JPH05185467A - Resin mold die for lead frame - Google Patents

Abstract

PURPOSE:To favorably prevent resin flow at the time of resin molding by crush ing a side edge part of a lead frame and eliminate slippage between centers of the lead frame and a package by preventing positional slippage of the lead frame at the time of crushing. CONSTITUTION:In a resin mold die for a lead frame 10 having a crushing part 16 which crushes partially the part in the vicinity of a side edge part of the lead frame 10 on the side of the entry of a gate 14 so that the side edge part be jutted out and thereby stops the flow of molding resin on the occasion of positioning and clamping the lead frame 10, a positional slippage preventing crushing part 20 for preventing the positional slippage by crushing on the occasion of clamping the lead frame 10 is provided at a position being separate from the foregoing crushing part, for the purpose of preventing the positional slippage of the lead frame 10 on the mold die on the occasion of crushing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molding die for a lead frame.

[0002]

2. Description of the Related Art When a lead frame is resin-molded, the lead frame is positioned on the molding die and is clamped by the molding die for resin filling. The lead frame is positioned with respect to the molding die by inserting the pilot pin into the reference hole, but there is a deviation of about ± 0.03 mm due to hole accuracy of the reference hole and manufacturing error of the lead frame. The molding die is provided with a storage recess for setting the lead frame. Since the lead frame has the above-mentioned error, the storage recess is formed slightly larger in consideration of the error. As a result, when the lead frame is set in the molding die, a gap is created between the side edge of the lead frame and the inner edge of the accommodating recess, and there is a problem that the molding resin flows out into the gap during resin molding. ..

Therefore, in the resin molding die, a measure is taken to prevent the molding resin from flowing out from the above-mentioned gap portion. For example, a method to prevent resin from flowing out by providing a resin reservoir in the molding die where the side edges of the lead frame face each other, and crushing the side edges of the lead frame when clamping the lead frame with the molding die. For example, a method of processing to overhang the side edge of the lead frame to prevent the resin from flowing.

[0004]

FIG. 4 shows a method of preventing resin flow by the above crushing process. In the figure, 10 is a lead frame, 12 is a cavity, and 14 is a gate. Reference numeral 16 is a crushed portion obtained by crushing the lead frame.
Reference numeral 8 is an overhang portion formed by crushing. When the lead frame 10 is crushed and processed, the projecting portion 18 projects from the side edge of the lead frame 10 and abuts the inner edge of the storage recess to prevent the resin flow. By the way, the above-mentioned crushing process is performed by the molding die with the lead frame 1.
This is done when 0 is clamped, but if there is a plane distortion in the lead frame 10, the lead frame 10 will be crushed.
When one side edge portion is pressed, the opposite side of the lead frame 10 pops up and the lead frame 10 is displaced, or the lead frame 10 reacts when the overhanging portion 18 contacts the mold surface. The phenomenon that it shifts in the opposite direction occurs.

When the lead frame is displaced in this way, the center positions of the lead frame and the package are displaced so that the required standard value cannot be satisfied. Since the lead frame with many pins has been widely used these days, the standard of center misalignment is becoming stricter, and the misalignment of lead frame due to crushing during resin molding cannot be ignored. Came. Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to displace the lead frame in a molding die that is resin-molded by crushing processing for preventing resin flow. The present invention is intended to provide a molding die capable of preventing the above-mentioned phenomenon and reliably performing resin molding.

[0006]

The present invention has the following constitution in order to achieve the above object. That is, when the lead frame is positioned and clamped, the vicinity of the side edge portion of the lead frame on the side where the gate enters is partially crushed and the side edge portion is bulged to prevent the mold resin from flowing. In a resin mold die for a lead frame having a processed portion, the lead frame is clamped at a position different from the crushed portion in order to prevent the lead frame from being displaced on the molding die during the crushing processing. At this time, a crushing process is performed to prevent a position shift, and a position shift preventing crushing portion is provided. Further, in the resin molding die of the lead frame, the crushed portion of the crushing is a rail portion of the lead frame, and an inner portion of the rail portion is an empty space. It is characterized in that it is provided in the central portion to locally absorb the deformation of the lead frame during the crushing process.

[0007]

[Function] When the lead frame is clamped, the side edge portion of the lead frame is bulged by crushing the lead frame at the crushing portion to prevent resin from flowing out and crushing at the position shift preventing crushing portion. This prevents the lead frame from jumping up and prevents positional displacement. If the inner portion of the rail portion is crushed at a portion having an empty space, the deformation of the lead frame is absorbed near the rail portion, and it is possible to prevent the displacement of the lead frame without affecting other portions.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an explanatory view showing a state in which a lead frame is resin-molded by a resin molding die of a lead frame according to an embodiment of the present invention. Figure 1
1A is a plan view, and FIG. 1B is a sectional view. In the figure, the arrangement of the lead frame 10, the cavity 12, the gate 14, etc. is the same as in the conventional example. 16 is a crushed portion provided in the vicinity of the side edge portion of the lead frame 10 as in the conventional example, and 18 is an overhanging portion formed by crushing similarly. This embodiment is characterized in that the crushing process and the misalignment preventing crushing process for preventing the displacement of the lead frame 10 are provided on the other rail portion of the lead frame 10 at the same time.

In FIG. 1, reference numeral 20 designates a position shift preventing crushing portion. The position shift preventing crushing process is performed by crushing the lead frame 10 from the same side (upper die) as the side where the crushed portion 16 is formed. The crushed portion 16 projects the protruding portion 18 from the side edge of the lead frame 10,
The position shift preventing crushed portion 20 is provided at a position close to the side edge portion of the lead frame 10 and is provided at a symmetrical position in the width direction of the lead frame 10.

When the lead frame 10 is clamped and resin-molded, the crushing portion 16 presses one rail portion of the lead frame 10 and simultaneously presses the other rail portion of the lead frame 10 when the lead frame 10 is resin-molded. By doing so, the lead frame 10 is prevented from jumping up, and the lead frame 10 is held so as not to be displaced. The displacement prevention crushing portion 20 supports the lead frame 10 before completely clamping the lead frame 10 with a molding die and holds the lead frame 10 so that the lead frame 10 is not displaced as a whole. It also has a preventive action. Misalignment prevention crushed part 2
It suffices that 0 can be supported by pressing both side edges of the lead frame 10, can be provided at appropriate positions on the lead frame, may be provided at a plurality of locations, and need not necessarily be provided at symmetrical positions with the crushed portion 16.

As a method for preventing the lead frame 10 from being displaced due to the crushing process for preventing the resin flow, there is a method of holding the lead frame 10 so as not to be displaced as a whole as described above. Alternatively, it is also possible to locally absorb the deformation of the lead frame 10 due to the crushing process so as not to affect other parts of the lead frame 10. FIG. 2 shows a method for preventing displacement by this method. That is, as a portion to be crushed, the inside of the rail portion 10a of the lead frame 10 is an empty space, and a portion having a relatively narrow width is selected, and the crushed portion 16 is provided at a substantially central portion in the width direction of the rail portion 10a. Is the way. When the length L of the empty space portion is longer than the length of the crushed portion 16, the deformation due to the crushing process can be absorbed in the vicinity of the crushed portion 16 and does not affect the other parts of the lead frame 10, so that the position shift occurs. Can be prevented.

FIG. 3 shows an embodiment in which the displacement of the lead frame 10 is prevented by locally suppressing the influence of the crushing process as in the above example. This embodiment is characterized in that the round hole 24 provided in the lead frame 10 is deformed by the taper pin 26 to be used as a resin flow stop. That is, when the lead frame 10 is clamped by the molding die, the taper pin 26 is brought into contact with the round hole 24, and by pressing the taper pin 26, the round hole 24 is expanded and the protruding portion 18 is projected to prevent the resin from flowing. .. Taper pin 2
The round hole 24 isotropically spreads by abutting 6 but if the inside of the rail portion is an empty space as shown in the figure, the deformation of the round hole 24 is locally absorbed as in the above embodiment. Therefore, the other parts of the lead frame 10 are not deformed, and the lead frame 10 can be effectively prevented from being displaced due to the crushing process. Although the ordinary lead frame 10 has a guide hole in the rail portion for positioning, the round hole 24 may be a guide hole that is not used for positioning or the like. In some cases, in addition to the guide hole for positioning, another round hole may be formed for resin flow prevention processing. The method shown in FIGS. 2 and 3 is preferably used for a product in which the rail portion has a narrow width, the lead frame has good flatness, and the flip-up during clamping is not a problem.

[0013]

The resin mold die for the lead frame according to the present invention is configured as described above, and the side edge portion of the lead frame is crushed to suitably prevent resin flow during resin molding. In addition, it is possible to effectively prevent the lead frame from being displaced during the crushing process, and it is possible to solve the problem of the center displacement between the lead frame and the package. This makes it possible to carry out resin molding with higher accuracy and to achieve a remarkable effect such that it can be suitably used for resin molding of a multi-pin lead frame.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment in which resin molding is performed using a resin molding die for a lead frame.

FIG. 2 is an explanatory view showing another embodiment in which resin molding is performed using a resin molding die for a lead frame.

FIG. 3 is an explanatory view showing still another embodiment of resin molding using a resin molding die for a lead frame.

FIG. 4 is an explanatory diagram showing a conventional example in which resin molding is performed using a resin molding die for a lead frame.

[Explanation of symbols]

 10 lead frame 10a rail part 12 cavity 14 gate 16 crushed part 18 overhanging part 20 misalignment preventing crushed part 24 round hole 26 taper pin

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area B29L 31:34 4F

Claims (2)

[Claims] 1. When the lead frame is positioned and clamped, the mold resin flows by partially crushing the vicinity of the side edge portion of the lead frame on the side where the gate enters and projecting the side edge portion. In a resin mold die of a lead frame having a crushed portion to be stopped, in order to prevent the lead frame from being displaced on the mold die during the crushing treatment, the lead frame is provided at a position different from the crushed portion. A resin molding die for a lead frame, which is provided with a position shift preventing crushing portion that crushes and clamps to prevent a position shift. 2. When the lead frame is positioned and clamped, the mold resin flows by partially crushing the vicinity of the side edge portion of the lead frame on the side where the gate enters and protruding the side edge portion. In a resin molding die for a lead frame having a crushed portion for stopping, the crushed portion of the crushed portion is a rail portion of the lead frame, and an inner portion of the rail portion is an empty space. A resin molding die for a lead frame, which is provided substantially at the center in the width direction to locally absorb the deformation of the lead frame during the crushing process.