JPH04284925A - Dambar cut punch guide - Google Patents

Abstract

PURPOSE:To obtain a dambar cut guide possible to satisfactorily guide a damabar cut punch used to dambar cut a lead frame with fine pitch and easy to manufacture. CONSTITUTION:In the dambar cut punch guide wherein guide holes 32 to guide comb-teeth shaped blades 10 provided at the tip of the dambar cut punch are provided and the dambar cut punch is guided to perform the dambar cutting, continuous hole 32a linearly continued at one end face position of the comb-teeth shaped blade 10 is provided on one outside surface of the dambar cut punch, slit holes 32b to guide the cutting blade B of each comb-teeth shaped blade 10 are formed and the continuous hole 32a and the slit holes 32b are communicated to form the guide hole 32.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dam bar cut punch guide.

0002

2. Description of the Related Art After a lead frame is sealed with a resin, a dam bar connecting adjacent outer leads is cut and removed to separate the outer leads. FIG. 3 shows a lead frame after being sealed with resin, in which 2 is a resin sealing part, 4 is a dam bar, and 6 is an outer lead. When cutting the dam bar, punch the dam bar cut portion 8 with a dam bar cut punch as shown in the figure. The dam bar cut is performed using a dam bar cut punch 12 having a comb blade 10 at its tip, as shown in FIG. 4, in order to remove the portion connecting the outer leads. Comb blade 10
is formed to match the arrangement interval of the outer leads 6 and to have a cutting width between the outer leads 6.

[0003] The outer lead spacing of the lead frame is extremely small, and the comb blades of the dam bar cut punch are therefore extremely narrow. For this reason, when actually performing dam bar cutting, a guide portion for guiding the comb blades is provided on the stripper plate so that the dam bar is removed while supporting the comb blades. FIG. 5 illustrates a state in which the dam bar cut punch 12 is attached to a processing machine. Guide holes 16 are provided in the stripper plate 14 with a constant clearance corresponding to each of the comb blades 10, and the dam bar cut punch 12 is inserted into the stripper plate 1.
4 and the dam bar cut is made.

[0004] The guide part that guides the comb blade of the dam bar cut punch is processed with a certain clearance by polishing or wire cutting, but since the comb blade of the dam bar cut punch is extremely thin as mentioned above, these Machining the guide part is not easy. Figure 6, Figure 7,
FIG. 8 shows an example of the configuration of a conventional guide section. FIG. 6 shows a stripper plate 14 in which a guide 18 is inserted and installed, and FIG. 7 shows a guide hole filled with resin 20 for guiding. FIG. 8 shows an example in which the guide portion of the stripper plate 14 is divided and installed. FIG. 8(a) shows a cross-sectional view, and FIG. 8(b) shows a plan view.

[0005]

However, the guide portion of the conventional dam bar cut punch requires time and effort to process, and when the guide portion is formed by dividing it, there is a problem that the cumulative tolerance becomes large. In addition, in recent years, the number of pins in lead frames has increased, and the lead density has become even higher.As a result, the comb blade of the dam bar cut punch has inevitably become extremely thin, making it increasingly difficult to process the guide portion that guides it. There is a problem with becoming. In the conventional dam bar cut punch, the width of the comb blade is 1mm.
In the past, 0.15 mm to 0.
．． A diameter of about 25 mm is required, and it has become impossible to accurately guide the dam bar cut punch with the conventional guide section configuration.

[0006] The present applicant previously proposed a punch guide that facilitates microfabrication (Utility Application No. 2-65147).
No.) I did. This punch guide has a guide hole in the long hole that guides the comb blade to facilitate the machining of the guide hole, while the outer surface of the dam bar cut punch is guided by a separate member so that the comb blade can be positioned at a predetermined position within the guide hole. It is designed so that it can be maintained. Therefore, this guide method has a processing problem in that the nest must be set on the side of the dam bar cut punch.

FIG. 2 is an enlarged explanatory diagram showing a state in which the comb blades of the dam bar cut punch are guided by guide holes. Because the dam bar cut punch is a consumable part and there are restrictions on processing, the corners of the comb blade 10 are not chamfered. Therefore, the comb blade 10 is placed on the punch guide side.
It is necessary to process the corners of the A indicates the width size of the comb blade 10, and as mentioned above, if the width A is 0.
Comb blade 1 is extremely narrow at 15 mm to 0.25 mm.
If each corner of the punch is rounded, a guide portion for the comb blade cannot be formed on the punch guide, or even if a guide portion can be formed, it will only be about 0.05 mm wide. As a result, there is a problem that accurate guidance cannot be provided. Therefore, the present invention has been made to solve the above problems, and its purpose is to easily apply it to lead frames in which leads are formed at high density, and to reduce the number of parts. The present invention aims to provide a dam bar cut punch guide that can be manufactured with high precision and that makes it easy to assemble a processing machine.

[0008]

Means for Solving the Problems The present invention has the following configuration to achieve the above object. That is, in a dam bar cut punch guide that is provided with a guide hole for guiding a comb blade provided at the tip of a dam bar cut punch and that guides the dam bar cut punch to perform a dam bar cut, the guide hole is inserted into the dam bar cut punch. On one outer surface of the dam bar cut punch, a continuous hole is provided in a straight line at one end surface of the comb blade, and on the other outer surface of the dam bar cut punch, a slit hole is provided to guide the cutting edge of each comb blade. The continuous hole and the slit hole are provided in communication with each other. In addition, for the slit hole that guides the comb blade at the outermost position of the dam bar cut punch, a guide part that guides the cutting edge of the comb blade and the other end surface in the longitudinal direction of the comb blade is provided. The slit hole for guiding a comb blade other than the comb blade is characterized in that the other end surface in the longitudinal direction of the comb blade is in a free state.

[0009]

[Operation] Position and set the dam bar cut punch in the guide hole of the dam bar cut punch guide. One end surface of the comb blade of the dam bar cut punch is guided by the inner wall surface of the continuous hole, and the cutting edge of the comb blade is guided by the inner wall surface of the slit hole to perform the dam bar cut. The dam bar cut punch guide is formed as a single piece having a continuous hole and a slit hole communicating with the continuous hole.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 shows a plan view of an embodiment of a dam bar cut punch guide according to the present invention. The figure also shows the state in which the dam bar cut punch guide is being guided. The dam bar cut punch guide according to the present invention is characterized in that it is configured to guide a dam bar cut punch as an integral part, and guides the cutting edge B portion of the comb blade 10 provided on the dam bar cut punch with a predetermined clearance. , so that the longitudinal position of the comb blade 10 can also be guided within the guide hole.

That is, in the dam bar cut punch guide of the embodiment, all the comb blades 10 are attached to the punch guide member 30.
A continuous guide hole 32 is bored between the holes, and the outer shape of the guide hole 32 is linearly continuous at the outer surface position of the comb blade 10 on one outer surface of the dam bar cut punch, and continuous in a straight line at the outer surface position of the comb blade 10 on one outer surface of the dam bar cut punch. On the outer surface, each comb blade 10 is formed in a continuous shape along the outer contour line. If the guide hole portion that linearly connects one outer surface of the dam bar cut punch is a continuous hole 32a, and the guide hole of the comb blade 10 portion is a slit hole 32b, the overall shape of the guide hole is the same as the outside of the dam bar cut punch. A plurality of slit holes 32b are formed to communicate with each other at intervals of the comb blades 10 on the sides of a continuous hole 32a that is formed parallel to the side surface.

The slit hole 32b is formed with a predetermined clearance according to the width size of the comb blade 10,
The inner wall surface of the slit hole 32b serves as a guide wall that guides the comb blade 10 in the width direction. As shown in the figure, the slit hole 32b extends at least across the cutting blade B portion to the vicinity of one end of the comb blade 10. The inner wall surface of the continuous hole 32a constitutes a guide wall that guides one end surface of the comb blade 10 in the longitudinal direction. On the other hand, the other longitudinal end surface of the comb blade 10 is guided by the longitudinal end surface of the slit hole 32b, but since the comb blade 10 is extremely narrow, the end surface of the slit hole 32b is processed as a guide wall of the comb blade 10. Doing so would exceed the processing limit. Therefore, except for the slit holes 320b and 320b that guide the outermost comb blades 10a and 10b of the dam bar cut punch, the longitudinal end surface of the slit hole 32b has an arc shape connecting the corner portions as shown in the figure. shall be. Regarding the slit holes 32b at these intermediate positions, one end surface of the comb blade 10 is guided by the continuous hole 32a, but the other end surface is not guided.

On the other hand, the slit holes 320b, 3 guide the comb blade 10 located at the end of the dam bar cut punch.
20b is formed so as to guide the cutting edge B portion of the comb blade 10 and also guide the other end surface in the longitudinal direction of the comb blade 10. That is, these slit holes 320b
, 320b, the corner where the other end side of the comb blade 10 comes into contact is rounded as shown in the figure to form a relief portion 34.
, 36 are formed to form a guide portion C that guides the other end surface of the comb blade 10. The relief portion 34 is formed outwardly on the outward facing surface of the comb blade 10, and the relief portion 36 is formed on the outward facing surface of the comb blade 10.
Formed outward parallel to the longitudinal direction on the inward facing surface of the By forming the relief parts 34 and 36 at right angles to each other, they can be formed without interfering with each other. The reason why the relief portion 36 formed on the inward surface of the comb blade 10 is formed in the longitudinal direction is to prevent the relief portion 36 from interfering with the adjacent slit hole 32b. Escape part 34
Since the comb blades are formed outward from the outermost comb blade, the problem of interference with adjacent slit holes can be avoided. For lead frame products in which fine-pitch leads are formed, it is necessary to take into account interference with adjacent guide holes when designing corner reliefs. Wire cutting can be suitably used when performing very fine processing like the dam bar cut punch guide in the above embodiment. In particular, in the case of this embodiment, since all the inner walls of the guide hole are set to be continuous, processing by wire cutting is more effective.

The dam bar cut punch guide of the above embodiment can be obtained by performing predetermined processing on an integral punch guide member. It becomes easier to manufacture and improves accuracy. Also,
There are advantages in that manufacturing efficiency can be improved and material costs can be saved, making it possible to reduce manufacturing costs.

[0015]

According to the dam bar cut punch guide according to the present invention, as described above, a punch guide used for machining dam bar cuts of a lead frame formed at a fine pitch can be manufactured with high precision. Moreover, it has remarkable effects such as being able to reduce manufacturing costs.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embodiment of a dam bar cut punch guide.

FIG. 2 is an explanatory diagram showing an example of forming guide holes.

FIG. 3 is an explanatory diagram showing a dam bar of a lead frame.

FIG. 4 is a perspective view of a dam bar cut punch.

FIG. 5 is an explanatory diagram showing a guiding method for a dam bar cut punch.

FIG. 6 is an explanatory diagram showing a conventional example of a guiding method for a dam bar cut punch.

FIG. 7 is an explanatory diagram showing a conventional example of a guiding method for a dam bar cut punch.

FIG. 8 is an explanatory diagram showing a conventional example of a guiding method for a dam bar cut punch.

[Explanation of symbols]

4 Dam bar 6 Outer lead 10, 10a, 10b Comb blade 12 Dam bar cut punch 14 Stripper plate 16 Guide hole 18 Guide 30 Punch guide member 32 Guide hole 32a Continuous hole 32b, 320b slit hole 34, 36 Relief part

Claims (2)

[Claims] 1. A dam bar cut punch guide that is provided with a guide hole for guiding a comb blade provided at the tip of a dam bar cut punch and that guides the dam bar cut punch to perform a dam bar cut. On one outer surface of the bar cut punch, a continuous hole is provided that continues linearly at one end surface of the comb blade, and on the other outer surface of the dam bar cut punch, the cutting edge of each comb blade is guided. A dam bar cut punch guide characterized in that a slit hole is formed and the continuous hole and the slit hole are provided in communication with each other. 2. A slit hole that guides the outermost comb blade of the dam bar cut punch is provided with a guide portion that guides the cutting edge of the comb blade and guides the other end surface in the longitudinal direction of the comb blade, 2. The dam bar cut punch guide according to claim 1, wherein the slit holes for guiding the comb blades other than the outermost comb blades have the other end surface in the longitudinal direction of the comb blades in a free state.