JPH08132451A - Cutting of resin burr of electric part - Google Patents

Abstract

PURPOSE: To cut the resin burr of an electronic part without generating horn- shaped cut residue. CONSTITUTION: A resin substrate 10 is formed by insert molding and lead terminals 2-4 are provided to the resin substrate 10 by insert molding. In this insert molding process, the resin burrs 20-24 extended from the end surfaces 10a, 10b of the resin substrate 10 having the lead terminals 2-4 led out therefrom are generated. Especially, the resin burrs 20, 22, 23, 24 have the shape protruding from the end surfaces 10c, 10d of the resin substrate 10. These resin burrs 20-24 are subjected to press cutting by pressing a punch to the region surrounded by dotted lines 25-29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin flash cutting method for electronic parts.

[0002]

2. Description of the Related Art When a resin material for an electronic component is formed by an insert molding method, a molten resin may flow out to a portion other than an engraved portion of a molded product of a mold to cause burrs.
A punch having a cutting blade and a die are used as one method of cutting the resin burr. By the way, the shape of the conventional resin burr is determined from the viewpoint of the yield of the resin material, the ease of molding the lead terminal, and the like, and is generally the shape as shown in FIG. In FIG. 6, the lead frame 51
Is formed by pressing a metal plate, and lead terminals 52, 53, 54 are integrally connected. The resin material 56 molded by the insert molding method is a rectangular body. From the end surface of the resin material 56, the lead terminals 52 to 5 are formed.
4 external connections lead out.

Resin flash 57, 58, 59, 60, 61
Extend from the two end faces of the resin material 56 where the lead terminals 52 to 54 are led out. The resin burrs 57 to 61 are respectively indicated by dotted lines 62, 63, 64, 65,
The punch is pressed against the area surrounded by 66 and is withdrawn. However, as shown in FIG.
A part of 59, 60, 61, that is, a portion located at a corner of the resin material 56 is not cut, and three-shaped cut residues 57a, 59a, 60a, 61a sometimes occur. Therefore, it is necessary to set the removal process of the one-shaped cut residues 57a to 61a as a subsequent process.

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin flash cutting method for electronic parts in which one-dimensional cut residue does not occur.

[0005]

In order to solve the above-mentioned problems, a resin flash cutting method for electronic parts according to the present invention is a resin derived from the lead terminals generated during insert molding of a resin material. It is characterized in that a resin burr extending from an end face of the material and protruding from an end face adjacent to this end face is cut by a punch.

By the above method, since the shape of the resin flash extends from the end surface of the resin material from which the lead terminals are extended and projects from the end surface adjacent to this end surface, the resin flash is cut by a punch. Then, the remaining cuts have the shape shown in FIG. 5, and the remaining cuts fall within the clearance between the resin material and the punch.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a resin flash cutting method for electronic parts according to the present invention will be described below with reference to the accompanying drawings. In the present embodiment, a semi-fixed variable resistor will be described as an example of the electronic component. As shown in FIG. 1, the lead frame 1
Is formed by pressing a long metal plate, and has band portions 1a and 1b, an arm portion 1c bridged to the band portions 1a and 1b, and a lead terminal 2 extending from the belt portion 1a.
And lead terminals 3 and 4 extending from the band portion 1b. The arm portion 1c is provided with a concave portion 5 at a connecting portion with the belt portions 1a and 1b. The material of the lead frame 1 is phosphor bronze or the like.

Next, after the lead frame 1 is sandwiched between molds, a molten resin such as epoxy is injected into the engraved portion of the molded product to insert-mold a rectangular resin substrate 10 as shown in FIG. Form by the method. The lead terminals 2 to 4 are insert-molded on the resin substrate 10, and the external connection parts are led out from the two end surfaces 10 a and 10 b of the resin substrate 10. The resin substrate 10 is provided with a hole 11 in the center and a circular recess 12 is formed around the hole 11.

In this step of insert molding, the molten resin flows out to a portion other than the engraved portion of the molded product of the die, and resin burrs 20, 21, 22, 2 are formed in the gap portion of the lead frame 1.
3, 24 occur. The resin burrs 20 to 24 are end faces 10a of the resin substrate 10 from which the lead terminals 2 to 4 are led out,
It extends from 10b. Particularly, regarding the resin burrs 20 and 23, unlike the conventional resin burrs, the arm portion 1c is different.
Since the molten resin flows out into the recess 5 provided in the resin substrate 1
It has a shape protruding from the end surface 10d of 0. Similarly, the resin burrs 22 and 24 also have a shape protruding from the end surface 10 c of the resin substrate 10.

Next, as shown in FIGS. 3 and 4, in order to press-cut the resin beams 20 to 24, the resin substrate 10 supported by the lead frame is set on the die 31, and then the punch 32 is formed. Dotted lines 25, 26, 27, 2
The resin burr 20 to 24 is pulled out by pressing against the area surrounded by 8 and 29 (see FIG. 2). The numeral 33 in FIG. 4 is a stripper.

In this way, as shown in FIG. 5, the conventional resin substrate 10 having no uncut residue is obtained. Then, the cut residue of the resin beams 20 to 24 is the resin substrate 10
Therefore, the clearance X of the punch 32 can be suppressed to the dimension X or less. As a result, the step of removing one shape cut residue is unnecessary. In the obtained resin substrate 10, the lead terminals 2 to 4 are cut along the alternate long and short dash line 40 in the figure and the lead frame 1 is cut out. Thereafter, a substantially arc-shaped resistor is formed on the surface of the resin substrate 10 with the hole 11a as the center,
Further, the driver plate is inserted into the hole 11a, and the tip end of the driver plate is pressed against the bottom surface of the recess 12 by means such as caulking to be attached to form a semi-fixed variable resistor.

The resin flash cutting method for electronic parts according to the present invention is not limited to the above embodiment, but can be variously modified within the scope of the invention. In particular, although the above-described embodiments have been described with respect to the semi-fixed variable resistor, the present invention is not limited to this, and may be any electronic component in which the insert-molded lead terminal is led out from at least one end surface of the resin material. Good.

[0013]

As is apparent from the above description, according to the present invention, the shape of the resin burr extends from the end face of the resin material from which the lead terminal is led out and projects from the end face adjacent to this end face. Therefore, when the resin burr is cut with a punch, the amount of remaining cut is suppressed to be equal to or less than the clearance dimension between the resin material and the punch. Therefore, by setting the clearance between the resin material and the punch to be small, the residual amount of cut can be reduced, and the resin flash can be cut without generating one-shaped residual cut.

As a result, it is possible to omit the step of removing one of the shape cut residues which has been conventionally provided.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a resin flash cutting method for electronic parts according to the present invention.

FIG. 2 is a perspective view showing the manufacturing process following FIG.

FIG. 3 is a plan view showing the manufacturing process following FIG. 2;

4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a plan view showing the manufacturing process following FIG. 3;

FIG. 6 is a plan view showing a conventional example.

FIG. 7 is a plan view showing a conventional manufacturing process following FIG.

[Explanation of symbols]

 1 ... Lead frame 2, 3, 4 ... Lead terminal 10 ... Resin substrate (resin material) 10a, 10b, 10c, 10d ... End face 20, 21, 22, 23, 24 ... Resin flash 31 ... Die 32 ... Punch

Claims (1)

[Claims] 1. An electronic component in which an insert-molded lead terminal is led out from at least one end surface of a resin material, wherein an end surface of the resin material led out by the lead terminal is generated during insert molding of the resin material. A resin flash cutting method for an electronic component, characterized in that a resin flash in a state of extending from the end surface adjacent to this end surface is cut by a punch.