JPH01232703A - Manufacture of electronic parts - Google Patents

Abstract

PURPOSE:To equally form the length of tips of lead wires protruding from the rear side of a printed board by a method wherein, after resin has been coated, the mounting resin is hardened, the excision of the tip part of the dripped resin of the base part of the lead wire and the cutting of the tip part are conducted simultaneously by making equal the intervals between the excited parts and also between the cut parts. CONSTITUTION:After a thermosetting process has been completed, the resin at the base part of lead wires 2 becomes resin 3B by the setting. Said lead wires 2 are fitted to the part between the fixed part 10A and the moving part 10B of a cutting tool 10, the moving part 10B is shifted, and the cutting operation of the dripped resin 3B' and the lead wire 2 are conducted. The fixed part 10A and the moving part 10B have a fine blade-shaped projection on the part surrounding the lead wires 2. Cut parts 11 having certain lengths in the longitudinal direction are provided. At the same time, a cutting blade 12 is provided on the part surrounding the tip parts of the lead wires 2, said tip parts are cut, the dripped resin 3B' is broken by the edge of the blade, and an electronic part is pulled out upward. As a result, the exposed length of the lead wires 2 from the tip of the dripped resin 3B to the tip of the lead wires 2 exactly becomes the value of the H determined by the cutting tool 10.

Description

[Detailed Description of the Invention] [Industrial Application Field] Many electronic components such as film capacitors are coated with dip coating. The present invention relates to a method for manufacturing a resin-clad electronic component using such a dip coating method, and particularly to cutting lead wires of an electronic component having a plurality of terminal lead wires.

[Conventional technology]

When mounting a resin-clad electronic component using the dip coating method on a printed circuit board that has multiple terminal lead wires running parallel to each other on the same side of the main body, insert the lead wires into the through holes in the land of the Print+-X board. It is common to solder.

In dip-exposed electronic components, there is always dripping resin at the base of the lead wire, and the shoulder of this dripping resin supports the electronic component on the front side of the printed circuit board, with the tip of the lead wire protruding from the back side of the printed circuit board.

If the protruding length from the back side of the printed circuit board varies for each lead wire, it will cause problems in soldering work and subsequent handling of the mounted printed circuit board. For this reason,
Users are placing strict demands on electronic component manufacturers regarding lead wire length.

[Problem to be solved by the invention]

As a countermeasure to the above, a method known in Japanese Patent Publication No. 61-22442 will be explained. FIG. 4 illustrates the method in the order of steps, and the element 1 has two lead wires 2 as an example. This element 1 is powder coated by a fluidized dipping method. The powder in the powder tank 4 is fluidly brought into contact with the heated element 1, so that the powder adheres to the surface. After powder coating, resin 3 is applied to the entire area including the base of lead wire 2.
It is in a semi-hardened state. At this point, the base of the lead wire 2 is removed and the resin 3 is cut so that the bottom of the resin 3 becomes flat. Hereinafter, this cut surface will be referred to as a reference surface 3A, and the resin at the base of the lead wire will be referred to as a dripping resin 3B.

Next, the tip of the dripping resin 3B is cut off to form 3B(1), which is then heated and cured to form a product. At this time, sauce resin 3B
(11 deforms again and becomes dripping resin 3 B +21.

When shipping the above-mentioned product, the lead wire 2 is cut to a predetermined length according to a user's request, and then shipped. At this time, as shown in FIG. 5, in consideration of the user's request, the distance between the lead cut surface 5 and the reference surface 3A is determined,
For example, the lead wire 2 is cut at the 4th point.

What the user really wants is for the protruding length of the lead wire to be constant when mounted on a printed circuit board, but in the above method, the reference surface 3A and the dripping resin 3Bfl are in a semi-cured state.
), so after heat curing treatment, the dripping resin 3B
fl) The cutting surface becomes sagging as shown in 21, and the distance between the reference surface 3A and the tip of the sagging resin 3 B !2 becomes different. Therefore, even if the lead wires 2 are cut to the correct dimensions from the reference surface 3A, there is a drawback that the protruding lengths will vary when mounted on a printed circuit board.

An object of the present invention is to eliminate the above-mentioned drawbacks and to provide an electronic component in which the lead wires are cut so that the length of the portion of the lead wires protruding from the back side of the printed circuit board and the protrusion length are constant when mounted on the printed circuit board. The purpose is to provide a manufacturing method.

[Means to solve the problem]

In the present invention, in a resin-clad electronic component using the date coating method, after resin coating, the exterior resin is cured, and then the tip of the dripping resin at the base of the lead wire is removed and the tip of the lead wire is cut on the cut surface.・The distance between the cutting surfaces is kept constant and the cutting is done at the same time.

[Effect]

Since the lead wires are cut and the dripping resin is removed after the exterior resin has hardened, the external dimensions of the resin do not change thereafter. Then, the lead wire and the resin dripping are cut so that the distance between the cut surface of the resin dripping at the base of the lead wire and the cut surface at the tip of the lead wire is a predetermined value, so that electronic components can be mounted on the printed circuit board. Sometimes, when the above-mentioned dripping resin is supported in contact with the surface of the printed circuit board, the protruding length of the tip of the lead wire from the back surface of the printed circuit board becomes constant for each lead wire.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows an example of a film capacitor coated with powder, and FIG. 1 particularly shows how the lead wires are cut. Figure 2 shows the lead wire 2 after curing the exterior resin.
The process up to cutting the dripping resin 3B' is illustrated. After the heating and curing process is completed, the tape holding the lead wire 2 is removed and the product is ready for use. At this time, the resin at the base of the lead wire 2 becomes a dripping resin 3B' due to curing.

Next, the lead wire 2 is cut to a predetermined length according to the user's request. This cutting is performed by cutting off the dripping resin 3B' and cutting the lead wire 2 at the same time, using a cutting jig as shown in FIG. 1, for example.

The cutting jig IO is a rectangular block consisting of a fixed part 10A and a moving part 10B.The lead wire 2 is fitted between the fixed part 10A and the moving part 10B, and the moving part 10B is moved in the direction of the arrow. This is to remove the dripping resin 3B' and cut the lead wire 2.

The fixed part 10A and the moving part 10B are provided with a cutting part 11 having a fine blade-like protrusion and having a certain length in the vertical direction in a part surrounding the lead wire 2, and a cutting part 11 having a certain length in the vertical direction. A cutting blade 12 is provided in the portion that surrounds. The distance between the upper end of the cutting portion 11 and the cutting blade 12 (denoted as H in the figure) is defined by the cutting jig IO. In FIG. 1, H=411.

The value of H is appropriately determined based on the thickness of the printed circuit board used and the length of protrusion from the back surface of the printed circuit board.

First, lead electronic components from above! 2 is the cutting jig 10
It is inserted so that it fits between the fixed part 10A and the moving part 10B. The depth of insertion at this time is such that the bottom surface of the resin almost touches the top surface of the cutting jig 10. However, as shown in FIG. 1, there is no problem even if they are not in close contact and there is a slight gap between them. After supporting the electronic components in this way, the moving part 1
When 0B is moved inward, the tip of the lead wire 2 is cut by the cutting blade 12 and the dripping resin 3
B' is crushed by the fine cutting edge of the cutting section 11.

When the electronic component is pulled upward, the crushed portion is removed from the dripping resin 3B'. As a result, the exposed length of the lead wire 2 is exactly the value H determined by the cutting jig 10 from the tip of the dripping resin 3B' to the tip of the lead wire 2.

FIG. 3 shows actually measured data regarding the protrusion length from the back surface of the printed circuit board when the electronic component according to the present invention and the final shipment product of the electronic component according to the conventional method are mounted on the printed circuit board. As shown in Figure 3 tc+, the printed circuit board is 1.5
The target is u + thickness, the lead wire length is 4 lengths, and 2
The protruding length of the lead wire of the book was measured. Since there are 10 materials, there are 20 pieces of measurement data. Figure 3 (a) shows the measurement data of the present invention, and Figure 3 (bl is the measurement data of the conventional product. As can be seen from this example, the data of the present invention is collected with high accuracy, whereas the data of the conventional product is The variation is extremely large.

〔Effect of the invention〕

As explained above, in the present invention, when cutting the lead wires of dip-coated resin-clad electronic components, after the resin hardens,
Since the dripping resin and the lead wire tip are removed and cut at the same time, the distance between the dripping resin tip and the lead wire tip can be precisely maintained. When mounting electronic components on a printed circuit board, the cut surface of the lead wire hanging resin touches the surface of the printed circuit board, and this serves as a reference, so the length of the lead wire protruding from the back of the printed circuit board must be strictly uniform. It will become fixed.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the situation in which lead wires are cut using a jig in an embodiment of the present invention, Fig. 2 is a process diagram from resin coating to lead wire cutting, and Fig. 3 is a diagram showing how the lead wires are cut when mounted on a printed circuit board. Figure 4 shows the measurement data of the lead wire protrusion length from the back side of the printed circuit board for the present invention and the conventional product.
FIG. 5 is a diagram showing a process of a conventional example. 1-Electronic component body, 2-Lead wire, 3-Resin, 3
A-Reference surface, 3B, 3B'... Sagging resin, 5- Lead cutting surface, IL- Cutting jig, 10A--Fixed part, l0B-- Moving part, 11- Cutting part, 12-- cutting blade.

Claims (1)

[Claims] In resin-clad electronic parts that have multiple terminal lead wires arranged in parallel on the same side of the main body and are coated with resin using the dip coating method, after the resin coating, the exterior resin is cured, and then the tips of the sagging resin at the base of the lead wires are coated. 1. A method of manufacturing an electronic component, characterized in that cutting off the lead wire and cutting the tip of the lead wire are performed simultaneously with a constant interval between the cut surfaces and the cut surfaces.