JPH02143489A - Printed-wiring board - Google Patents

Abstract

PURPOSE:To contrive the improvement of a working efficiency by a method wherein a solder masking reagent, which can be stripped away, is screen-printed on a printed-wiring board, on which a soldering is performed a plurality of times, dividing into every region where is soldered simultaneously at the times following at least the second time. CONSTITUTION:A thermosetting bonding agent 16 is applied between soldering regions for chip components 14 for fixing the components 14 on the surface on one side of a wiring board 10A by a first soldering. The components 14 are fixed on this bonding agent 16 and the electrode parts are made to position on the soldering regions of the board 10A. The components 14 are soldered by the first soldering. Then, a solder making reagent 12A covering a through hole 18 from a surface (a) is peeled by a tweezers or the like and with components 14A installed on the other surface of the board 10, a discrete component 20 is installed on the hole 18 in the board 10A from the surface (a) toward a surface (b). Moreover, the board 10A is turned inside out and the side of the surface (b) is soldered by a wave soldering method.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a printed wiring board used for mounting components by performing soldering work in two or more steps.

(Background of the Invention) In recent years, high-density packaging of printed wiring boards has progressed more and more, and, for example, it is known that IC parts, chip parts, etc. are mounted on both sides of a printed wiring board. In this case, a solder immersion method in which a printed board is immersed in a molten solder bath, a wave soldering method in which a raised flow is created on the surface of molten solder and the printed board is brought into contact with the raised portion, and the like are used.

In this case, during the first soldering, it is necessary to cover the area to be soldered from the second time onwards with a Tsurutar masking agent (Suruta resist).

FIG. 4 is a diagram showing a conventional soldering process. First, the printed wiring board 10 is delivered from the printed board manufacturer to the equipment assembly manufacturer without a solder mask (A), and the equipment assembly manufacturer leaves only the area to be soldered in the first soldering operation. The other soldering area (the area indicated by the arrow in FIG. 4(A)) is manually masked with solder masking agent 12 (B). This work is usually performed by applying the masking agent with a brush or brush. After the masking agent 12 dries, parts 14 such as ICs and chips are fixed with adhesive and further soldered using wave soldering method (C). When the first soldering is completed in this way, solder masking is performed. The area to be soldered a second time is exposed by peeling off the adhesive 12 with a bottle set or the like (C). Then, in the same way as the first soldering, the parts are glued together, immersed in a solder bath, and soldered to complete the mounting of the parts (D)
If soldering is carried out three or more times, the masking agent 12 may be peeled off each time.

As described above, in the past, masking was performed manually and the masking agent was removed from a large number of masked areas by hand, resulting in very poor work efficiency and poor productivity.

(Object of the Invention) The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a printed wiring board that is suitable for improving productivity by significantly improving the work efficiency of soldering when soldering is performed in multiple steps. The purpose is to provide.

(Structure of the Invention) According to the present invention, in a printed wiring board used for mounting components by multiple soldering operations, the soldering area where the soldering operations are simultaneously performed at least for the second time or later This is achieved by a printed wiring board characterized in that a removable solder masking agent is screen-printed separately for each soldering area where soldering work is simultaneously performed.

That is, the masking agent covering the area to be soldered at the same time is screen printed so that it can be removed in one operation.

(Embodiment) FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing a soldering procedure. The printed wiring board 10A of this embodiment is for double-sided mounting in which soldering is performed twice, and the area to be soldered the second time is covered with a solder masking agent 12A by screen printing. Here, the solder masking agent 12A is printed so as to connect each mask area and continue. As the solder mask agent 12A, an easily peelable material such as epoxy or acrylic thermosetting resin is used.

Components are soldered to both sides of this printed wiring board 10A as shown in FIG.

First, during the first soldering, one side of the wiring board 10A (
A thermosetting adhesive 16 is applied between the soldering areas of the chip components 14 in order to fix the chip components 14 on the surface A).
(A in the same figure), fix the chip component 14 to this adhesive 16, position the electrode part on the soldering area of the wiring board 10A (B in the same figure), and heat the adhesive 16 in an oven. After hardening (C in the same figure), the wiring board IO
Turn A upside down and perform the first soldering using wave soldering, etc. As a result, chip part 1
4 will be soldered (D in the same figure).

Next, remove the solder mask agent 12A covering the through hole 18 from side A with a bottle set or the like (E in the same figure), and bond the chip component 14A to the other side (side B) of the wiring board 10A. The discrete component 20 is installed in the 10A through-hole 18 from the 8th side to the 5th side (FIG. F). Then, the wiring board 10A may be turned over and the lower five surfaces may be soldered using the wave soldering method (Drawing G).

In the above embodiment, soldering is performed twice, and the solder masking agent 12A is printed as one continuous area, but in the present invention, the solder masking agent is printed in two or more areas. However, soldering may be performed two or more times.

Figure 3 shows the screen printing of the solder masking agent divided into four areas, and each area is numbered 1 in the order of the process.
~4 is attached. When soldering for the first time, remove the solder mask from the °° 1" area, and then
Peel off the 2°°~°°4” area and solder in order.

By masking the entire surface in this way, the effect of protecting the printed wiring board during transportation can also be obtained.

4゜(Effects of the Invention) As described above, the present invention provides a printed wiring board that is soldered multiple times, so that the soldering areas that are simultaneously soldered from the second time onwards are soldered at - degrees. Screen-printed removable solder masking agent in separate areas eliminates the need to manually apply solder masking agent with a brush or brush.
Just remove the solder mask in the order of soldering,
This has the effect of significantly improving work efficiency and productivity.

[Brief explanation of the drawing]

Fig. 1 shows an embodiment of the present invention, Fig. 2 shows its soldering procedure, Fig. 3 shows another embodiment, and Fig. 4 shows a conventional soldering process. It is. 10A...Printed wiring board. 12A--Sulter masking agent, 14.14A--Chip parts, 20--Discrete parts. Figure (C) Douzanku pattern 5 (Hi↓ (D)

Claims (1)

[Claims] On a printed wiring board used for mounting components by multiple soldering operations, for each soldering area where soldering operations are performed simultaneously for at least the second and subsequent soldering operations. A printed wiring board characterized by screen-printing a solder masking agent that can be separated and peeled off.