JPS5933897A - Soldering device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for soldering a substrate such as a printed wiring board by spraying molten solder thereon.

Conventionally, in order to solder a printed circuit board, a dipping method was used in which the printed circuit board (4) was immersed in a molten solder bath (1) as shown in FIG. 10, or molten solder was applied in a bath (1) as shown in FIG. A flow method has been implemented in which the printed circuit board (4) is transferred while being jetted.

However, in the dipping method, the molten solder (51) and the substrate (
4) (This has the disadvantage that bubbles (6) are likely to be generated by gas or air generated from the board or flux, and that soldering to the conductor of the board in this area may be defective.

Also, the flow method is half F11. The purpose of the flow (5) is to expel the bubbles to the outside, or because the flow (5) is blown perpendicularly to the substrate (4),
The air bubbles (6) are pressed against the substrate by the buoyant force 1 and are difficult to escape to the outside. In particular, if resistors (7) such as chip components against the solder flow protrude from the board, a sufficient effect of removing bubbles cannot be obtained from the portions surrounded by these resistors.

Furthermore, in the flow method, at the part (P) where the solder flow (5) separates from the board (4), the angle (α) formed between the solder flow and the board becomes large, and unnecessary solder remains on the board due to surface tension, causing the bridge to deteriorate. It may be the cause.

The purpose of the present invention is to prevent air bubbles from accumulating between the solder flow and the printed circuit board. , a spray nozzle pipe (3) disposed on the guide plate (2) to spray the molten half 111 upward and in a band shape, and a guide device (8) for guiding the printed circuit board in parallel along the guide plate. Since the printed circuit board is always parallel to the solder flow and at an angle to the horizontal plane, air bubbles attached to the back side of the board rise along the back side of the board due to their own buoyancy and escape to the outside.

Furthermore, the solder flow always flows parallel to the substrate, and excess solder is removed by the force of the solder flow that is sufficiently greater than the surface tension of the solder, so that no bridge is formed.

The present invention will be specifically described below based on embodiments shown in the drawings.

For soldering, the device is a flat guide plate (
2) is placed diagonally with its lower end immersed in the tank (1), and a molten solder injection nozzle pipe (3) is placed along the guide plate (2) on the molten solder surface side on the guide plate (2). It is composed of

On the guide plate (2) there is a parallel rail (8n f81.) and a hanger +82) (82) having a claw portion f83) L83+ that slidably engages with the rail f81) and supports the printed circuit board (4). ) is arranged parallel to the guide plate (2).

As shown in FIG. 3, the nozzle pipe (3) has a nozzle opening (30) formed on the negative side of a square or round pipe with both ends closed.

Nozzle o f30) has multiple injection holes! 3]) [31
) are opened at a close pitch in the direction of the tube axis, and the diameter of the small holes gradually increases from one end to the other.

A molten solder supply pipe (33) is connected to the injection nozzle pipe (3), and a pump (not shown) provided in the molten solder tank (1) is connected to the pipe (33).

The injection nozzle pipe (3) is arranged on the guide plate (2) at a slight angle so that one end of the injection hole (31) with a larger diameter is higher than the other end.

The guide plate (2) has a built-in heater (not shown).
This prevents the molten solder sprayed from the nozzle (3) onto the plate (2) from cooling.

Thus, molten solder is sprayed from the nozzle pipe (3), and the printed circuit board (4) is moved laterally along the guide plate (2) and brought into contact with the solder flow (5).

Since the nozzle pipe (3) is arranged with a slight inclination, and the diameter of the higher end injection hole (31) gradually increases, the outflow resistance of the higher end injection hole (31) is small. Since the injection flow rate increases, the molten solder becomes a jet that draws a parabolic arc and flows through the guide plate [2+ + knee.

The printed circuit board (4) is exposed to the second solder flow during the transition.
As shown in the figure, the guide plate (2
), the printed circuit board (
The air bubble (6) generated between the solder flow (5) and the solder flow (5) rises due to its own buoyancy and escapes from one end of the printed circuit board (4).

In addition, the solder flow always flows in parallel to the printed circuit board, and the momentum of the solder flow is sufficiently greater than the surface tension of the solder, and excess solder is removed, leaving solder in unnecessary areas to form bridges. Never.

Further considering the movement of the solder flow against the horizontally moving printed circuit board (4), when the printed circuit board (4) first comes into contact with the solder flow, as shown in Figure 5, the solder flow (5) flows upward.
), in the middle part it comes in contact with a solder flow (5a) flowing sideways as shown in FIG.

That is, while the printed circuit board (4) passes through the solder flow, the jet flow of the jet amount 111 against the printed circuit board (4) is 1.
ζ→structure→t (this direction changes gradually).As a result, even if there is a resistor against the half-11-1 flow, such as a chip component arranged in a complicated manner on the printed circuit board (4), the half-Ll flow will not be affected. There are no blind spots and there is no risk of defects.

FIG. 4 shows another embodiment of the nozzle IZI (3o), in which a slit (32) whose width gradually narrows from one end to the other is provided on the -1-plane of the nozzle pipe (3). I](
30).

Since the nozzle pipe (3) described in -1- also has an increased jet flow on the wide side of the slit, molten solder can be sprayed in a semicircular shape by tilting the middle nozzle pipe (3) as described above.

FIGS. 8 and 9 show other embodiments, and FIG. 8 is a combination of the apparatus shown in FIG. 1 and an auxiliary injection nozzle pipe (34) that injects molten solder downward.

FIG. 9 shows an example using a spray nozzle pipe (3a) that can spray a solder-like jet to the left and right.

The nozzle pipe (3a) is formed slightly high in the center and has a plurality of small injection holes (31) formed at a dense pitch on the upper surface, and the small injection holes become larger toward the center of the nozzle pipe (3a). The diameter hole is gradually expanding.

In addition, the nozzle pipe (3a) in Fig. 9 has a plurality of jets.Instead of one small hole, a slit is provided along almost the entire length of the pipe, and the width of the slit gradually increases from both ends toward the center. It is also possible to implement

In addition, in the present invention, the nozzle pipe (3) has a large rise in the height of the jet flowing around the outer periphery of the arcuate solder flow that draws a parabola on the inclined surface of the guide plate (2), and the amount of the jet increases. (Of course, if the nozzle opening is modified, it is not limited to the illustrated example.

As described above, the present invention can spray molten solder along the inclined guide plate (2), so by moving the printed circuit board (4) along the guide plate (2), the flow can be reduced by The printed circuit board (4) is in parallel contact, and the air bubbles generated between the printed circuit board and the half line are connected to the printed circuit board (4).
along the back side of the printed circuit board (
4) There is no risk of the solder remaining on the back side and causing a solder failure.

Further, since the solder flow flows parallel to the substrate, the excess half [] is removed by the momentum of the solder flow that is sufficiently greater than the surface tension of the solder, and there are excellent effects such as no bridges being formed.

[Brief explanation of the drawing]

Figure 1 is an oblique view of the soldering device, Figure 2 is a side view of the printed circuit board in contact with the solder jet on the guide plate, and Figure 3 is a side view of the printed circuit board in contact with the soldering jet.
4 is a perspective view of another embodiment of the nozzle tube, FIGS. 5, 6, and 7 are explanatory diagrams showing the moving state of the printed circuit board, FIG. 9 is a front view of another embodiment, and FIGS. 10 and 11 are sectional views of the conventional example. (2)...Guide plate (3)...
Nozzle pipe (30)...Nozzle tube

Claims (1)

[Claims] ■ A guide plate (2) arranged obliquely on the molten solder bath (1), and a nozzle opening (30) arranged in the direction of the tube axis formed on the guide plate (2N-). a molten solder injection nozzle pipe (3) that injects molten solder upward and in a band shape from the nozzle opening (30) along the guide plate (2);
2) A board to be soldered, such as a printed circuit board, is placed parallel to the guide plate (2) on the guide plate (2), and the board to be soldered is supported.
2) A soldering device consisting of a guiding device (8) that guides along the soldering device. ■ The nozzle opening (30) is formed by a plurality of injection holes (31) arranged side by side in the tube axis direction, and the diameter of the small holes (31) gradually increases from one end to the other end. A soldering device according to claim 1. (2) The nozzle opening (30) is formed in a slit shape, and the slit width of the slit-shaped nozzle opening gradually increases from one end side to the other end side. Device. ■ The nozzle opening (30) is formed by arranging a plurality of small injection holes in parallel in the tube axis direction, and the small holes gradually increase in diameter from both ends toward the center. The soldering described is a device. (2) The soldering device according to claim 1, wherein the nozzle opening (30) is formed in the shape of a slit, and the slit width of the slit-shaped nozzle opening gradually increases from both ends toward the center.