JP2930350B2 - Solder jet device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder jet device effective for use in a jet type soldering method.

2. Description of the Related Art In recent years, a jet-type soldering method has been widely used as a joining technique between a printed wiring board and an electronic component.

Hereinafter, an example of the above-described conventional jet-flow soldering method will be described with reference to the drawings.

4 and 5 show the configuration of the solder jet device. In FIG. 4, reference numeral 1 denotes a printed wiring board, and reference numeral 2 denotes a warp prevention bracket, which is mounted near the center of the printed wiring board 1. Reference numeral 3 denotes a solder jet blade, and 4 denotes a motor for driving the solder jet blade 3. Reference numeral 5 denotes a solder jet nozzle for jetting the solder in the solder tank 7 upward, and reference numeral 6 denotes a jet wave jetted from the nozzle 5. A is the transport direction of the printed wiring board 1. In FIG. 5, reference numeral 8 denotes a transport claw.
Is transported.

The operation of the conventional solder jet device configured as described above will be described below.

First, when the motor 4 is driven, the solder jet blades 3 rotate to generate a solder flow, and the solder jet nozzle 5 generates a solder jet wave 6, which is sequentially soldered from the front surface of the printed wiring board 1. In order to prevent the printed wiring board 1 from lowering at the time of soldering, the warpage prevention metal fitting 2 is attached as described above. As a result, the immersion depth of the printed wiring board 1 in the jet wave 6 becomes constant, and uniform soldering becomes possible. As another means for preventing the printed wiring board 1 from slewing, a wire may be stretched at the position of the anti-sludge fitting,
Often used.

Problems to be Solved by the Invention However, in the above configuration, chip components, IC
When soldering to a high-density mounting printed wiring board on which a large number of components are mounted, there is a problem that reliability at the time of soldering cannot be obtained. Hereinafter, the problems described above will be described with reference to the drawings.

FIG. 6 shows a soldering state of a high-density mounting printed wiring board in a conventional solder jet apparatus. In FIG. 6, 9 is a large chip component and 10 is a small chip component. 11
Is a soldering land, which is a solder receiving portion on the printed wiring board 1 side. Reference numeral 12 denotes a chip electrode, which is a soldering location for 9, 10 chip components. FIG. 7 and FIG. 8 are views showing a state where the solder rides on the printed wiring board at the time of the conventional solder jet flow.

The problems of the conventional solder jet device configured as described above will be described below.

First, in FIG. 6, when soldering to a high-density printed wiring board on which a large number of chip components, ICs, etc. are mounted, the solder flow enters the soldering lands 11 of the printed wiring board 1 behind the large chip components 9. As a result, the space 13 remains, and a portion where solder bonding is not performed between the electrode 12 of the chip component and the soldering land 11 occurs. As means for preventing this problem, if the solder is blown high from the solder jet nozzle 5 to improve the contact with the soldering land 11, the state where the solder flows into the upper surface of the printed wiring board 1 at the time of starting soldering and at the time of finishing soldering Becomes FIG. 7 and FIG. 8 show a state in which the solder rides on the upper surface of the printed wiring board of the jet solder. First, in FIG. 7, when the solder blow-up from the solder jet nozzle 5 is increased, the jet wave 6 runs from the front end of the printed wiring board 1 onto the upper surface of the printed wiring board 1. In FIG. 8, the solder jet nozzle 5
When the solder blow-up from
The jet wave 6 runs on the upper surface of the printed wiring board 1 from the rear end. As described above, since the heat of the molten solder on the upper surface of the printed wiring board 1 causes the exterior deformation and performance destruction of the upper electric component, the blow-up of the solder from the solder jet nozzle 5 cannot be increased. There was a problem that soldering of the mounted printed wiring board could not be performed well.

The present invention solves such a problem, and prevents the solder from getting on the upper surface of the printed wiring board at the start and end of soldering, and can perform soldering well, and improves the reliability of soldering. The purpose is to achieve it.

Means for Solving the Problems To solve the above problems, the solder jet device of the present invention is
A solder tank for storing solder, a solder ejection nozzle for guiding the solder in the solder tank in the direction of the printed wiring board passing through the upper portion of the solder tank, and the solder tank for ejecting the solder from the solder ejection nozzle. A solder jet blade for sending out the solder in the direction of the solder jet nozzle, a solder jet level variable unit for controlling the flow rate of solder from the solder jet nozzle by changing the rotation speed of the solder jet blade in two stages, A position detection unit for detecting a position of the printed wiring board, wherein the solder jet level variable unit outputs a jet from a solder jet nozzle after a lapse of a predetermined time after the position detection unit detects the passage of the front end of the printed wiring board. A timer is provided to control the driving of the solder jet level changing unit so as to increase the flow rate of the solder and reduce the flow rate of the solder just before the rear end of the printed wiring board passes. It is.

Operation The present invention increases the flow rate of the solder jetted from the solder jet nozzle during the soldering period of the printed wiring board by the above-described configuration, so that the solder rides on the upper surface of the printed wiring board at the start and end of the soldering. In the soldering of a printed wiring board which can be prevented and mounted at high density, the solder flow can be spread to each land portion and the soldering can be performed well.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings (FIGS. 1 to 3). In the drawings, the same reference numerals as those in the conventional example denote the same members, and a detailed description thereof will be omitted.

FIG. 1 shows a state in which a solder jet device according to an embodiment of the present invention passes through a printed wiring board. In FIG. 1, reference numeral 14 denotes a reflection type photo sensor,
Is detected, and the signal is sent to the solder jet level varying unit 15. The solder jet level variable section 15 has an automatic control function for controlling the output to the motor 4 and switching the output of the motor 4 for sending out the solder jet wave 6 from the solder jet nozzle 5 in two stages. Other configurations are the same as those of the conventional example.

Next, the operation of the solder jet device configured as described above will be described.

FIG. 2 shows the relationship between the transfer position of the printed wiring board 1 of this embodiment and the flow rate of the solder jetted from the solder jet nozzle 5, and as shown in FIG. When the front end passes through the detection position a of the reflective photosensor 14 and reaches the position b above the solder jet nozzle 5, the second end
As shown in FIG. 3B, the flow rate of the solder jetted from the solder jet nozzle 5 increases. The solder flow rate during the soldering period is maintained in an increased state, and the solder flow rate decreases at a position C slightly before the rear end of the printed wiring board 11 passes directly above the solder jet nozzle 5 [FIG. 2 (C)]. reference〕. FIG. 3 is a graph showing the increase and decrease of the solder flow rate in FIG. 2, and the reflection type photo sensor 14 detects the passage of the front end of the printed wiring board 1 (FIG. 3a).
Then, a communication signal is sent to the solder jet level varying unit 15, and a timer for increasing the rotation speed of the motor 4 is set. The point at which the rotation speed of the motor 4 is increased and the solder flow rate is increased (position b in FIG. 3) is a predetermined time after the reflection type photosensor 14 detects the passage of the front end of the printed wiring board 1, that is, the printing is performed. This is set immediately after the front end of the wiring board 1 passes directly above the solder jet nozzle 5 to prevent the solder from getting on the upper surface of the printed wiring board 1. Since the flow rate of the solder during the soldering period is maintained in an increased state, the soldering of each land of the printed wiring board 1 is improved. The point of time when the rotation speed of the motor 4 is reduced and the solder flow rate in the timer is reduced (position c in FIG. 3) is set slightly before the rear end of the printed wiring board 1 passes just above the solder jet nozzle 5 and printing is performed. At the rear end of the wiring board 1, the solder is prevented from running on the upper surface.

Advantageous Effects of the Invention As described above, according to the present invention, it is possible to prevent the solder from getting on the upper surface of the printed wiring board during soldering, and to improve the soldering to each land of the printed wiring board, and to perform the rework after soldering. The loss can be greatly reduced, and the reliability of the printed wiring board can be greatly improved.

[Brief description of the drawings]

1 to 3 show one embodiment of the present invention. FIG. 1 is a sectional view of a solder jet device, and FIGS. 2 (A) to 2 (C) show the relationship between the transfer position of a printed wiring board and the solder flow rate. FIG. 3 is an operation explanatory diagram for explaining the relationship, FIG. 3 is an explanatory diagram showing the increase and decrease of the solder flow rate in FIG. 2, FIG. 4 to FIG. 8 show a conventional example, and FIG. FIG. 5 is a perspective view of the main part, FIG. 6 is an enlarged cross-sectional view of the main part for explaining a soldering state of the high-density mounting printed wiring board, and FIG. 7 shows a state where the solder runs from the front end of the printed wiring board. FIG. 8 is an operation explanatory view showing a state where the solder runs from the rear end of the printed wiring board. 1 ... printed wiring board, 3 ... solder jet blade, 4 ... motor, 5 ... solder jet nozzle, 6 ... jet wave, 7 ...
Solder bath, 14 ... Reflective photo sensor, 15 ... Solder jet level variable section.

Claims (1)

(57) [Claims] 1. A solder tank for storing solder, a solder jet nozzle for guiding the solder in the solder tank in the direction of a printed wiring board passing through the upper portion of the solder tank, and a solder jet from the solder jet nozzle. A solder jet blade for sending the solder in the solder bath in the direction of the solder jet nozzle, and a solder jet for controlling the flow rate of the solder from the solder jet nozzle by changing the rotation speed of the solder jet blade in two stages. A level variable section, and a position detecting section for detecting a position of the printed wiring board, wherein the solder jet level variable section has a predetermined time after the position detecting section detects the passage of the front end of the printed wiring board. A timer for controlling the driving of the solder jet level variable section so as to increase the flow rate of the solder jetted from the solder jet nozzle and decrease the flow rate of the solder slightly before the rear end of the printed wiring board passes. Vignetting solder jet apparatus.