JPH0847939A - Production of circuit molding - Google Patents

Abstract

PURPOSE:To prevent deformation and disconnection of a lead and a short circuit between the leads in injection molding even if the pitch of the lead is made small by fixing a plurality of lead parts of a lead frame through an adhesive or an adhesive tape in the preceding process of molding, and using these lead parts as an insert and performing injection molding. CONSTITUTION:In a lead 2 and a frame 3 used as an insert, a plurality of pieces of leads 2 are fixed by coating or sticking the central part of the lead 2 which is most easily deformed in molding with an adhesive or an adhesive tape 4, and performing heating if necessary. Then, the lead 2 and the frame 3 in which such treatment as this has been performed are set in a molding die as the insert and thermoplastic resin is poured into a cavity and molded to obtain a resin molding 1. Then the frame 3 is cut to obtain the final moldings.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a circuit molded article for preventing deformation of leads and short circuit between leads when a lead frame is insert-molded with a thermoplastic resin as an insert. .

[0002]

2. Description of the Related Art Generally, a circuit molded product having a lead frame inserted therein uses a low-viscosity material,
Prevents disconnection and short circuit between lead wires. In recent years, the lead pitch in circuit molded products has become smaller with the increasing density of electronic components. When injection molding is performed using a thermoplastic resin, the melt viscosity in the mold during molding is higher than that of a thermosetting resin, so the flow resistance of the resin causes the leads to move and deform, and in some cases short circuits occur. appear.
Therefore, in the case of a circuit having a narrow lead pitch, it is the fact that it is rarely used for a thermoplastic resin.

[0003]

DISCLOSURE OF THE INVENTION The present invention is a method for producing a molded article having a circuit by insert molding. Even when the lead pitch becomes small, when a thermoplastic resin is used, the lead of The purpose of the present invention is to prevent deformation, disconnection and short circuit between leads, and to provide a simple and extremely effective manufacturing method.

[0004]

SUMMARY OF THE INVENTION The present invention is a method of manufacturing a circuit molded article by injection molding of a thermoplastic resin with a lead frame as an insert, wherein a plurality of lead portions of the lead frame are bonded with an adhesive or A method for producing a circuit molded product is characterized in that it is fixed with an adhesive tape, and thereafter, this is used as an insert and injection molding is performed.

The present invention will be described below with reference to the drawings.
FIG. 1 is an example of a circuit molded product obtained by the present invention,
(1) is a resin molded product, and (2) is a lead. The lead (2) is partially embedded in the molded product, and the rest is integrated with the molded product on the surface of the molded product. This shape is an example, and when the lead wire is substantially embedded in the molded product, on the contrary, when it is entirely on the surface of the molded product, and when part of the molded product is not covered at all. Of course, there are various shapes such as when a part of the molded article is projected.

2A to 2C show steps for manufacturing the molded article of FIG. 1, wherein FIG. 2A is a plan view and FIG. 2B is a side sectional view of FIG. (A) shows a lead frame used as an insert, (2) shows a lead, and (3) shows a frame. In this lead frame, an adhesive or an adhesive tape (4) is applied or affixed to the central portion of the lead, which is most likely to be deformed at the time of molding, and if necessary, heated to fix a plurality of leads (B). Then, the lead frame thus treated is set as an insert in a molding die, and a thermoplastic resin is injected into the cavity for molding. (C) is a resin molded lead frame,
(1) shows a resin molded product. Then, the frame is cut to obtain a final molded product (D).

The lead portion fixed with an adhesive or an adhesive tape is not limited to one place, but is a portion that is easily subjected to resin injection pressure during molding, a portion with a small lead pitch, a portion with a small lead width or lead thickness, The lead has a complicated shape and is a portion that is easily deformed, and its position can be determined by experiment, trial production, etc., if necessary.
The adhesive or the adhesive tape can be used as long as it does not melt, shrink or expand depending on the temperature of the injected resin or the injection pressure, and is not particularly limited.

[0008]

According to the method of the present invention, even when a lead frame having a small lead pitch is injection-molded by using a thermoplastic resin as an insert, the conventional defects such as deformation of the lead, disconnection and short-circuiting between the leads are caused. Since it can be molded without causing the occurrence, it is suitable as an industrial method for manufacturing a circuit molded product.

[Brief description of drawings]

FIG. 1 is a perspective view of an example of a circuit molded product obtained by the present invention.

FIG. 2 is a manufacturing process of the molded product of FIG. 1, (a) is a plan view, and (b) is a side sectional view.

[Explanation of symbols]

 1 Resin molded product 2 Lead 3 Frame 4 Adhesive or adhesive tape

Claims (1)

[Claims] 1. A method of manufacturing a circuit molded article by injection molding of a thermoplastic resin using a lead frame as an insert, wherein a plurality of lead portions of the lead frame are fixed with an adhesive or an adhesive tape in a step before molding. A method for producing a circuit molded article, which is characterized by performing injection molding using this as an insert after that.