JPS59194491A - Soldering method using mask - 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 method of soldering electrical components to printed wiring boards.

Background technology and its problems When soldering both electrical components with lead wires and chip components to a printed wiring board that uses electrical components with lead wires, such as phenol, glass cloth, paper epoxy, etc.
In order to achieve high-density mounting, as shown in Figure 1, electrical components with lead wires are mounted on the surface on which the components are to be mounted (component surface), and chip components are mounted on the putter surface 7 on the opposite side. It is a good idea to use a hybrid mounting method. In Figure 1, (1) is a printed wiring board, (1)
1) is the part side, (12) is the 7th side of the putter, (2)
s is an electric component with a lead wire, (2i) is the lead wire, (3) is the chip component, and (4) is the attached solder.

However, in such a hybrid mounting method, if the lead wire is cut after both the lead wired component and the chip component are soldered, there is a drawback that the lead wire cannot be cut shorter than the thickness of the chip component. Therefore,
In order to overcome this drawback, a method that can be considered is to first solder the components with lead wires, cut the lead wires, and then solder the chip components (double dip method), but When soldering (dipping) in a bath, solder adheres to the lands (soldering points) of chip components and swells, causing variations in the amount of solder swell. If there is a place with a large amount of solder buildup, it may become impossible to mount the chip component (misalignment of the mounting position, damage), or a gap may occur between the land copper foil surface and the chip component, causing soldering failure. , various problems occur.

OBJECTS OF THE INVENTION It is an object of the present invention to overcome the drawbacks of hybrid mounting systems as described above.

SUMMARY OF THE INVENTION The present invention shields the chip component land on the printed wiring board pattern surface with a mask material before inserting an electrical component with lead wires from the component side of the printed wiring board, and attaches the lead wired components in a solder bath. The above objective was achieved by performing soldering, cutting the lead wires before or after removing the mask material, and then mounting the chip component and soldering the patterned surface.

Example FIG. 2 is a process diagram showing an embodiment of the present invention.

In the figure, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and explanations thereof will be omitted. FIG. 2A is a diagram showing the first step, with the upper diagram being a sectional view and the lower diagram being a bottom view. Prior to soldering, place the masking sheet (5) on the pattern side (12
) by an appropriate means. For example, attach adhesive to both ends of the masking sheet (5) and select which one is the substrate (
1) Paste it on. The masking sheet (5) has holes (through which the lead wires (21) of the component (2) with lead wires are inserted).
A large number of holes (51) are made to expose the lands (14) formed around the side ports of the patterned surface (12) of 13). In the figure, only a portion of the masking sheet (5) is shown. The material of the masking sheet (5) is:
Any material may be used as long as it prevents solder from adhering and can withstand the heat of soldering. Masking sheets (5
), it is necessary that this adhesive also has similar heat resistance. The masking sheet (5) covers the parts other than the component lands with lead wires (14) that will be bonded during the first soldering (the lands of chip components and the insertion holes of components for retrofits such as switches, volume controls, jacks, etc.). .) has the role of shielding. After completing the mask, the component with lead wires (2) is inserted into the hole (13) and mounted. FIG. 2B is a sectional view showing this state. Next, after soldering this in a solder bath, the lead wire (21) is cut short to a desired length by hand or machine, before or after removing the masking sheet (5). FIG. 2C is a side view showing the cut state after the masking sheet (5) has been removed. If the cut is made before removing the masking sheet (5),
After peeling off the masking sheet (5) and applying temporary adhesive, the chip component (3) is mounted and soldered using a solder bath. The second diagram is a side view showing the state after completing two dips.

In the above embodiment, a masking sheet was used as the masking material, but a masking agent may be used instead.

Effect of the invention The present invention has the following various remarkable effects.

(b) The lead wires of components with lead wires can be cut shorter than the thickness of the chip component, and therefore the space in the height direction on the chip component mounting surface can be minimized, making the product thinner. It can be measured.

(b) Even if the primary soldering of components with lead wires passes through the process, due to the masking effect, the copper foil to be soldered to the chip component land remains clean, so the mounting and soldering of chip components is stable. become That is, mounting and soldering of chip components will not become impossible, and soldering defects will not occur.

(c) The soldering that occurs when cutting the lead wires of parts with lead wires is subject to deterioration due to mechanical and thermal stress in the parts.
Soldering in a soldering tank a second time improves reliability.

(d) High-density mounting using the hybrid mounting method can be achieved without any problems.

[Brief explanation of drawings]

FIG. 1 is a side view showing a hybrid mounting system, and FIG. 2 is a process diagram showing an embodiment of the present invention. (1)...Printed wiring board, (2)...
Electrical parts with lead wires, (3)...Chip parts,
(4)・・・Solder, (5)・・・Mask.

Claims (1)

[Claims] A step of shielding the chip component land on the printed wiring board with a mask, a step of inserting and soldering the electrical component with lead wires, and a step of shielding the electrical component with lead wires before or after removing the mask. A method of soldering using a mask, which comprises the steps of cutting lead wires and temporarily fixing chip components before soldering.