JPH0263679A - Automatic soldering method and device - Google Patents

Abstract

PURPOSE:To prevent bridging, sagging and dripping at the point requiring soldering by executing soldering while relatively generating the flow in the direction approximately perpendicular to the feed direction of a substrate between the substrate and the molten solder ejecting from a nozzle. CONSTITUTION:The revolution of a motor 45 is transmitted via a pulley 43, a belt 44, and a pulley 42 to a lead screw 41 to revolve the screw. A nut 46 fitted to the lead screw 41 is moved in the axial direction of the lead screw 41. A moving base 34 fixed to the nut 46 moves together with a solder tank 9 on rails 39 as wheels 36 roll. The soldering of the point requiring soldering is, thereupon, executed while the solder tank 9 moves in the direction approximately perpendicular to the transporting direction of the substrate. The soldering is executed while the flow of the molten solder in the direction perpendicular to the transporting direction of the substrate is generated in this way be moving the solder tank 9 disposed with the nozzle 33 for gushing the molten solder in the direction approximately perpendicular to the transporting direction of the substrate. The final solder cutting at the end part of the substrate is executed in this way and the soldering defect is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an automatic soldering method and apparatus, and in particular to an automatic soldering method and apparatus, in which a soldering bath equipped with a nozzle for spouting molten solder is installed in a direction substantially perpendicular to the direction of board conveyance. By moving the substrate and creating a flow in a direction approximately perpendicular to the conveying direction of the substrate between the substrate and the molten solder spouted from the nozzle, bridging, icicles, and splatter at the required soldering points can be prevented. The present invention relates to a method and apparatus for automatic jet soldering.

Conventional technology Conventional jet-type automatic soldering is a method and apparatus in which molten solder is ejected by a molten solder pumping device from a nozzle that has an elongated, approximately rectangular opening in a direction perpendicular to the direction of conveyance of a board on which electronic components are mounted. Products that perform soldering using a solder flow were in practical use. However, when the soldering is performed using a method and an apparatus, as shown in FIGS. 6 and 7, when the lower surface 2C of the substrate 2 and the molten solder l spouted from the nozzle separate,
That is, when the solder breaks, as shown in FIG. 7, the molten solder 1 gradually separates from the ends 2a in the width direction of the board 2 toward the center part 2b, and finally completely separates at the center part 2b. , Bridges, icicles, and bumps are likely to occur in the widthwise central portion 2b, and it has been difficult to completely prevent these.

In such soldering, defective points 5 can only be detected by inspection after automatic soldering is completed and corrected manually using a soldering iron, which requires a lot of man-hours for inspection and correction. However, it had the disadvantage of reducing work efficiency. Furthermore, soldering has the disadvantage that the quality of the product is degraded due to errors in finding defective parts 5 and incomplete correction.

To explain in more detail the cause of defects in such soldering, the board 2 is transported while being held at the end 2a, but due to the weight of the board 2 and the weight of the electronic components mounted on the board 2, the board 2 falls downward. Although it tends to warp convexly, the lower surface 2C of the board 2 is further heated by a preheater (not shown) prior to soldering.
is preheated, and during soldering, the molten solder 1 comes into contact with the lower surface 2C of the substrate 2, and only the lower surface 2C is heated and thermally expands, so the warping is accelerated and the center part 2b of the substrate 2 is the most heated. It gets lower. Due to the main causes mentioned above, when solder breaks,
The final solder cutting is performed at the center portion 2b of the board 2. On the other hand, as shown in FIG. 6, a large number of soldering points 3 are arranged on the lower surface 2C of the board 2, and the gaps 4 between the soldering points 3 in the width direction of the board 2 are arranged in the lower surface 2C of the board 2. With the increase in packaging density, the gap has become extremely small, and the smallest gap 4 often has a Q of about 2 ms.

Therefore, when the solder breaks, if the molten solder 1 concentrates in one location, a defective location 5 will occur in soldering such as a bridge. In particular, when the two soldering points 3 with narrow gaps 4 on both sides of the center part 2b of the board 2 are arranged, the two soldering points should be soldered at the same time with molten solder 1. It is easy to cause burrs and burrs. Further, if one soldering point 3 is arranged in the central portion 2b of the substrate 2, the molten solder 1 will concentrate on the soldering point 3, resulting in icicles and splatters.

Purpose The present invention has been made in order to eliminate the drawbacks of the prior art described above, and its purpose is to provide a board transport device that transports the board with the part required for soldering facing downward; The solder tank is equipped with a solder tank equipped with a nozzle that spouts molten solder upward, and a solder tank moving device that reciprocates the solder tank in a direction substantially perpendicular to the board conveyance direction. By soldering while creating a flow in a direction substantially perpendicular to the conveying direction of the board relative to the board, the molten solder is prevented from concentrating in the center of the board when the molten solder breaks. This also eliminates soldering defects such as bridges, icicles, and bumps, and ensures good soldering performance.

Furthermore, it is possible to improve work efficiency by eliminating the need for manual solder correction work, and to prevent quality deterioration due to inspection omissions or correction errors.

Configuration In short, the method of the present invention (claim 1) moves a solder bath equipped with a nozzle for spouting molten solder in a direction substantially perpendicular to the direction of conveyance of the substrate, and directs the flow of molten solder in the direction perpendicular to the direction of conveyance of the substrate. This method is characterized by soldering while creating a flow.

In addition, the method of the present invention (claim 3) is characterized in that a solder tank provided with a nozzle for spouting molten solder is arranged in synchronization with a substrate transport device that transports the substrate in a direction perpendicular to the transport direction of the board, and at a transport speed of the board. The present invention is characterized in that soldering is carried out while moving the molten solder at a speed substantially equal to that of the board, and causing a flow of molten solder in a direction of about 45 degrees relative to the direction of conveyance of the board.

The apparatus of the present invention (claim 4) further comprises: a substrate transport device that transports the board with the part required for soldering facing downward; a solder tank equipped with a nozzle that spouts molten solder upward; a solder bath moving device that reciprocates the substrate in a direction substantially perpendicular to the direction of conveyance of the substrate, and a flow in a direction substantially perpendicular to the direction of conveyance of the substrate relative to the substrate and molten solder spouted from the nozzle is provided. This feature is characterized in that it is configured to cause this to occur.

The present invention will be explained below based on embodiments shown in the drawings. 1st
Referring to FIG. 3, an automatic soldering device 6 according to the present invention includes a substrate transport device 8, a solder tank 9, and a solder tank moving device 10.

The substrate conveyance device 8 conveys the substrate 2 in the direction of arrow A while holding the substrate 2 at the end portion 2a, and has two sets of chain conveyor hairs 11 arranged in parallel. The chain converter 11 is driven by a motor 12 via a heald 13, and as the motor 12 rotates, the shaft 1
It moves by being wrapped around a sprocket (not shown) that rotates around 4.

The solder tank 9 is composed of a primary solder tank 15 and a secondary solder tank 16, in which molten solder 1 melted by a heater (not shown) is stored, and the molten solder 1 is pumped. Impellers 18 are provided for each. The impeller 18 is configured to rotate in bearings (not shown) fixed to the solder baths 15 and 16, and has a pulley 1 at one end.
9 is manufactured integrally with a shaft 20 to which it is fixed. A belt 24 is wound between the pulley 19 and a motor pulley 23 fixed to the rotating shaft 22 of the motor 21.
1 rotation is transmitted to the impeller 18.

The nozzle 25 of the primary solder tank 15 has a substantially rectangular opening 26 that opens upward, and is configured to spray upward the molten solder l that is pumped by the rotation of the impeller 18. Further, in the opening 26 of the nozzle 25, a plurality of parallel rotary plates 28 having a diameter of about 91 cm and a thickness of about 1 fin and having a plurality of recesses in the normal direction, for example, three notches, are arranged at intervals of 3N or more. A rotating shaft 29 having a diameter of about 5 fins is disposed over the entire length, and the rotating shaft 29 is connected to a rotating shaft 31 of a motor 30 so that its upper surface faces in a direction opposite to the conveyance direction of the substrate 2 ( (counterclockwise in Fig. 2).

The secondary solder tank 16 is provided with a nozzle 33 having a substantially rectangular opening 32, through which the molten solder 1 is pumped by the impeller 18.
It is configured to eject upwards.

The solder tank moving device 10 is composed of a moving table 34 and a driving device 35, a solder tank 9 is fixed above the moving table 34, and four wheels 36 are arranged at the lower end. The automatic soldering device 6 rolls on a rail 39 fixed to the base 38 of the device 6 so that it can smoothly reciprocate in the direction of arrow B or C.

The drive device 35 includes, for example, a bearing 40 fixed to a base 38.
Boo IJ4 is attached to the lead screw 41 which is rotatably supported by the
The rotation of the motor 45 is transmitted through the rotation shaft 47 of the motor 45 by the heald 44 wound around the motors 2 and 43. A nut 46 having the same lead as the lead screw 41 is fitted into a part of the lead screw 41, and the nut is fixed to the movable table 34.

Further, in the automatic soldering device 6, a known fluxer 48, a preheater 49, and a board cooling fan 50 are respectively disposed at predetermined positions.

The method of the present invention (claim 1) moves the solder bath 9 equipped with the nozzle 33 for spouting the molten solder l in a direction substantially perpendicular to the direction of conveyance of the substrate 2. This is a method of soldering while causing a flow of molten solder 1.

Further, the method of the present invention (claim 3) includes a nozzle 3 that spouts molten solder 1 in synchronization with a substrate transport device 8 that transports the board 2.
The solder bath 9 in which solder 3 is disposed is moved in a direction perpendicular to the conveying direction of the substrate 2 and at a speed substantially equal to the conveying speed of the substrate 2, and the molten solder 1 is moved in approximately 456 directions relative to the conveying direction of the substrate 2. This is a method of soldering while creating a flow.

Function The present invention is constructed as described above, and its function will be explained below. 1 to 3, the solder in the solder bath 9 is heated and melted by energizing a heater (not shown). When the power of the motor 2I is turned on and the motor 21 rotates, the impeller 18 is rotated in one direction via the rotating shaft 22, pulley 23, heald 24, pulley 19, and shaft 20, and the melting in the solder tank 9 is caused. Solder 1 is ejected upward from nozzles 25 and 33. At the same time, motor 3
0 also starts and rotates the rotating shaft 29 in one direction (counterclockwise in FIG. The wave crests of the molten solder 1 are blown up from the gap, and the wave crests of the molten solder 1 alternately generate small wave crests and large wave crests, thereby making it possible to extremely efficiently eliminate gas generated during soldering of chip components.

On the other hand, when the chain conveyor 11 is driven by the motor 12, the substrate 2 moves at a predetermined speed in the direction of arrow A while the end portion 2a is held by the chain conveyor 11, and the fluxer 48 and preheater 49 move the substrate 2 to the lower surface 2C. The soldering process is completed at the location 3 and reaches the position of the solder tank 9.

Referring also to FIGS. 4 and 5, the molten solder 1 spouted from the nozzle 33 comes into contact with the required soldering points 3 of the board 2 to perform soldering, but the rotation of the motor 45 causes the pulley 43 to 44, the force is transmitted to the lead screw 41 via the pulley 42 and rotates it, so that the NAND 46 fitted to the lead screw 41 is moved in the axial direction of the lead screw 41. Therefore, the movable table 34 to which the NAND 46 is fixed moves in the direction of the arrow B or C as the wheels 36 roll on the rails 39 together with the solder tank 9. In other words, the board 2 is moved in the direction of arrow A, and the solder bath 9 is moved in a direction (approximately perpendicular to the direction of transport of board 2 (direction of arrow A)).
While simultaneously moving in the direction of arrow B or C, soldering is performed at point 3 where soldering is required. That is, in FIG. 3, soldering is performed while the board 2 is moved obliquely from the position shown by the solid line to the position shown by the imaginary line relative to the solder bath 9, so that the molten solder spouted from the nozzle 33 1 is soldered while producing a flow in a direction substantially perpendicular to the conveying direction relative to the substrate 2. In FIG. 5, when the solder bath 9 is moving in the direction of arrow B, the solder breakage occurs because the molten solder 1 flows in a direction approximately perpendicular to the substrate 2. In FIG. 5, it starts from the left end 2e of the substrate 2, gradually progresses to the right, and ends at the right end 2d of the substrate 2. This prevents the molten solder 1 from concentrating on one point on the board 2 when the solder breaks, even if the board 2 is curved downward. Perfect soldering can be performed without causing defects such as icicles and bumps.

Furthermore, the conditions for solder breakage are determined by the conveyance speed of the board 2 and the movement speed of the solder tank 9 in a direction approximately perpendicular to the conveyance direction of the board 2, so conventional automatic soldering can be performed by arbitrarily adjusting these two speeds. It becomes possible to set optimal solder break conditions, which was not possible with other devices. According to many experiments, when the transport speed of the board 2 and the transport speed of the solder bath 9 are set to be approximately equal, that is, while the flow of molten solder l is generated at approximately 45 degrees relative to the transport direction of the board 2, It was found that the best soldering can be achieved when soldering.

In addition, in the above embodiment, the solder tank moving device 10 is
Although the description has been made assuming that the lead screw 41 is used, this is not limited to the use of the lead screw 41, and a linear motion mechanism such as a fluid pressure cylinder may be used. Further, it is preferable that the direction of movement of the solder tank is automatically and alternately switched in the directions of arrows B and C. By doing so, work efficiency can be further improved.

Effects As described above, the present invention provides a substrate transport device that transports the board with the soldering point facing downward, a solder tank equipped with a nozzle that spouts molten solder upward, and a solder tank that transports the board with the soldering point facing downward. a solder bath moving device that reciprocates in a direction substantially perpendicular to the direction of conveyance of the substrate, and a solder tank moving device that moves the solder bath reciprocally in a direction substantially perpendicular to the direction of conveyance of the substrate, and a solder tank moving device that moves the solder tank reciprocally in a direction substantially perpendicular to the direction of conveyance of the substrate, and a solder tank moving device that moves the solder tank reciprocally in a direction substantially perpendicular to the direction of conveyance of the substrate. This prevents molten solder from concentrating on the widthwise center of the board when the solder breaks.
The final solder break is performed at the edge of the board, which has the effect of eliminating soldering defects such as bridges, icicles, and bumps. Moreover, this makes it possible to improve work efficiency by eliminating the need for manual solder correction work, and has the effect of preventing quality deterioration due to inspection omissions and correction errors.

[Brief explanation of the drawing]

1 to 5 relate to embodiments of the present invention; FIG. 1 is a plan view showing the entire device for automatic soldering, FIG. 2 is a perspective view of the main parts of the device for automatic soldering, and FIG. is a front view showing the relative positional relationship between the board and the solder tank, Fig. 4 is a plan view showing the locations where soldering is required formed on the bottom surface of the board, and Fig. 5 is a plan view showing the locations where soldering is required in the soldering state. FIGS. 6 and 7 are schematic diagrams showing the state of the flow of molten solder, and FIGS. 6 and 7 are related to conventional examples. FIG. 1 is a schematic diagram showing a state in which molten solder flows such that a bridge is formed at the center of the bottom surface of the substrate. (2) is molten solder, 2 is a substrate, 3 is a location where soldering is required, 9 is a solder tank, 10 is a solder tank moving device, and 25.33 is a nozzle. Patent applicant Yokota Machinery Co., Ltd.

Claims (1)

[Scope of Claims] 1. A solder tank equipped with a nozzle for spouting molten solder is moved in a direction substantially perpendicular to the direction in which the board is conveyed, and while a flow of molten solder is generated in a direction perpendicular to the direction in which the board is conveyed. An automatic soldering method characterized by soldering. 2. The automatic soldering method according to claim 1, wherein the moving speed of the solder bath and the conveying speed of the substrate are set to be substantially equal. 3. A solder bath equipped with a nozzle for spouting molten solder is moved in a direction perpendicular to the direction of conveyance of the substrate and at a speed substantially equal to the conveyance speed of the substrate in synchronization with a substrate conveyance device that conveys the substrate. Approximately 45 mm relative to the conveying direction of
An automatic soldering method characterized by soldering while generating a flow of molten solder in the ° direction. 4. A board transport device that transports the board with the soldering point facing down, a solder tank equipped with a nozzle that sprays molten solder upward, and a board that reciprocates the solder tank in a direction substantially perpendicular to the transport direction of the board. and a solder tank moving device for moving the solder tank, and is configured to relatively create a flow between the substrate and the molten solder spouted from the nozzle in a direction substantially perpendicular to the conveying direction of the substrate. Automatic soldering equipment.