JPS59119896A - 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 Field of the Invention The present invention relates to a soldering apparatus, and more particularly to a jet soldering apparatus.

BACKGROUND TECHNOLOGY AND PROBLEMS Conventionally, jet soldering equipment has been used to solder chip components, and the printed circuit board on which chip components are mounted is placed at right angles to the longitudinal direction of the solder jet opening, that is, in the direction of the solder jet. The soldering process was carried out by moving the parts in the same straight line as the parts.

FIG. 1 is a schematic diagram showing the situation, with FIG. 1A being a plan view and FIG. 1B being a side view. In the figure, (1) is a printed circuit board, (2) is a solder jet port, (two are solder jets, and the arrows indicate the direction of movement of the board (1) and the solder jet direction.However, such conventional When soldering chip parts, soldering is usually done without making a hole in the land part (soldering part), so the soldering is mainly done by vaporizing flux and producing gas (some air may also be included). .

) escapes <<, and as a result, soldering defects occur due to solder not adhering (solder does not adhere), especially on the rear side of the chip component (the part that is shaded on the rear side from the solder jet). It had some drawbacks. FIG. 2 is a sectional view showing a pattern in which generated gas accumulates, and parts corresponding to those in FIG. 1 are given the same reference numerals. In the figure, (3) is a chip component, (4
) shows the gas generated on the rear side of the chip component (3).

As a countermeasure against soldering failures as described above, for example, a method of drilling holes in the printed circuit board as disclosed in Japanese Patent Publication No. 55-38077 has been considered, but this method requires extra space for drilling holes in the printed circuit board. This has the disadvantage that it is not suitable for high-density packaging.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a soldering device that does not have the above-mentioned drawbacks and can reliably solder chip components.

Summary of the Invention The present invention achieves the above object by making the direction of the solder jet in the solder bath inclined with respect to the direction of movement of the printed circuit board, and by providing a difference in height between the two board transport rails. be.

Embodiment FIG. 3 is a schematic diagram showing an inclined solder jet port used in the present invention. (2 “); The direction of the solder jet is set to the printed circuit board (1
) shows an inclined solder jet opening tilted by θ1 with respect to the direction of travel. In this case, the angle between the longitudinal direction of the solder jet port (2") and a line perpendicular to the direction of movement of the printed circuit board (1) is also θ1
Therefore, this angle is shown in the figure for convenience.

The inventors of the present invention have discovered that if the solder jet port is inclined to a certain degree in this manner, the above gas can be easily removed. This is because if the solder jet is slanted, it is difficult for the jet solder to adhere to the corner edges of the electrodes of the chip component. This is thought to be because since it hits the component obliquely, force is applied to the gas in the direction along the outer surface of the chip component, making it easier for the gas to escape along the outer surface of the chip component (see FIG. 8).

FIG. 4 is a characteristic diagram showing the effect of the inclined solder jet. In the figure, the inclination angle θ1-00 indicates the case using the conventional method as shown in Figure 1, and the ○ and Δ marks indicate the failure of solder for two types of printed circuit boards when θ1=00 and θ1=5°. This is experimental data.

From this figure, it can be seen that when the angle is 01-5 degrees, the defective rate due to solder aging is significantly reduced compared to when θl is 200 degrees. It was also observed that a similar effect was obtained in the range of θl = 3 to 45°, but if the surplus θ1 is increased, the length in the longitudinal direction of the solder jet port must also be increased, so in practice, θl = A suitable angle is 5 to 15 degrees.

However, by tilting it, the number of defects due to solder defects decreased, but the number of bridge defects due to poor separation between parts and solder increased. In Figure 4, the X marks are 01=08 and 01
Experimental data of bridging failure at −5° is shown. Therefore, in the present invention, by using an inclined solder jet port and providing a difference in height between the two board conveying rails, it has been possible to reduce the number of solder defects and bridge defects.

5 to 7 show an embodiment of the present invention, in which FIG. 5 is a plan view, FIG. 6 is a side view, and FIG. 7 is a front view.

FIG. 8 is an explanatory diagram showing the relationship between chip components and inclined solder jets. In the figure, (5) indicates a solder tank, (6) a motor, and (7) a board conveyance rail (or chain). The example shown in FIG. 5 is a case where the solder jet port (2'') is inclined in the opposite direction to that shown in FIG. 72) Compose.

It is well known that in soldering by jet soldering, if the printed circuit board (1) is advanced up an incline, the amount of adhered solder is kept to the minimum necessary and the occurrence of bridge failures is reduced. Therefore, in this embodiment, two rails (7
s) -(7*) was tilted upward by θ2 in the horizontal direction with respect to the traveling direction of the substrate.

At the same time, as shown in FIG. 7, two rails (71).

(72) has two rails (7r) with a difference in height, (
72) so that the angle formed between the straight line connecting them and the horizontal direction is 03.

In this way, the printed circuit board (1) is advanced up the slope and pulled up obliquely9, thereby making it possible to extremely reduce bridging defects. Although not shown, these angles θ2. It is possible to configure it so that θ3 can be adjusted appropriately. Since such a configuration can be easily designed by a person skilled in the art, its explanation will be omitted. Note that θ2=
It may be set to 0.

Figure 8 shows chip parts (3), (3), etc. in each direction.
・The flow along its four sides (4 sides) prevents the gas generated behind the parts from accumulating and ensures wetting by the solder. In addition, the inclination angle θ of the solder jet port (2")
1 will also be configured as a town so that it can be adjusted.

Having described the invention in detail, according to the present invention, it is possible to reduce defects caused by soldering that are peculiar to chip components without impairing the high-density mounting of printed circuit boards, and it is also possible to significantly reduce bridge defects. , it is possible to reliably solder chip components.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the conventional soldering method, Figure 2 is a diagram showing the method of conventional soldering.
A cross-sectional view showing gas generation when chip components are soldered by the method shown in the figure, FIG. 3 is a schematic diagram showing the inclined solder jet method used in the present invention, and FIG. 4 shows the effect of the method shown in FIG. 5 to 7 are diagrams showing embodiments of the present invention, FIG. 5 is a plan view thereof, FIG. 6 is a side view thereof, FIG. 7 is a front view thereof, and FIG. 8 is a chip component. FIG. 3 is an explanatory diagram showing the relationship between the solder jet flow and the inclined solder jet flow.

Claims (1)

[Claims] In addition to tilting the direction of the solder jet in the solder tank with respect to the traveling direction of the printed circuit board, the two rails that transport the printed circuit board are also provided with a height difference, so that defects caused by aging of solder and bridge defects can both be reduced. The soldering is done using a device.