JPS5933940B2 - How to caulk lead pins - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lead pin caulking method that can ensure a good connection between the lead pin and a wiring metal layer of a substrate.

Conventionally, when caulking lead pins, through-hole plating was applied to the board's lead pin insertion hole, and a wire-shaped lead pin with no protruding parts was fixed to this insertion hole, thereby connecting the lead pin and the wiring metal layer via through-hole plating. Was.

However, through-hole plating has drawbacks such as a complicated process and high cost. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for caulking a lead pin, which is simple and inexpensive, and allows good connection between the lead pin and the wiring metal layer of a board to be obtained without using through-hole plating.

That is, the lead pin caulking method of the present invention includes a lead pin in which a first annular protrusion and a second annular protrusion having a diameter larger than the first annular protrusion are arranged side by side from the tip side at the rear end of the pin, and the lead pin is attached to an insulating base material and By driving the lead pin into the lead pin insertion hole of the board consisting of the wiring metal layer fixed thereon, the first annular protrusion having a diameter larger than the lead pin insertion hole rubs the wiring metal layer to generate heat, and then inserts into the insulating base. It is characterized in that the second annular protrusion bites into the material, and almost at the same time, the second annular protrusion comes into contact with the heated wiring metal layer to form an alloy between the two.

In this method, a lead pin of a special shape as shown in FIG. 1 is used.

The lead pin 1 has a first annular protrusion 2 and a second annular protrusion 3 arranged side by side in order from the tip side at the rear end thereof, and the second annular protrusion 3 has a larger diameter than the first annular protrusion 2 and has a diameter larger than that of the first annular protrusion 2. The annular protrusion 2 has a slightly larger diameter than the lead pin insertion hole of the board. The lead pin 1 is manufactured by inserting a straight wire 4 into a jig 5 and applying mechanical pressure to the protruding end 6 of the wire 4, as shown in FIG. By applying pressure, the wire 4 is pushed out into the annular recess 7 of the jig 5, and the first annular protrusion 2 is formed. At the same time, the protruding end 6 of the wire 4 deforms along the edge 8 of the jig 5 to form the second annular protruding part 3.
is formed. This lead pin is made of KOV material or TNF.
It is the material.

It is common to perform base plating and then tin plating before driving into the board. Also, the diameter of the first annular protrusion 2 of the lead pin 1 is approximately O, 6 mwL, the diameter of the second annular protrusion 3 is approximately O, 75 ml, and the diameter of the lead pin itself is approximately 0.4.
5 to 0.55 mm is common. Next, the lead pin is driven into the lead pin insertion hole of the board as shown in FIGS. 3 and 4. First, as shown in Fig. 3, insert the lead pin 1 into the lead pin insertion hole of the board until it reaches just before the first annular protrusion 2, and then approximately 5Kv/? The lead pin 1 is driven in with a certain degree of mechanical pressure using, for example, an air cylinder. On the other hand,
The substrate consists of an insulating base material 9, such as glass cloth epoxy, and a wiring metal layer 10 affixed thereon. This wiring metal layer 10 is formed into a desired circuit pattern by photo-etching, and a laminated metal foil 1 such as copper is layered from the bottom layer.
1, a base plating 12 such as nickel, and a surface plating 13 such as gold or silver. Of course, in this method, the lead pin insertion hole is not plated with through holes. When the lead pin 1 is driven in as described above, the first annular protrusion 2 first rubs against the wiring metal layer 10 and generates heat.

The first annular protrusion 2 further bites into the base material 9 to fix the lead pin 1. Since the second annular protrusion 3 has a larger diameter than the first annular protrusion 2, it is pressed against the wiring metal layer 10 which is heated as described above, and at the same time, alloying occurs due to the heat. This alloying is mainly performed between the tin plating of the lead pin 1 and the gold or silver plating 13 of the substrate. The surface plating 13 is generally made of gold or silver, and it has been confirmed that in this case, heat generation due to friction of the first annular protrusion 2 alone can sufficiently achieve alloying. In the case of silver, there may be some problems from a systematic standpoint, but it has been confirmed that silver contains some impurities and can be sufficiently alloyed. Furthermore,
In order to eliminate variations in alloying and obtain perfect conduction, it is preferable to heat the lead pin appropriately in advance. According to this method, good conductivity can be obtained between the lead pin and the wiring metal layer without having to perform through-hole plating on the lead pin insertion hole as in the conventional method.

Therefore, compared to the conventional method, the process is simple, efficient, and can be carried out at low cost.

[Brief explanation of drawings]

FIG. 1 is a front view of the lead pin used in this method,
FIG. 2 is a sectional view showing the manufacturing process of the lead pin shown in FIG. 1. FIGS. 3 and 4 are cross-sectional views showing the process of driving lead pins into the substrate. 1...Lead pin, 2...
...First annular protrusion, 3... Second annular protrusion, 9... Insulating base material, 10... Wiring metal layer.

Claims (1)

[Claims] 1 At the rear end of the pin, a first annular protrusion and the first
By driving a lead pin having a second annular protrusion with a diameter larger than that of the annular protrusion into a lead pin insertion hole of a substrate made of an insulating base material and a wiring metal layer fixed thereon, The first annular protrusion of the diameter rubs the wiring metal layer to generate heat, and then bites into the insulating base material, and almost at the same time, the second annular protrusion comes into contact with the heated wiring metal layer, causing a gap between the two. A lead pin caulking method characterized by alloying.