JPH1177592A - Metallic mold device and manufacture of lead frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the inside of a hole punched earlier from being high pressure by providing a recess in an area overlapped with the hole whose material is punched of surfaces which come into contact with a stripper or a die material. SOLUTION: A recess 7 is provided in an area which comes into contact with a hole 6 punched by a punching block earlier of surfaces which come into contact with a metallic bar stock 1 of a stripper 2. By providing the recess 7, space surrounded by the stripper 2, a die and the metallic bar stock 1 is not filled with stamping oil and a cavity is produced in the part of the recess 7, even if stamping oil flows into the hole 6 punched earlier. Air within this cavity absorbs pressure and becomes an air cushion, and the inside of the punched hole 6 can be prevented from being high pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die apparatus for performing punching while holding down a material with a stripper, and a method for manufacturing a lead frame.

[0002]

2. Description of the Related Art Conventionally, when punching a fine product such as a lead frame, an unnecessary portion is punched out of a metal strip by a press die, but it is difficult to punch at a time. It is done separately.

[0003]

However, when the through-hole punched in the previous step is held down by a stripper in the subsequent punching step, stamping oil may flow into the through-hole in some cases. Since the stamping oil is compressed by the stripper, the die and the material, and the stamping oil is harder to compress than the air, the pressure inside the through-hole becomes high, giving a large stress to the periphery of the through-hole, and the periphery of the through-hole. In some cases, the product part was deformed.

In particular, in punching a lead frame, both side surfaces of each lead are formed one by one, and punching of a second side surface is performed in several steps because it is difficult to perform all the leads in the same step. In a later step, the leads punched out on both sides and the through holes on both sides must be held down by a stripper.

[0005] In addition, the tip of the lead may be formed in a process after the formation of the side surface of the lead.
In the process after the formation of both sides of the lead, the through holes on the lead and both sides had to be held down by a stripper.

In such a case, if the stamping oil flows into only one of the through holes, only the through hole filled with the stamping oil has a high pressure. Was sometimes deformed.

The present invention has been made in view of the above problems, and even when stamping oil flows into a previously punched through hole, a high pressure is applied to the inside of the through hole when the stripper presses the metal strip. In the process after forming both sides of the lead and the mold device that can prevent the lead from being formed, even if the through holes on the leads and both sides are held down by the stripper, the inside of the previously punched through hole is high. An object of the present invention is to provide a method for manufacturing a lead frame, which can prevent pressure from occurring and can prevent lead deformation.

[0008]

SUMMARY OF THE INVENTION A feature of the mold apparatus of the present invention is that, in a mold apparatus which performs punching while pressing a material with a stripper, the surface of the material in contact with the material of the stripper or die is punched. That is, a depression is provided in a region overlapping with the through hole.

Another feature is that the depression has an opening so that when the stripper presses the material, the punched through hole is not sealed.

A feature of the method for manufacturing a lead frame according to the present invention is a method for manufacturing a lead frame, in which punching is performed while pressing a material with a stripper. Punching using a stripper or a die provided with a depression in a region overlapping with the above.

Another feature is that an opening is provided in the depression, and when the stripper presses the material, the punching is performed so that the punched hole is not sealed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method for manufacturing a lead frame using the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, in the mold apparatus of this embodiment, a metal strip 1 is inserted between a stripper 2 and a die 3, the metal strip 1 is pressed by the stripper 2, and the metal material is It has a punching configuration.

Further, in this mold apparatus, a plurality of punched blocks are arranged at regular intervals, and the metal strip 1 is punched sequentially in each block to form a lead frame.

FIG. 2 shows a part of the area to be punched in each block. The side surfaces of the leads 5 are punched one by one, and the second side surfaces of the leads 5 are all punched out. Since the lead 5 is not performed in the same block, the lead 5 whose both sides are punched first is held by the stripper 2 together with the through holes on both sides in the subsequent block.

In the present embodiment, as shown in FIG. 3, a recess 7 is provided in a region of the surface of the stripper 2 in contact with the metal strip 1 in contact with the through hole 6 punched by the punching block.

By providing the recess 7, even if the stamping oil flows into the previously punched through hole 6,
The space surrounded by the stripper 2, the die 3, and the metal strip 1 is not filled with stamping oil, and a cavity is formed in the recess 7, and the air in the cavity absorbs pressure to serve as an air cushion, and the punched through hole is formed. High pressure inside the hole 6 can be prevented.

An opening 8 is formed in a region of the stripper 2 which is in contact with the metal strip 1 and which is particularly easily deformed and which is in contact with the through holes on both sides of the lead 5 whose both sides are punched.
Is provided, and when the stripper 2 presses the metal strip 1, it is possible to prevent the through-hole 6 punched out earlier from being sealed.

In this embodiment, the opening 8 as shown in FIG. 3 is provided. However, as shown in FIG. 4, the portion coming into contact with the stripper 2 or the lead 5 of the die 3 is directed toward the side surface of the metal strip 1. A taper may be provided, and an opening 8 may be provided in a portion overlapping the side surface of the metal strip 1.

In this embodiment, the recess 7 is provided only in the stripper 2, but the same effect can be obtained by providing the recess 7 on the die 3 side as shown in FIG.

[0021]

According to the mold apparatus of the present invention, a recess is provided in a region in contact with the previously punched through-hole.
Even if the stamping oil flows into the pre-punched through hole, when the stripper presses the metal strip, the space surrounded by the stripper, die, and metal strip is not filled with stamping oil, and A cavity is formed, and the air in the cavity absorbs pressure to serve as an air cushion, so that it is possible to prevent the inside of the through hole from becoming high in pressure.

Further, since the stripper is provided with a depression having an opening in the surface in contact with the metal strip, even when the stripper presses the metal strip, the through-hole is filled with the stamping oil even when the stripper presses the metal strip. In addition, since the previously punched through hole is not sealed, it is possible to prevent the inside of the previously punched through hole from becoming high in pressure.

According to the method for manufacturing a lead frame of the present invention, even though the lead and the through holes on both side surfaces may be held down by the stripper in the process after the formation of both side surfaces of the lead, the previously punched through hole is used. Since the inside of the hole can be prevented from becoming high pressure, deformation of the lead can be prevented.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a mold apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a punching step in the embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a state in which a through hole punched out at the end of the die apparatus according to the embodiment of the present invention is held down by a stripper.

FIG. 4 is a cross-sectional view showing a state in which a previously punched through hole is held down by a stripper according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a state in which a previously punched through hole is held down by a stripper according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal strip 2 Stripper 3 Die 4 Punch 5 Lead 6 Punched through hole 7 Depression 8 Opening

Claims (4)

[Claims] 1. A die apparatus for performing punching while pressing a material with a stripper, characterized in that a recess is provided in a region of the surface of the stripper or the die that is in contact with the material, the region overlapping with the punched hole of the material. Mold equipment to do. 2. The mold apparatus according to claim 1, wherein the depression has an opening, and the punched through hole is not sealed when the stripper presses the material. 3. A method for manufacturing a lead frame, wherein punching is performed while pressing a material with a stripper, wherein the stripper or the die is provided with a recess in a region in contact with the material and overlapping a through hole formed by punching the material. A method for manufacturing a lead frame, characterized in that punching is performed using the same. 4. The method for manufacturing a lead frame according to claim 3, wherein an opening is provided in the depression, and when the stripper presses a material, the punched hole is punched so as not to be sealed.