JPS6216739B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an automatic soldering device, and in particular to an automatic soldering device that generates flux during soldering by reciprocating the wavefront of molten solder ejected from a nozzle in the direction of movement of a printed circuit board. This invention relates to an automatic soldering device that facilitates gas discharge and provides good soldering performance even for chip parts.

Prior Art Conventionally, when soldering electronic components to a printed circuit board, flux is applied to the soldering surface, so when the flux comes into contact with high-temperature molten solder, a large amount of gas is generated, and this gas has to escape. If there is no space, the molten solder will not be able to contact the points to be soldered, resulting in poor soldering, which is particularly noticeable when soldering chip components in which no through holes are formed on the printed circuit board. In order to eliminate this drawback, conventionally, jet-type automatic soldering equipment was used, or jet-type jets and normal jets were used together, but with either method, the structure became complicated. However, sufficient soldering performance was still not achieved.

That is, as shown in FIG.
When the chip component 20 bonded to the lower surface 13a is soldered using the jet type molten solder 3, the wave crest 19 of the molten solder 3 is stationary with respect to the traveling direction of the printed circuit board 13 (direction of arrow A). Therefore, the gas G generated between the chip parts 20 stagnates between the chip parts and is not discharged until it passes through the wave crest 19, and a soldering defect occurs in the part where such gas G was present. Ta.

In order to eliminate these drawbacks, a method has been proposed in which molten solder is jetted out from multiple small holes drilled around a pipe, and the pipe is moved back and forth in a direction perpendicular to the direction of travel of the printed circuit board, but this method According to the research, the wave crest of the molten solder reciprocated in a direction perpendicular to the direction of travel of the printed circuit board, and the period of this reciprocating movement was extremely slow, about 1 second, so the gas evacuation effect could not be expected to be much, and sufficient The drawback was that soldering properties could not be obtained.

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 reciprocating motion in the traveling direction of the printed circuit board to the opening of the nozzle through which molten solder is spouted. An aperture control member that freely changes the aperture state of the nozzle is provided, and by periodically reciprocating the aperture control member in the advancing direction of the printed circuit board, the wavefront of the molten solder is caused to reciprocate periodically in the same direction. Also, when soldering chip parts, the purpose is to improve gas discharge using a single jet and dramatically improve soldering performance. Another object of the present invention is to use a pulse motor as an actuating device for the opening control member, and to control the pulse motor using a microcomputer, thereby allowing electronic components mounted on a printed circuit board to pass through the crest of a wave of molten solder. The purpose is to make the wave crest move back and forth over the electronic components many times in between, and to ensure that the generated gas is efficiently discharged. Another purpose is to freely control the reciprocating state of the wave front of the molten solder depending on the size of the printed circuit board, the size and shape of the electronic components mounted on the board, etc. by providing an input device to the microcomputer. The purpose is to make it possible to set the optimum wave front movement, and to be able to apply it to various printed circuit boards and always obtain good soldering performance. be.

Overview In short, the present invention includes an opening control member that is provided at the opening of a nozzle through which molten solder is spouted so as to be able to reciprocate in the direction of movement of the printed circuit board, and that the opening control member is periodically moved in the direction of movement of the printed circuit board. It is characterized by comprising an actuating device that causes reciprocating movement, and a control device that is electrically connected to the actuating device and controls the actuating device.

Configuration The present invention will be described below based on embodiments shown in the drawings. First, a description will be given based on the first embodiment with reference to FIGS. 1 to 10. An intermediate tank 2 is provided in the solder tank 1, and molten solder 3 is sucked up from below as shown by arrow A into the intermediate tank. As shown by arrow B, an impeller 5 is provided to feed the solder to the nozzle 4, and the impeller is rotated horizontally by a motor (not shown) to suck up the molten solder 3 from the hole 2b provided in the bottom plate 2a of the intermediate tank 2. It's summery. A rectifying plate 6 made of a mesh plate is provided at the middle part of the nozzle 4 provided at the upper part of the intermediate tank 2, and an opening control member is provided at the opening 8 of the nozzle 4 to control the opening state of the nozzle. 9 is provided, and the opening control member consists of a rotating shaft 9a rotatably supported on the edge 1a of the solder bath 1 and a flap 9b hanging downward from the rotating shaft. It is supported in the center of the nozzle 4.

For example, a pulse motor M is used as the actuator 10, and the rotation shaft 9a of the opening control member 9 is connected to the rotation shaft 11 of the pulse motor M via a coupling 12.
are directly connected to each other, so that the aperture control member 9 can be periodically reciprocated in the direction of movement of the printed circuit board 13, that is, in the directions of arrows C and D.

A control device 14 is electrically connected to the pulse motor M, and the control device uses, for example, a microcomputer to control the pulse motor M. The control device 14 is provided with a digital switch 15, which is an example of an input device that can arbitrarily change and set the movement of the opening control member 9 by manual operation. The digital switch 15 is provided with, for example, four knobs 16 and a display section 18. The knob 16A indicates the moving speed of the opening control member 9, the knob 16B indicates the amplitude, and the knob 16C indicates the stopping time at the dead center of reciprocating motion. The control device 14 controls the opening control member 9 via the pulse motor M based on the input from the digital switch.

Effects The present invention is configured as described above, and its effects will be explained below. To automatically solder, for example, a chip component 20 to a printed circuit board 13 using the device of the present invention, first operate the knobs 16A to 16D of the digital switch 15 to control the speed, amplitude, and reciprocation of the opening control member 9. Set the stopping time and vibration frequency at the dead center. Then, each display section 18 displays the set value, and at the same time the control device 14
A designated digital signal is sent to the pulse motor M based on the input. As a result, the pulse motor M rotates back and forth, and the coupling 1
The aperture control member 9 also reciprocates via the opening control member 2 . Second
In the figure, when the flap 9b of the opening control member 9 rotates in the direction of arrow C, the flow velocity of the molten solder 3 at the left opening _8L of the opening 8 of the nozzle 4 increases, and the top surface 19a of the wave crest 19 is formed at the left end. be done.
This state is the state shown in FIGS. 5 and 8.
That is, at this time, the molten solder 3 contacts only the chip component 20 on the left side, and does not contact the chip component 20 on the right side. Also, the molten solder 3 does not come into contact with the space between both chip parts 20. Therefore, the gas G generated in the space can easily escape to the right in the figure and is easily discharged.

Therefore, as shown in FIGS. 6 and 9, when the flap 9b comes to the neutral position, the opening 8 of the nozzle 4
Since the left opening 8 _L and the right opening 8 _R have the same width, the wave crest 19 becomes left-right symmetrical, and two top surfaces 19a are formed. Soldering is done.

Next, when the flap 9b rotates in the direction of arrow D as shown in FIGS. 7 and 10, the nozzle 4
The opening _8R on the right side becomes narrower, the flow velocity of the molten solder 3 in the opening _8R becomes faster, and the top surface 19a of the wave crest 19 is formed at the right end. As a result, the molten solder 3 no longer comes into contact with the left chip component 20 and the space between both chip components 20, and even if gas G is present, the gas easily escapes to the left and is discharged. become.

In this way, the flap 9b is moved by the pulse motor M.
As a result of the reciprocating rotation, the top surface 19a of the wave crest 19 of the molten solder 3 reciprocates in the traveling direction of the printed circuit board 13 at a considerable speed, for example, about 20 times per second, and the generated gas G is this wave crest 19
It is pushed out and discharged by the movement of
Since the top surface 19a is moved many times while one chip component 20 passes through the wave crest 19, the gas G is completely discharged, the soldering is performed extremely smoothly, and no soldering defects occur. It disappears.

Next, what is shown in FIGS. 11 and 12 is a second embodiment of the present invention, in which an opening control member 22 with a slit 22a that reciprocates at right angles across the opening 8 of the nozzle 4 is provided. , the rotation shaft 1 of the pulse motor M is connected to the pair of rack parts 22b of the opening control member 22.
1 through a coupling ring 12, and a pair of integral pinions 24 are meshed with each other.

In this embodiment as well, if the pulse motor M is reciprocated, the rack portion 22 is moved by the pinion 24.
Since the aperture control member 22 reciprocates in the directions of arrows E and F through the opening control member 22a, the position of the slit 22a reciprocates in the direction of movement of the printed circuit board 13, and the molten solder 3
The flow changes in the direction of arrow H or I within the nozzle 4. As a result, the wave crest 19 of the molten solder 3
The top surface 19a of the printed circuit board 13 reciprocates in the advancing direction of the printed circuit board 13, and by providing a control device 14 and an input device 15, the same results as in the first embodiment can be obtained.

Note that the opening control members 9 and 22 are not limited to the illustrated embodiment, the actuating device 10 is not limited to the pulse motor M, and the input device is not limited to the digital switch 15. .

Effects Since the present invention is configured and operates as described above, an opening control member that changes the opening state of the nozzle is provided at the opening of the nozzle through which molten solder is spouted, and the opening control member is Since it is made to move back and forth periodically in the direction of travel of the printed circuit board,
By periodically reciprocating the wavefront of molten solder in the same direction, even when soldering chip parts, a single jet can improve gas discharge and dramatically improve soldering performance. effective.
In addition, by using a pulse motor as the actuating device for the opening control member and controlling the pulse motor using a microcomputer, the electronic components mounted on the printed circuit board can be The crest of the wave can be caused to reciprocate over the electronic components, and the effect of effectively discharging the generated gas can be obtained. Furthermore, by providing an input device to the microcomputer,
The reciprocating state of the wave crest of the molten solder can be freely set depending on the size of the printed circuit board and the size and shape of the electronic components mounted on it, so the optimum movement of the wave crest can be obtained, making it suitable for various printed circuit boards. The present invention also has the advantage of being adaptable and ensuring good soldering performance at all times.

[Brief explanation of the drawing]

1 to 10 relate to the first embodiment of the present invention, in which FIG. 1 is a front longitudinal cross-sectional view of the main part of the solder tank, FIG. 2 is a side longitudinal cross-sectional view of the main part, and FIG. 3 is an opening control A schematic perspective view showing the members, actuating device, control device, and input device. Fig. 4 is a side view showing the state of soldering of chip components by a stationary wave front of molten solder. Fig. 5 shows a state in which the flap of the aperture control member is rotated to the left end. Figure 6 is a similar vertical cross-sectional view when the flap is located at the center; Figure 7 is a similar vertical cross-sectional view when the flap is rotated to the right end; Figure 8 is a plan view of the main part when the flap is rotated to the left end, Figure 9 is a plan view of the main part when the flap is located in the center, and Figure 10 is a plan view of the main part when the flap is rotated to the right end. 11 and 12 relate to the second embodiment of the present invention, FIG. 11 is a plan view of the main part, and FIG.
FIG. 2 is a longitudinal sectional view of the main part taken along arrows XII-XII in FIG. 11. 3 is molten solder, 4 is a nozzle, 8 is an opening, 9
10 is a control member, 10 is an actuator, 13 is a printed circuit board, 14 is a control device, 15 is a digital switch which is an example of an input device, 19 is a wave crest of molten solder, 19
22 is an aperture control member, and M is a pulse motor which is an example of an actuating device.

Claims (1)

[Scope of Claims] 1. An opening control member provided at the opening of a nozzle through which molten solder is spouted so as to be able to reciprocate in the direction in which the printed circuit board advances; An automatic soldering device comprising: an actuating device for reciprocating; and a control device electrically connected to the actuating device to control the actuating device. 2. The automatic soldering device according to claim 1, wherein the actuating device is a pulse motor. 3. The control device is a microcomputer including an input device capable of inputting and operating the moving speed, amplitude, stopping time at the dead center of reciprocating motion, and vibration frequency of the opening control member. The automatic soldering device according to item 1.