JP2546977B2 - Lead molding die - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead forming die for bending and forming IC external leads.

[0002]

2. Description of the Related Art Conventionally, an external lead of an IC has been formed by a mold so that its tip portion is aligned with a wiring pad of a corresponding printed circuit board in preparation for mounting on a printed circuit board or the like. .

When molding the external lead, there has been a problem that the plating layer on the surface of the external lead is peeled off due to friction between the molding punch and the external lead. Japanese Patent Laid-Open Nos. 2-58859 and 3-22467 disclose a mold for solving the problem of plating peeling.

FIGS. 2A and 2B are views showing an example of a conventional lead forming die. For example, JP-A-2-58
As shown in FIG. 2, the mold disclosed in Japanese Patent No. 859 discloses a recess that encloses the outer shell 8 of a semiconductor device, a punch 1d and a die 9 that sandwich the outer lead 8a between the peripheral surfaces of the recess, and the die 1.
d and the bending roller 5 that rolls along the side surface of the die 9, the rack 11 and the pinion 10 that rotate the bending roller 5.
And a roller mechanism 20 having

In this mold, the bending roller 5 is forcedly rotated by the pinion 10 and the rack 11 to bend the outer lead 8a, so that the outer lead 8a is bent by rolling contact with the pinion 10 and the rack 11 so that the outer lead 8a is bent. Since the molded product is molded without being squeezed by the bending roller 5, the external lead 8a can be molded without peeling of the plating.

FIGS. 3A and 3B are sectional views showing another example of the conventional lead forming die. On the other hand, the mold disclosed in Japanese Patent Application Laid-Open No. 3-22467 includes a first mold for bending the tip portion of the external lead 28 in FIG.
The second die shown in (b) and the second die that is bent from the root portion are separated from each other.

Then, first, a pad 24a of the upper die 21 and a shedder 25 of the lower die 22 are formed by a first die enclosing the resin body 27.
The tip of the external lead 28 held by a is bent by the roller 26 rolling in the direction of arrow 24. Next, the root portion of the outer lead 28 whose tip is bent by the second die is connected to the pad 24b of the upper die 21b and the shedder 25b of the lower die 22b.
Then, the punch 23a is swung as shown by an arrow 29, and the surface of the outer lead 28 is pressed vertically to perform bending.

When this metal mold is also bent, by providing a roller 10 that bends by rolling contact and a punch 3a that pushes perpendicularly to the lead surface, the outer lead can be formed without causing sliding friction on the surface of the outer lead. Therefore, it was characterized in that it could be molded without removing the plating of the external leads.

[0009]

Although the external leads formed by any of the above-described conventional IC lead forming dies have no peeling of plating, they have various new problems as dies. For example, in the former mold, the structure of the mold is complicated by providing a mechanism for rotating the bending roller. Also, although a rack and pinion mechanism is used as this rotating mechanism, this rack and pinion is liable to cause vibration due to backlash, and this vibration is directly transmitted to the bending roller to give a dent mark to the external lead formed. Become. These dent marks cause corrosion and cause problems of quality higher than the plating peeling. In particular, in this mold, since the rack is provided separately for the upper mold and the lower mold, the pinion disengaged from the rack of the upper mold gives a great impact to the bending roller when meshing with the rack of the lower mold. This will help the generation of dent marks on the lead.

Further, in the latter case of a mold having a simplified structure separated into two molds, the mold itself has to be two molds, and a transfer device between the molds and a press machine corresponding to each are required, which is very large. There is a problem that not only the equipment initial cost is wasted, but also the molding time is increased due to the separation of the bending process into two and the molding cost is increased.

Therefore, an object of the present invention is to provide an inexpensive lead forming die for an IC, which can be formed without causing the peeling of the plating layer of the external leads or the generation of dent marks.

[0012]

A feature of the present invention is that a first recess for accommodating a lower half of an outer casing of an IC package and a root portion of an external lead protruding from the outer casing are placed and the recess is formed. A die having a horizontal first surface disposed on the periphery, an inclined surface continuous with the first surface and having a predetermined angle outward, and a second surface continuous with the inclined surface and extending to a side end; A second recess for accommodating the upper half of the outer shell, and a horizontal third face which is arranged around the second recess and cooperates with the first face to hold the root of the outer lead. This third
And a shedder having a vertical fourth surface that is continuous with the outer surface and forms an outer surface, and comes in contact with the fourth surface of the shedder and descends while rotating, and bends outward from the root of the external lead and descends. Accordingly, a roller that presses the bent portion against the inclined surface and the second surface, and a roller that rotatably attaches the roller and descends together with the roller so that the tip of the external lead is moved to the second side. It is a lead forming die provided with a punch having, at its tip, a fifth surface parallel to the second surface pressed against the surface.

[0013]

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

FIGS. 1 (a) and 1 (b) are sectional views of a main part of a lead forming die showing an embodiment of the present invention. As shown in FIG. 1, this lead molding die mounts a recess 7 into which the lower half of the outer shell 8 is inserted and the root of an outer lead 8 a protruding from the outer shell 8 and is arranged around the recess 7. A die 3 having a horizontal holding surface 3c, an inclined surface 3a connected to the holding surface 3c and having a predetermined angle outward, and a contact surface 3b connected to the inclined surface 3a and extending to a side end; and an outer shell 8 A hollow 6 into which the upper half of the upper half is inserted, and a horizontal holding surface 1a that is arranged around the hollow 6 and works in cooperation with the holding surface 3c to hold the root portion of the outer lead 8a; A shedder 1 having a vertical outer surface 1c
Rotation that contacts the surface of the outer surface 1c of the shedder 1 and descends while rotating to bend the outside from the root of the external lead 8a and press the bent portion against the inclined surface 3a and the contact surface 3b as the outer lead 8a descends. Roller 4 and this rotating roller 4
Is rotatably mounted and descends with the rotating roller 4 to press the tip of the external lead 8a against the surface of the contact surface 3b. The punch 2 has a pressing surface 1b parallel to the surface of the contact surface 3b. I have it.

Next, the molding operation of the external lead 8a by this mold will be described. First, the depression 7 of the lower die 3
In the present embodiment, the outer body 8 is put in the mold and the mold is closed to wrap the outer body 8 with the recess 6 of the shedder 1 and the recess 7 of the die 3 and at the same time, the root portion of the outer lead 8a is sandwiched by the sandwiching surface of the shedder 1. According to, the IC, 1 with the shedder 1 and the bending die 3
It is held by being sandwiched between a and the clamping surface 3c of the die 3.

Next, the punch 2 is brought into contact with the rotating roller 4 on the outer surface 1c of the shedder 1 and lowered while rotating the rotating roller 4. As a result, the rotating roller 4 abuts on the base of the outer lead 8a, and as the punch 2 descends, the rotating roller 4 moves the outer lead 8a to the inclined surface 3a of the die 3.
Press down and rotate while descending. Then, the rotating roller 4 presses the tip portion of the external lead 8a against the contact surface 3b of the die 3 to bend the tip portion of the external lead 8a. Further, the pressing surface 1b of the punch 2 presses the tip of the external lead 8a which is repelled by the pressing force of the rotating roller 4 and more accurately forms the bending angle of the tip portion.

In this way, the outer roller 8a rolls along the outer surface of the die 3 and smoothly lowers the punch 2, so that the outer lead 8a is bent the first and the second to descend. It can be molded simultaneously in motion.
Further, since the rotating roller 4 rolls while rotating, it can be smoothly molded without causing slipping or engraving with the external lead 8a. As a result, there were no dent marks or peeling of the solder plating on the surface of the molded external lead.

The bending angle (second bending angle) of the tip of the external lead 8 is required to be about 4 degrees. This means that when the IC is solder-reflow mounted on the printed wiring board in the subsequent process, the tip of the external lead 8 has springiness when it comes into contact with the flat pad of the printed wiring board, so that the outer shell of the IC is covered. This is because the tip end is not tilted by the counterweight to be put on and the contact pressure with the pad surface is provided. In consideration of this, the external lead 8
Pressing surface 1b and abutting surface 3b that determine the bending angle of the tip of a
Is preferably inclined outwardly, for example, about 4 degrees below the horizontal plane.

[0019]

As described above, according to the present invention, a rotatable roller which comes into rolling contact is provided as a forming punch, the inclined surface on the die side is formed into a desired bending forming shape, and the external lead protruding from the sandwiched portion is held. The roller is pressed against an inclined surface with a curved shape and the roller is rolled while copying to form the external lead surface without squeezing it.Therefore, the solder plating on the external lead surface does not come off or scratches occur. There is an effect that can prevent. Further, since the outer lead can be bent and formed simply by rolling the roller along the copying surface formed on the inclined surface, the forming processing time can be shortened and the structure of the die can be simplified. There is an effect that it is possible to make it cheaper.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a lead forming die showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a conventional lead forming die.

FIG. 3 is a diagram showing another example of a conventional lead forming die.

[Explanation of symbols]

 1, 25a, 25b Shedder 1a, 3c Holding surface 1b Pressing surface 1c Outer side surface 1d, 2, 23a Punch 3,9 Die 3a Inclined surface 3b Contact surface 4 Rotating roller 5 Bending roller 6,7 Cavity 8 Outer shell 8a, 28 External lead 10 Pinion 11 Rack 20 Roller mechanism 21,21b Upper mold 22,22b Lower mold 24,29 Arrows 24a, 24b Pad 27 Resin body

Claims (2)

(57) [Claims] 1. A horizontal first first recess on which a lower half of an outer shell of an IC package is inserted and a root portion of an external lead protruding from the outer shell and which is arranged around the hollow. And a sloped surface that is continuous with the first surface and has a predetermined angle outwardly, and a second slope that is continuous with the sloped surface and extends to the side end.
A die having a face, a second recess for accommodating the upper half of the outer shell, and the first recess provided around the second recess.
And a vertical fourth surface that cooperates with the surface of the outer lead to hold the root portion of the outer lead, and a vertical fourth surface that is continuous with the third surface and forms an outer surface; A roller that comes into contact with the fourth surface, descends while rotating, bends the outer side from the root of the external lead, and presses the bent portion against the inclined surface and the second surface as the roller descends; Is rotatably mounted and descends together with the roller to press the tip of the external lead against the second surface. The punch has a fifth surface parallel to the second surface at the tip. Characteristic lead molding die. 2. The lead forming according to claim 1, wherein both the second surface of the die and the fifth surface of the punch are inclined outward and below the horizontal plane. Mold.