JPH04161309A - Resin flash removing mold - Google Patents

Abstract

PURPOSE:To manufacture a mold without residual resin by providing a pressing face of a punch for pressing resin on an outer skin side parallel to a lead frame and also providing a pressing face for pressing a tie bar and resin on the outer section lead side inclined by the given angle to the lead frame. CONSTITUTION:The size of a punch Pa is on the same as that of a clearance C1 on the side of an outer skin 1 by eliminating a clearance on the side of a tie bar 3, and an inclined face 2a2 having the given angle to a pressing face 2a1 is formed and a spring 8 for pressing the punch 2a by the given pressure is installed. As the punch 2a for applying the pressing force to a resin flash 6 on the side of a tie bar 3 is formed into a structure being pressed by the spring 8 as above-mentioned, the pressing force is applied to a central section of resin flash 6 by the pressing face 2a1 of said punch 2, and also the pressing force is applied to the resin flash 6 adhered on the outer periphery on the tie bar 3 side on the inclined face 2a2, and shearing force is generated by the adhered section of resin flash 6 on the side of the tie bar 3, and said resin flash 6 can be punched without residual resin.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a resin deburring mold for removing resin burrs that adhere to various parts of a lead frame when a semiconductor chip is mounted on a lead frame and resin-sealed. .

[Conventional technology]

FIGS. 3 and 4 are cross-sectional views for explaining an example of a conventional resin deburring mold. Conventionally, this type of resin deburring mold has a die block 5 on which an outer body 1 formed by resin-sealing a semiconductor chip is mounted, as shown in FIGS. 3 and 4.
It had a dia on which the tie bars 3 and external leads 4 of the lead frame were placed, and a punch 2b for punching out the resin burr 6 protruding between the outer body 1 and the tie bars 3.

To remove resin burrs attached to various parts of a resin-sealed lead frame using this resin deburring mold, first open the mold and place the resin-sealed outer body 1 of the lead frame in the die block 5. , and other portions of the lead frame that protrude from the outer body 1, that is, the tie bars 3 and external leads 4, are positioned so as to rest on the diamond. Next, by closing the mold, the punch 2b descends to punch out and remove the resin burr 6 adhering between the tie bar 3 and the outer shell 1.

[Problem to be solved by the invention]

However, as shown in FIGS. 3 and 4, the conventional resin deburring mold described above has clearances C1 and C2 to prevent the punch 21 from coming into contact with the tie bar 3 and the external lead 4. There is. Therefore, when the punch 2b punches out the resin burr 6, resin remains on the side surface of the tie bar 3. This resin residue poses a problem of causing damage to the functional parts of the external lead cutting mold used in a later finishing step and deformation of the external lead. As a countermeasure for this problem, after the resin deburring work, a stroke number check is performed and the remaining resin is removed, which requires a large number of man-hours. The aim of the invention is to eliminate the above-mentioned drawbacks and
To provide a resin deburring mold that does not cause resin residue.

[Means for Solving the Problems] The resin deburring mold of the present invention is a resin deburring mold for a lead frame in which a semiconductor chip is placed in the center and a resin outer body is formed by resin sealing. , a die block on which the outer shell is placed, a die on which the tie bars and external leads protruding from the outer shell are placed, a punch for removing the resin body in an area surrounded by the outer shell, the outer leads, and the tie bars; a spring that applies a pressing force to a punch to remove the resin body, the punch has a pressing surface that presses the resin body on the outer shell side is parallel to the lead frame, and is on the tie bar and external lead side. The pressing surface that presses the resin body is inclined at a predetermined angle with respect to the lead frame.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIGS. 1 and 2 are cross-sectional views for explaining one embodiment of the resin deburring mold of the present invention. As shown in the figure, this resin deburring mold has a size of the punch 2a that eliminates the clearance on the tie bar 3 side and makes the clearance on the outer body 1 side comparable to C1 of the conventional example. , an inclined surface 2.2 having a predetermined angle with respect to the pressing surface 2,1
form a punch 2. The reason for this is that a spring 8 is provided to press the spring 8 with a predetermined pressure. Other than that, it is the same as the conventional example.

In this way, unlike the conventional example, the punch 23 that applies pressing force to the resin burr 6 on the tie bar 3 side is held down by the spring 8, so this punch 2. A pressing force is applied to the center portion of the resin burr 6 by the pressing surfaces 2, 1 of the inclined surface 2.
In step 2, a pressing force is applied to the resin burr 6 attached to the outer periphery of the tie bar 3 side, so shear stress is generated by the attachment part of the resin burr 6 on the tie bar 3 side, and this resin burr 6 can be punched out without leaving resin residue. I can do it.

Although not shown in the drawing, punch 2. and spring 8 are attached to the punch holder. That is, punch 2. is attached to slide inside the insertion hole of the punch holder, and the spring 8 connects the bottom of the insertion hole of the punch holder with the punch 21.
It is inserted between the heads of. Therefore, when the spring 8 is compressed to the maximum, the compressive force of the spring 8 is set to be less than the force that causes the contact interface of the resin burr 6 to peel off. Also, the inclined surface 2.
2, it is best to attach a soft material, such as a lead plate, to the tie bar 3 to prevent scratches.

〔Effect of the invention〕

As explained above, the present invention does not punch out the resin burrs, but instead presses the resin burrs on the tie bar and external lead side, which have strong adhesion, with a predetermined pressure using a spring. Against resin burrs,
By pressing with a predetermined pressure from the spring, the interface between the tie bar and the external lead and the resin can be easily peeled off, so there is an effect that a resin deburring mold with no resin residue can be obtained.

[Brief Description of the Drawings] Figures 1 and 2 are sectional views for explaining an embodiment of the resin deburring mold of the present invention, and Figures 3 and 4 are conventional resin deburring molds. It is a sectional view for explaining an example of a mold. 1. External body, 2. ... Punch, 261 ... action surface,
2.2... Working surface, 3... Tie bar, 4... External lead, 5... Die block, 6... Dam resin, 7...
...Die, 8...Spring. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] A resin deburring mold for a lead frame in which a resin shell is formed by placing a semiconductor chip in the center and sealing it with resin includes a die block on which the shell is placed, and a tie bar and a tie bar protruding from the shell. A die for mounting an external lead, a punch for removing the resin body in an area surrounded by the outer body, the external lead, and the tie bar, and a spring for applying a pressing force to the punch to remove the resin body, A pressing surface of the punch that presses the resin body on the outer shell side is parallel to the lead frame, and a pressing surface that presses the resin body on the tie bar and external lead side is at a predetermined angle with respect to the lead frame. A resin deburring mold characterized by its slope.