JPH057073A - Spare soldering method onto printed-substrate - Google Patents

Abstract

PURPOSE:To increase the working efficiency in relation to the title spare soldering method onto printed substrate. CONSTITUTION:Spare solders 3 are screen-printed on a solder feeding board 4 comprising Pyrex glass corresponding to the pad positions 2 arranged on a printed-substrate 1 and then the solder feeding board 4 is pressure-fixed on the printed-substrate 1 to be fixed using a magnet 13, a mask 15 and a weight 14. Next, the spare solders 3 on the solder feeding board 4 are made to reflow so that they 3 may be fed to the pads 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for pre-soldering a printed circuit board.

[0002]

2. Description of the Related Art Conventionally, preliminary soldering of a printed circuit board is performed by the procedure shown in FIG. That is, after applying a flux (not shown) to the pad 2 provided on the printed circuit board 1, the solder 7 previously sucked into the solder wick 6 by the soldering iron 5 is melted and supplied onto the pad 2. Then, as shown in FIG.
The solder wick 6 absorbs the solder 7 on the pad 2 to leave a solder having a thickness of about several μm on the pad 2, and the preliminary soldering is completed.

[0003]

However, in the above-mentioned conventional example, since the pad 2 is rubbed by the solder wick 6, the pad 2 is scratched or the solder wick is not melted. 6 may be pulled to peel off the pad 2, and the same troublesome work needs to be performed on all the pads 2, 2, ... On the printed circuit board 1, resulting in poor work efficiency. It was something that had.

In addition, when the solder wick 6 is used to attach the auxiliary solder 3, the amount of solder supplied to the pad 2 varies greatly. Therefore, when the solder wick 6 is excessively supplied, the solder 7 needs to be sucked up. As shown in FIG. 5, when excess solder on the pad 2 having the dents 8 on the printed circuit board 1 is absorbed and then electronic parts are bonded to the pads 2, the flux entering the dents 8 during the reflow process may be disturbed. In addition, there is a drawback that bubbles called voids are generated inside the solder at the joint, and the connection reliability is reduced.

In FIG. 5, 9 is a via for connecting the pad 2 to an inner layer, 10 is a collective conductor layer formed in a thin film on the surface layer of the substrate, 11 is a polyimide insulating layer, and the dent 8 is a collective conductor layer 10. This occurs because the pad 2 is formed on the polyimide insulating layer 11 having irregularities in order to obtain the electrical continuity.

The present invention has been made to solve the above drawbacks, and provides a preliminary soldering method for a printed circuit board, which has good working efficiency and does not cause peeling of pads or the like. With the goal.

[0007]

According to the present invention, the above object corresponds to the embodiment, and as shown in the embodiment, the spare solder 3 is made of Pyrex glass so as to correspond to the position of the pad 2 arranged on the printed circuit board 1. Screen printing is performed on the solder supply plate 4, and then the solder supply plate 4 is pressed onto the printed circuit board 1 to fix the solder supply plate 4 with the magnet 13, the mask 15 and the weight 14, and then the solder supply plate 4 is supplied. This is accomplished by reflowing the pre-solder 3 on the board 4 to provide a pre-soldering method on a printed circuit board that supplies the pre-solder 3 on the pad 2.

[0008]

In the present invention, the preliminary solder 3 is first screen-printed on the solder supply plate 4, and this is printed on the printed circuit board 1.
By transferring to the upper pad 2, the preliminary solder 3 is supplied.

As a result, the pad 2 is not rubbed, the peeling of the pad 2 is completely prevented, and the workability is improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 2 shows a solder supply plate 4 used in the present invention, which is formed by supplying a preliminary solder 3 on a transparent Pyrex glass. In addition, in this embodiment, the solder supply plate 4 is formed corresponding to each element mounted on the printed circuit board 1, but in addition to this, it is made to correspond to an area where two to three elements are mounted. It is also possible to form.

Solder supply to the solder supply plate 4 is performed by screen-printing a solder paste on the solder supply plate 4, and each solder paste is arranged corresponding to the position of the pad 2 on the printed board 1. It Further, a through hole 12 is provided in the center of the solder supply plate 4.

After the preliminary solder 3 is supplied to the solder supply plate 4 as described above, the preliminary solder 3 is dried on the solder supply plate 4, and then, as shown in FIG. The solder supply plate 4 is put on the printed circuit board 1 with the supply surface of the printed circuit board facing the pad 2 on the printed circuit board 1.
The setting of the solder supply plate 4 is performed by using a microscope arranged above the printed circuit board 1 while confirming that the respective preliminary solders 3 and the pads 2 on the printed circuit board 1 are correctly associated with each other.

After that, the printed board 1 is attached to the magnet jig 1.
3 and then the weight 1 on the solder supply plate 4.
4 is mounted (see FIG. 1B). Reference numeral 15 denotes a mask having an insertion hole 16 formed in a portion corresponding to the weight 14, which is made of a material such as stainless steel that is attracted by a magnet. The insertion hole 16 of the mask 15 is formed to be slightly smaller than the solder supply plate 4 so that the supply plate can be pressed from above with the mask 15 set.

When the printed circuit board 1 having the solder supply plate 4 set on the upper surface is sent to the reflow furnace as described above, the preliminary solder 3 on the solder supply plate 4 is melted and the printed circuit board 1 is melted.
The spare solder 3 is evenly supplied to the pad 2 of FIG. At this time, since each solder supply plate 4 is pressed from above by the mask 15 which is attracted by the magnet jig 13 arranged below the printed circuit board 1 as shown by the arrow in the figure, the preliminary solder 3 is Lateral displacement due to melting is reliably prevented, and solder is supplied to the predetermined pad 2 position.

Next, the printed circuit board 1 is removed from the magnet jig 13, the weight 14 and the mask 15 are removed, and then the solder supply plate 4 is removed to complete the preliminary solder 3 attaching work. When the solder supply plate 4 is removed, the solder supply plate 4 is adhered to the printed circuit board 1 due to the flux in the solder paste, and the pad 2 may peel off if it is forcibly peeled off. It is carried out while being immersed in the cleaning liquid, or spraying the cleaning liquid to melt the flux with the cleaning liquid.

In this case, since the cleaning liquid enters the interface with the printed circuit board 1 not only through the side edge portion of the solder supply plate 4 but also through the through hole 12 in the central portion, the work of separating the supply plate can be easily performed. it can.

In the above description, the case where the solder supply plate 4 is pressed by the weight 14 has been shown, but in addition to this, as shown in FIG. 3, the solder plate 4 is pressed by the pressing plate 18 which is urged downward by the spring 17. It is also possible to hold down the supply plate 4, and in this case, the lateral displacement of the solder supply plate 4 does not occur, so that the magnet jig 13 is not necessary.

[0018]

As is apparent from the above description, according to the present invention, the preliminary soldering can be surely performed without using the solder wick, so that the working efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a view showing a solder supply plate, (a) is a plan view,
(B) is a side view.

FIG. 3 is a diagram showing a modified example of the present invention.

FIG. 4 is a diagram showing a conventional example.

FIG. 5 is a diagram showing a problem of a conventional example.

[Explanation of symbols]

 1 Printed circuit board 2 Pad 3 Spare solder 4 Solder supply plate

Claims (1)

Claim: What is claimed is: 1. A preliminary solder (3) is screen-printed on a solder supply plate (4) made of Pyrex glass so as to correspond to a position of a pad (2) arranged on a printed circuit board (1). After that, the solder supply plate (4) is crimped onto the printed circuit board (1) to fix the solder supply plate (4) with the magnet (13), the mask and the weight (14), and then the solder supply plate (4) is attached. A method of pre-soldering a printed circuit board, wherein the pre-solder (3) on the board (4) is reflowed to supply the pre-solder (3) on the pad (2).