JPH06232306A - Method of manufacturing lead frame and press-molding metallic mold use for the same - Google Patents

Abstract

PURPOSE:To manufacture acceptable lead frames having no gouge, etc., at all capable of being press-molded avoiding the tortion thereof. CONSTITUTION:This press-molding metallic mold having a punch guide 10 for hold-supporting a lead frame member 6 between the guide 10 and a die 8 is provided with a holding part for hold-supporting the surface of the lead frame member 6 between the punch guide 10 and the die 8 as well as a surfaced part 10a formed in a taper shape to surface the corner part of the outside surface of the lead in a C shape when the lead frame member 6 is hold- supported.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press molding die used for processing lead frames and the like.

[0002]

2. Description of the Related Art When a lead frame is manufactured by press working, a punch is used to form a lead.
A phenomenon occurs in which the lead is twisted during processing by this punch. The twisting of the leads is caused by the lead frame material being pulled in by a punch during press working, and is likely to occur in a product having a large material thickness and a narrow lead width, such as a lead frame for a transistor.

As a method for preventing such twisting of the lead, as shown in FIG. 4, the lead frame material is clamped and supported between the die 8 and the die 8 while pressing the upper surface of the lead frame material 6 with the punch guide 5, The method of punching with the punch 7 is conventionally performed. The conventional punch guide 5 has a pinching portion for pinching the lead frame material with the die 8 and a heel portion 5a protruding to the outer surface of the lead, and the heel portion 5a enters between the leads during press working. I try to punch while guiding the side of the lead.

[0004]

In the conventional punch guide, since the side surface of the lead is processed by guiding the side surface of the lead by the heel portion 5a of the punch guide 5, the distance between the side surface of the heel portion 5a and the side surface of the lead frame member 6 is increased. However, if the distance is narrowed, the heel portion 5a may hit the lead frame material 6 if the material is displaced from the normal position when the material is fed forward, and a dent or a shave is formed on the product. However, there is a problem in that a product may be mistakenly fed.

Therefore, the present invention has been made to solve these problems, and an object of the present invention is to effectively prevent the twisting of the leads when the lead frame is manufactured by press working. Another object of the present invention is to provide a lead frame manufacturing method capable of reliably manufacturing a non-defective product without producing dents or the like on the product, and a press molding die suitably used for this.

[0006]

The present invention has the following constitution in order to achieve the above object. That is, in a method of manufacturing a lead frame in which a lead pattern is formed by punching a lead frame material while sandwiching and supporting a lead frame material between a punch guide and a die, the lead is sandwiched and supported by the punch guide and the lead is formed. The punching process is performed while the C-face processing is performed on the corner portion of the outer surface of the substrate by the punch guide to support the lead. Further, in a press molding die having a punch guide that clamps and supports the lead frame material with the die, a clamping portion that clamps and supports the surface of the lead frame material between the punch guide and the die, When the lead frame material is clamped and supported, a corner portion of the outer surface of the lead is subjected to a C-faced processing to provide a tapered surface-shaped portion for supporting the lead.

[0007]

When the lead frame material is pressed and supported between the lead frame material and the die by the punch guide, the corner portion of the outer surface of the lead on the pre-punched side is subjected to the C-faced processing, The punch guide effectively supports the outer surface of the lead, and prevents the lead from being twisted and can be pressed. By providing the punch guide with a tapered faced portion, the lead can be effectively supported by the C-faced processing, and even if the material is misaligned, the punch guide does not cause dents or the like on the product, so that it is a non-defective product. Can be manufactured.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is an explanatory view showing the configuration of an embodiment of a press molding die used when manufacturing a lead frame. In the press molding die of the embodiment, the upper surface of the lead frame material 6 is pressed by the pressing portion of the punch guide 10 to prevent the leads from being twisted during press working, and the lead frame material 6 is formed between the lead frame material 6 and the die 8. The punch guide 10 presses the lead frame material 6 by pressing it while pressing the corner portions of the upper surface of the lead frame material 6 so as to perform C-face processing. Characterize.

For this reason, the punch guide 10 is provided with a taper-shaped imposition portion 10a for C-imposing a portion contacting the side edge portion of the lead. In the conventional punch guide, the heel portion is provided to guide the side surface of the lead, but in the punch guide of the present embodiment, the heel portion is provided to guide the side surface of the lead by only slightly protruding. No protrusion is provided. The pressing depth of the punch guide 10 is about 0.03 to 0.04 mm for a lead frame material having a thickness of 0.5 mm. Imposition section 10
If the imposition amount of a is too large, the material will be curved, so it is necessary to make the imposition amount appropriate.

FIG. 2 and FIG. 3 are explanatory views showing the processing contents for actually manufacturing a lead frame using the above press molding die. FIG. 2 shows a state in which the lead frame material 6 is sequentially fed and pressed to form a lead frame. In the figure, a portion A is a processing stage for performing the first press punching processing for forming the lead on the lead frame material 6. The hatched portion in the figure is the portion where the lead frame material is removed by punching. The punching position is set according to the position where leads are formed in the subsequent process.

FIG. 3A shows the arrangement of the punch 12 and the punch guide 14 in this punching process. In this processing stage, the lead forming area of the lead frame material 6 has not been punched yet and is the first punching, so the punch guide 14 merely guides the punch 12. In the embodiment, two punches 12 and 12 are punched at two locations at a time.

In FIG. 2, a portion B shows a processing stage which is performed subsequent to the previous pressing by the punches 12, 12. In this processing stage, a part adjacent to the previous cutting position is punched to form one lead. The shaded portion in the figure is the portion to be punched in the B stage. In the B stage, two points are punched according to the previous punching position. As a result, the two leads 16, 16 are molded.

In this punching process, the lead is punched using the above-mentioned press molding die. FIG. 3B shows the structure of the die when punching is performed by the punches 18 and 18 in the B stage. In this B stage, the punch guide 20 presses the upper surface of the lead 16 to support it by sandwiching it with the die, and as described above, presses the corner portion of the outer surface of the lead 16 so as to perform the C imposition processing and removes it. Apply processing.
Reference numeral 20a denotes an imposition section provided on the punch guide 20 for subjecting the lead to C imposition processing. The imposition portion 20a is provided for each lead 16, whereby the C imposition portion 16a is formed on the outer surface of each lead 16 as shown in FIG. Due to its structure, the C-imposition portion 16a is formed on one of the both side surfaces of the lead, which has been previously removed in the previous step.

In FIG. 2, a portion C is a stage for punching after the B stage, which is a final stage for forming leads. By passing through the C stage, a lead frame for a transistor having three outer leads is obtained. In this C stage, a wide punch is used to punch adjacent leads 20, 20 at a time.

FIG. 3 (c) shows a lead 2 using a punch 24.
The mold configuration of the C stage forming 0 is shown. Punch 24
In the case of the punching process, the punch guide 26 presses the upper surface of the lead frame material 6 as in the B stage to perform the punching process. Similarly, the punch guide 26 is provided with an imposition part 26a for the above-mentioned C imposition processing. However, in this C stage, the leads 20 are formed at one time on both sides of the punch 24. An imposition part 26a is provided for each of the leads 20 on both sides. In the embodiment, since two punches 24 are used, the punch guide 26 is provided with four imposition portions 26a.

As described above, the punch guide 26 presses and supports the lead frame material 6 to perform the punching process, so that the outer surface of the lead 20 is C-faced. Thus, according to the lead frame manufacturing method of the present embodiment, a lead frame product is obtained in which leads having a predetermined pattern are formed by punching with a punch, and one outer surface of each lead is C-faced. . According to the method of the present invention, since the lead frame material is supported and pressed by the punch guide having the imposition portion as described above, it is possible to prevent the lead from being twisted during the processing and perform the suitable pressing. It will be possible.

Since the punch guide is provided with the imposition portion, the side surface portion of the lead is reliably supported by the processing with the C surface to prevent the lead from being twisted during processing, and a thick material is used. Even in such a case, the twisting of the leads can be effectively prevented. When punching is performed with a punch, the sagging occurs at the corner of the upper surface of the lead frame material on the side where the punch abuts, but with the C imposition processing described above, the sagging portion can be effectively suppressed and the lead frame material is pressed. It is possible to expand the area to be supported and surely support the lead frame material. As a result, it is possible to counter the moment when punching the other side surface of the lead and prevent the twisting of the lead during press working.

Further, since the portion of the punch guide that presses the side surface of the lead is a tapered imposition portion, the side surface of the lead is rubbed or a dent is formed on the product even when the material is slightly displaced. There is a feature that a good product can be manufactured without fail. In addition,
Although the lead frame for a transistor has been described in the above embodiment of the manufacturing method, the method of the present invention is generally applicable to a lead frame manufactured by press working.

[0019]

As described above, according to the lead frame manufacturing method and the press-molding die of the present invention, it is possible to prevent the lead from being twisted and to perform a suitable press working, thereby making a dent or a dent on the product. A good product can be produced without producing burrs and the like, and the feedability of the material can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an embodiment of a press molding die.

FIG. 2 is an explanatory diagram showing a method of manufacturing a lead frame.

FIG. 3 is an explanatory diagram showing a configuration of a molding die for each processing stage in manufacturing a lead frame.

FIG. 4 is an explanatory view showing a configuration of a conventional example of a press molding die.

[Explanation of symbols]

 5 Punch Guide 5a Heel Part 6 Lead Frame Material 7 Punch 10 Punch Guide 10a Faced Part 12, 18, 24 Punch 14, 20, 26 Punch Guide 16, 22 Lead 20a, 26a Faced Part

Claims (2)

[Claims] 1. A method of manufacturing a lead frame in which a lead pattern is formed by punching a lead frame material while sandwiching and supporting a lead frame material between a punch guide and a die. In addition, the punch guide C
A method of manufacturing a lead frame, wherein a punching process is performed by the punch while performing a faceting process to support a lead. 2. A press molding die having a punch guide that clamps and supports a lead frame material with a die, wherein a clamping pressure that clamps and supports the surface of the lead frame material with the punch guide. And a tapered surface-shaped portion for supporting the lead by performing a C-faced processing on the corner portion of the outer surface of the lead when the lead frame material is clamped and supported. Molding die.