JP3232668B2 - Manufacturing method of printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board.

[0002]

2. Description of the Related Art FIG. 2A is a plan view showing a state in which a conventional printed wiring board is mounted on a metal part, and FIG. 2B is a plan view of FIG.
It is sectional drawing which follows the DD line. In the figure, reference numeral 21 denotes a substrate main body, and a screw insertion hole 22 is provided at an end of the substrate main body 21. Patterns 23 for forming a solder film are provided on the mounting surface of the board body 21 at predetermined intervals in the longitudinal direction of the board body 21, and these patterns 23 are related to the distance from the screw insertion hole 2. And all have the same shape.

[0003] Cream solder is applied to the above pattern 23 in a uniform thickness before reflow is performed, and a solder film 24 is formed by performing reflow. At this time, the thickness of the solder film 24 is the same because the patterns 3 have the same shape.

[0004] The printed wiring board B constructed as described above is fixed to the metal part 26 by the fixing screw 25 inserted through the screw insertion hole 22, and the printed wiring board B and the metal part 26 are fixed.
Can maintain electrical contact as well as mechanical contact when fixed by the solder film 24.

[0005]

However, in the above-mentioned conventional printed wiring board B, when the fixing screw 25 is tightened, the solder film 24 on the pattern 23 of the short distance portion 27 which is short from the screw insertion hole 22 is compressed. Since the solder film 24 on the pattern 23 of the long distance portion 29 which is deformed and is far from the screw insertion hole 22 is not compressed and deformed, the printed wiring board B is moved between the short distance portion 27 and the middle distance portion 28. There is a problem in that the printed wiring board B and the metal part 26 do not come into contact with each other due to warpage and deformation, and a gap is formed between the solder film 24 and the metal part 26 in the long distance part 29.

An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a printed wiring board which can be fixed to a metal part in a high contact state.

[0007]

In order to achieve the above object, a pudding joined to a metal part provided in a housing by a fixing tool.
On the wiring board far from the position where the fixture is installed
The area of the pattern that forms the solder film
Resize the printed circuit board,
The height of the solder film formed on the pattern is
Form sequentially higher from a near position to a far position
A method of manufacturing a printed wiring board characterized by the following.

[0008]

With this configuration, by changing the thickness of the solder film depending on the location, the contact between the printed wiring board and the metal part is enhanced, and the printed wiring board and the metal part are electrically and mechanically highly contacted. Has the effect that they can be fixed to each other while maintaining the same.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a plan view showing a state in which a printed wiring board according to the present invention is mounted on a metal part, and FIG.
(A) It is sectional drawing which follows CC line. In the figure, reference numeral 1 denotes a substrate main body, and a screw insertion hole 2 is provided at an end of the substrate main body 1. Patterns 3 for forming a solder film are provided on the mounting surface of the board main body 1 at predetermined intervals in the longitudinal direction of the board main body 1.
The length is different depending on the distance from.

That is, the length of the pattern 3-1 of the short distance portion 5 which is short from the screw insertion hole 2 is the longest, the length of the pattern 3-2 of the middle distance portion 6 is medium, and The length of the pattern 3-3 of the distance portion 7 is small. Even in the pattern 3-2 of the middle distance portion 6, the distance from the screw insertion hole 2 is small as the distance from the screw insertion hole 2 is far, and also in the pattern 3-3 of the long distance portion 7 from the screw insertion hole 2. The longer the distance, the shorter the length.

[0011] Cream solder is applied to the above-mentioned patterns 3-1, 3-2 and 3-3 in a uniform thickness before reflow, and a solder film 8 is formed by reflow.
At this time, the solder film 8 is applied to the patterns 3-1, 3-2, 3-3.
Its thickness is controlled by the shape of the.

That is, the length of the pattern 3-1 of the short distance portion 5 which is short from the screw insertion hole 2 is the longest, the length of the pattern 3-2 of the middle distance portion 6 is medium, and for the length of the pattern 3-3 of the distance portion 7 is small, one
When a constant amount of solder is reflowed on each pattern, the thickness of the solder film 8 increases as the distance from the screw insertion hole 2 increases.

The printed wiring board A thus constructed is fixed to the metal part 10 by the fixing screws 9 inserted into the screw insertion holes 2. In this case, when the fixing screw 9 is tightened, the solder film 8 on the pattern 3-1 of the short distance portion 5 where the distance from the screw insertion hole 2 is short is deformed by compression, and the distance from the screw insertion hole 2 is long. Since the solder film 8 on the pattern 3-3 of the portion 7 is not compressed and deformed, the printed wiring board A warps between the short distance portion 5 and the middle distance portion 6, but as described above, Since the thickness of the solder film 8 is increased as the distance from the hole 2 increases, the printed wiring board A does not warp, and a gap is generated between the printed wiring board A and the metal part 10. Nothing.

As described above, according to the above embodiment, since the printed wiring board A and the metal part 10 can be fixed to each other without generating a gap, the printed wiring board A and the metal part 10 can be electrically and mechanically connected. There is an advantage that it can be fixed stably.

[0015]

According to the present invention, the thickness of the solder film formed on this pattern is controlled by changing the shape of the pattern for forming the solder film on the substrate body, as is apparent from the above embodiment. By changing the thickness of the solder film depending on the location, the contact between the printed wiring board and the metal part is enhanced, and the printed wiring board and the metal part are fixed to each other while maintaining high electrical and mechanical contact. It has the effect of being able to.

[Brief description of the drawings]

FIG. 1A is a plan view of a state in which a printed wiring board according to the present invention is mounted on a metal part. FIG. 1B is a cross-sectional view taken along line CC of FIG.

FIG. 2 (a) is a plan view showing a state where a conventional printed wiring board is attached to a metal part, and FIG. 2 (b) is a sectional view taken along line (a) DD.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Board main body 3 Pattern 8 Solder film 10 Metal part A Printed wiring board

Claims (1)

(57) [Claims] 1. A metal part provided on a housing is joined by a fixing tool.
Location on the printed circuit board where the fixture is installed
The surface of the pattern on which the solder film is to be formed
The product is sequentially reduced, and the printed wiring board is reflowed.
The height of the solder film formed on the pattern,
Form sequentially higher from a position closer to the fixture to a position farther away
A method for manufacturing a printed wiring board.