adjustment device can be configured to be operated in conjunction according to the relational expression tanγ=tanbα・tanβ,
In this case, the nozzle 2 in the direction of conveyance of the substrate is
Even if the angles β of 5 and 26 are changed, there is no need to separately adjust the angle γ of the substrate.

Effects According to the present invention, as described above, the nozzle is arranged to be inclined in a horizontal plane with respect to the conveyance direction of the substrate, and the distance between the upper surface of the nozzle and the lower surface of the substrate is approximately equal over the entire length in the longitudinal direction of the nozzle. Since the board is conveyed at an angle so that the solder is cut off at the edge of the board, it is possible to prevent the occurrence of icicles, bumps, etc. As a result, the entire surface of the board can be soldered under the same ideal soldering conditions.
This has the effect of making it possible to obtain consistent soldering performance.

Furthermore, since the nozzle angle changing device is provided, it is possible to prevent the occurrence of soldering defects in any way the board is arranged.

In addition, since the nozzle angle changing device and the substrate angle adjusting device operate in conjunction with each other, even if the nozzle angle is changed, the distance between the nozzle and the bottom surface of the substrate is always kept constant without adjusting the tilt angle of the substrate. ,
This has the effect of providing stable soldering performance.

Furthermore, since the occurrence of soldering defects can be prevented, the efficiency of soldering work can be greatly improved.

[Brief explanation of drawings]

1 to 7 relate to embodiments of the present invention, in which FIG. 1 is a front view of an automatic soldering device, FIG. 2 is a plan view of the automatic soldering device, and FIG. 3 is the same as shown in FIG. 1. The right side view, FIG. 4 is an enlarged perspective view of the main part of the substrate angle adjustment device, FIG. 5 is a perspective view of the main part showing the mutual relationship between the nozzle and the board, and FIG. 7 is a side view showing the important soldering points and the flow state of molten solder in the soldering state, FIGS. 8 and 9 are related to the conventional example, and FIG. 8 is the center of the bottom surface of the board. FIG. 9 is a plan view showing a state in which bridging occurs in the lower surface of the substrate, and FIG. 1 is a board, 1c is a bottom surface, 3 is molten solder, 8 is an automatic soldering device, 9 is a board transfer device, 10 is a solder tank, 11 is a board angle adjustment device, 25 and 26 are nozzles, and 27 is a nozzle angle change device It is.

Claims (1)

[Scope of Claims] 1. In an automatic soldering method in which the horizontal position of a board is gradually raised as the board is transported, a nozzle for spouting molten solder is positioned within a horizontal plane with respect to the transport direction of the board. The substrate is arranged at an angle so that the distance between the upper surface of the nozzle and the lower surface of the substrate is approximately equal over the entire length of the nozzle in the longitudinal direction. An automatic soldering method characterized by transporting at an angle so that the downstream side in the transport direction is lower. 2. A substrate transfer device that gradually raises the horizontal position of the substrate as the substrate is transferred;
a jet solder tank that is arranged to be inclined in a horizontal plane with respect to the conveyance direction of the substrate and that spouts molten solder; and a substrate that changes the inclination angle of the substrate in a direction perpendicular to the substrate conveyance direction of the substrate conveyance device. an angle adjustment device, such that the distance between the lower surface of the substrate transported by the substrate transport device and the upper surface of the nozzle of the jet solder bath is approximately equal over the entire length of the nozzle in the longitudinal direction. An automatic soldering device characterized in that it is configured to be adjustable. 3. An automatic soldering device in which the horizontal position of the board gradually rises as the board is transported, which is equipped with a nozzle angle changing device that changes the angle of the nozzle with respect to the board transport direction. A tank, and a substrate angle adjustment device that changes the inclination angle of the substrate in a direction perpendicular to the substrate transport direction, and the nozzle angle change device and the substrate angle adjustment device are operated in conjunction,
Even if the angle of the nozzle in a horizontal plane with respect to the substrate transport direction is changed, the distance between the lower surface of the substrate and the upper surface of the nozzle can be adjusted so that it is always approximately equal over the entire longitudinal length of the nozzle. An automatic soldering device characterized by having the following configuration.