JP2001177036A - Method of cutting resin dam bar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems that a lead time is prolonged because two processes of cutting a dam bar and cutting a resin are required, and that the resin cannot be removed completely in a method of cutting the dam bar from a resin-sealed lead frame by using a punch and removing excessive resin overflow between leads. SOLUTION: A dam bar cutting punch having a comb blade aligned at a position of a dam bar between leads is equipped with a punch guide for guiding a dam bar cutting punch in an upper portion thereof. A spring is provided in the guide so that a certain pressure is applied to the dam bar cutting punch. In this state, the dam bar cutting punch is lowered. The end of the dam bar cutting punch is always brought into contact with a sealing resin to remove excessive resin overflowing between the dam bar and the leads from the lead frame while cutting the dam bar.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of cutting a dam bar from a lead frame after resin sealing, and removing excess resin protruding between leads.

[0002]

2. Description of the Related Art Heretofore, it has been necessary to perform a step of using a punch to cut a dam bar from a lead frame after resin sealing and a step of using a punch to cut excess resin protruding between leads.

There has also been a method in which a dam bar is cut from a lead frame after resin sealing using a punch, and excess resin protruding between leads is simultaneously pushed down.

[0004]

In the above-mentioned prior art, there is a problem that two steps of a dam bar cutting step and a resin cutting step are required, and the lead time becomes long.

There has also been a method in which a dam bar is cut from a lead frame after resin sealing using a punch, and excess resin protruding between the leads is simultaneously pushed down. However, it is difficult to completely remove the resin, and it is difficult to remove the resin residue. appear.

[0006]

In order to solve the above problem, a dam bar cut punch formed with a comb blade adapted to the position of the dam bar between the leads is used to protrude from the lead frame after resin sealing between the dam bar and the lead. Excess resin is cut and removed at the same time. .

A punch guide for guiding the dam bar cut punch is provided above the dam bar cut punch, and a spring is provided therein to apply a predetermined pressure to the dam bar cut punch.

When the dam bar cut punch descends in this state, the tip of the dam bar cut punch is always in contact with the sealing resin, and cuts the excess resin protruding from the lead frame between the dam bar and the lead, while also cutting the dam bar. . .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a dam bar cut punch having a comb blade formed in accordance with the position of a dam bar between leads is prepared.

A punch guide for guiding the dam bar cut punch is provided above the dam bar cut punch, and a spring is provided therein to apply a constant pressure to the dam bar cut punch.

Next, when the dam bar cut punch descends,
The tip of the dam bar cut punch is always in contact with the sealing resin, and cuts the excess resin protruding from the lead frame between the dam bar and the lead while also cutting the dam bar.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

First, in FIG. 1, a dam bar cut punch 1 having a comb blade formed at the position of a dam bar between leads is formed.
Prepare A dam bar cut die 2 provided with a hole corresponding to a comb blade is provided below the dam bar cut punch 1.

FIG. 2 is a sectional view showing a positional relationship among the dam bar cut punch 1, the dam bar 3, and the dam bar cut die 2. As shown in FIG. When dam bar cut punch 1 descends, dam bar 3
Then, the dam bar 3 is cut by the dam bar cut die 2.

FIG. 3 is a perspective view showing a state of the lead frame 5 after resin sealing. The lead frame 5 is joined to the sealing resin 6. Between the lead frame 5 and the sealing resin 6, there is an extra resin 4 protruding between the leads and a dam bar 3 for stopping the flow of the resin 4.

Next, referring to FIG. 4, an extra resin 4 protruding between the leads and a dam bar 3 for stopping the flow of the resin 4 will be described.
Will be described at the same time. A punch guide 8 for guiding the dam bar cut punch 1 is provided above the dam bar cut punch 1, and a spring 7 is provided therein to apply a constant pressurization to the dam bar cut punch 1.

When the dam bar cut punch 1 descends, the tip of the dam bar cut punch 1 is always in contact with the sealing resin 6 and cuts off the excess resin 4 protruding from the lead frame 5 between the dam bar 3 and the lead, while cutting the dam bar. Also cut. .

With the above operation, the excess resin 4 which has protruded between the dam bar 3 and the lead can be simultaneously cut and removed with only one dam bar cut punch 1.

[0019]

According to the present invention, it is possible to simultaneously cut and remove excess resin protruding between the dam bar and the lead only by the dam bar cutting step, so that the lead time can be shortened.

In addition, the resin can be completely removed because the resin is cut and removed instead of the method of dropping the excess resin protruding between the leads.

[Brief description of the drawings]

FIG. 1 is a perspective view of a dam bar cut punch and a dam bar cut die.

FIG. 2 is a sectional view showing a positional relationship between a dam bar cut punch, a dam bar, and a dam bar cut die.

FIG. 3 is a perspective view showing a state of the lead frame after resin sealing.

FIG. 4 is a detailed view of a resin / dam bar cutting method according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dam bar cut punch 2 Dam bar cut die 3 Dam bar 4 Resin 5 Lead frame 6 Sealing resin 7 Spring 8 Punch guide

Claims (1)

[Claims] The present invention is characterized in that, using a dam bar cut punch formed with a comb blade corresponding to the position of a dam bar between leads, excess resin protruding between the dam bar and the lead is simultaneously removed from the lead frame after resin sealing. Resin / dam bar cutting method.