JP2556716B2 - Lead forming equipment - Google Patents

Description

Detailed Description of the Invention

[Industrial applications]

The present invention relates to a lead forming device that bends a terminal lead of an electronic component such as an IC into a predetermined shape.

[Prior art]

As shown in FIGS. 4 and 5, in an IC having a so-called flat type package, the terminal leads b ... Which protrude in a comb shape from both sides of the resin package portion a are bent in a crank shape. Such bending of the terminal leads b ... is performed by a die bonding process, a wire bonding process, a resin molding process, a solder plating process.
..In a series of manufacturing processes for electronic devices of this type in which work is performed on the lead frame, adjacent to the dam bar cutting process or the lead cutting process following the resin molding process or the solder plating process, or At the same time, conventionally, the following lead forming apparatus has been used. That is, as shown in FIG. 6, the conventional forming device c includes a fixed die e having left and right lower die parts d, d,
A forming punch f which is vertically moved by a hydraulic press or the like is provided above the fixed die e.
The lower mold parts d, d are located on both sides of the recessed part g for accommodating the lower half of the resin package part a and a horizontal part h for supporting the base parts of the both terminal leads b, and downward from the outer edge of the horizontal part h. It is formed into a crank shape in cross section having a vertical wall portion j that falls in the vertical direction and a stepped portion k that extends from the lower end of the vertical wall portion j to the outside in the horizontal direction again. On the other hand, the forming punch f is provided with a slide inner wall 1 which faces the vertical wall portion j through a predetermined clearance when it is moved downward, and a pressing lower surface m which also faces the horizontal portion h through a predetermined clearance. It is composed of left and right punch bodies n and m, and is substantially fixed to the ram p of the hydraulic press. Further, in the space between the left and right punch bodies n, n, the spring q constantly slides downward with respect to the punch bodies n, n while being urged downward, and
A pusher r is provided to fix the IC by pinching the base portions of both terminal leads b in cooperation with the horizontal portion h of the lower die portion d when the forming punch f moves downward. It was cut from the lead frame and made into each independent state
An IC semi-finished product or an IC semi-finished product in which each terminal lead b is separated so that it can be formed while being carried on a lead frame is the forming device c in which the ram p is in the upward movement position.
Is introduced onto the die e in a predetermined manner, and the forming punch f is moved downward, so that each terminal lead b
Is formed into a crank shape. That is, during the downward movement of the forming punch f, the pusher r first cooperates with the horizontal portions h and h of the fixed dies d and d to clamp the base portions of both the terminal leads b and fix the IC semi-finished product. , The corner s of the punch body n as shown in FIG.
Is bent while rubbing the upper surface of the terminal lead b from the base portion to the tip portion, and finally, as shown by the solid line in FIG. 7, is sandwiched in a crank shape by the lower die parts d, d and the punch bodies n, n. Pressed and molded.

[Problems to be Solved by the Invention]

As described above, in the conventional lead forming apparatus c, the forming punch f simply moves up and down, which causes the following problem in the terminal lead b bent while being scrubbed. That is, the terminal lead b is usually solder-plated before the forming process, but this solder-plating is scraped off by the corners s of the punch body of the forming punch f as described above, and thus the punch is formed. As shown in FIG. 7, the solder mass H adhering to the vicinity of the corner of the body n remains flat on the terminal lead b while being flatly crushed by the pinching action of the stepped portion k of the punch body f and the lower die part d. It will be nice. Then, the portion where the solder is scraped off remains as scratches on the outer surface of the terminal lead b, and the product quality is significantly deteriorated, and the flattened lump of solder as described above protrudes from the side edge of the terminal lead b. In some cases, this also contributes to the deterioration of product quality. In addition, as the number of pins increases as the integration of ICs progresses, each terminal lead b tends to become thinner and the distance between each terminal lead tends to become extremely small. In such a case, as described above, There is a possibility that the solder that is crushed and protrudes from the side edges of the terminal leads may come into contact with the adjacent terminal leads to cause a short circuit between the leads. The present invention solves the above-mentioned conventional problems, without deteriorating the surface quality of terminals after forming,
It is another object of the present invention to provide a lead forming apparatus capable of avoiding the above-described problems caused by scraping of solder during forming.

[Means for solving the problem]

In order to solve the above problem, the present invention takes the following technical measures. That is, the present invention is a lead forming apparatus that moves an upper forming punch downward with respect to a lower forming die to bend a terminal lead extending horizontally in a lateral direction of an electronic device package in a downward hook shape to support the forming punch. A pusher that is movable vertically only while being urged downward is provided with respect to the punch table that moves up and down, while the lower end of the forming punch can swing in the direction in which the terminal lead extends. At the same time, the pusher is provided with a cam for pressing the forming punch so that the lower end of the forming punch is forcibly moved toward the base end of the terminal lead when the punch base moves downward. To do.

[Action and effect]

The most characteristic point of the lead forming apparatus of the present invention is that the forming punch in the conventional apparatus of this type is fixed to the punch base and is configured to move integrally with the punch base only in the vertical direction. In contrast to the above, the lower end of the forming punch can be swung in the direction in which the terminal leads extend. Then, when the punch base starts to move downward, first, the pusher substantially abuts the forming die to stop the movement, and the electronic device having the terminal lead before forming is fixed between the pusher and the forming die. The forming punch moves downward, but this forming punch is
At the same time, the cam on the pusher forces it to move toward the proximal end of the terminal lead. That is, the forming punch has a function of bending the terminal lead while the tip of the forming punch moves downward and also moves in the base end direction of the terminal lead. Therefore, when the terminal lead is bent, the tip of the forming punch moves substantially in accordance with the bending locus of the terminal lead, and the rubbing of the surface of the terminal lead can be almost eliminated. By devising the shape of the cam, it is possible to make the movement locus of the tip of the forming punch into a bending locus of the terminal lead, that is, an arc shape centered on the bending portion. No more rubbing the surface of. As a result, the terminal lead after forming does not have a scratch like the conventional one, and the product quality is improved. Also, in the case where the terminal lead before forming is solder-plated, it is not scraped off by the forming punch.
There is no concern that the scraped-out solder mass will be crushed when the punch is pressed and this will cause a short between adjacent terminal leads. Further, since the cam for forcibly moving the forming punch in the direction of the base end of the terminal lead is located between the punch base and the forming die in terms of position, it is easy to dispose and the entire device becomes unnecessarily complicated. Nothing.

[Explanation of the embodiment]

Hereinafter, embodiments of the lead forming apparatus of the present invention will be specifically described with reference to the drawings. As shown in FIG. 1, the lead forming apparatus 1 of the present invention includes a forming die 2 supported by a base (not shown) and a forming punch 5, 5 vertically driven together with a punch base 4 by a ram 3 of a hydraulic press. It basically has and. The forming die 2 has almost the same structure as the conventional structure. That is, on both sides of the recessed portion 6 that accommodates the lower half of the resin package portion a of the electronic device, the horizontal portion 7 that supports the base portions of the both terminal leads b, and the horizontal portion 7
The vertical wall portion 8 that falls downward from the outer edge of the vertical wall 8 and the stepped portion 9 that extends from the lower end of the vertical wall portion 8 to the outside in the horizontal direction again.
It has a crank-shaped cross section. On the other hand, the pair of forming punches 5, 5 are formed in a plate shape having a predetermined width in the direction perpendicular to the paper surface of FIG.
The arcuate section 10 formed on the upper surface of the punch base 4 is abutted against the receiving section 11 having a concave arcuate section formed in the inner part of the accommodation hole 12 of the punch base 4 to swing about the center of the arc as a fulcrum. You can do it. This swing direction is the direction in which the terminal lead b of the electronic device extends. Further, both forming punches 5, 5 are constantly elastically biased in the outward opening direction by the compression coil springs 14, 14 held by the spring receiver 13 fixed between the forming punches 5, 5 in the accommodation hole 12. Has been done. As shown in FIG. 2, each of the forming punches 5, 5 has a support 19 in which projections 5a, 5a formed at both ends in the upper width direction are fixed in the accommodation hole 12.
Is engaged with and is prevented from falling. Below the punch table 4, a pusher plate 15 slides up and down with respect to the punch table 4 while the lower end of movement is defined by a vertical guide mechanism 16 and is urged downward by a spring 17. Supported as possible. The pusher plate 15 is formed with a through hole 18 for vertically penetrating the pair of forming punches 5, 5, and a portion sandwiched between the forming punches 5, 5 is formed when the forming punch 5 moves downward. A pusher 21 is formed which cooperates with the horizontal portions 7 and 7 of the die to clamp and fix the base portion of the terminal lead b of the electronic device. On the outer surface of each forming punch 5, 5, stepped cam follower portions 5b, 5b formed by reducing the thickness of the lower tip portion with respect to the upper base portion are formed, while the transparent plate of the pressure plate 15 is formed. On the inner surface of the hole 18,
When the forming punches 5 and 5 are moving downward, the cam follower part 5
A cam that presses b and 5b to force the forming punches 5 and 5 inward, that is, toward the base end of the terminal lead b.
20,20 have been planted. The vertical position of the cams 20, 20 is set so as to be located immediately below the cam follower parts 5b, 5b as shown in FIG. 1 when the pusher plate 15 is at the lower end of relative movement with respect to the punch base 4. Has been done. Further, the relationship between the pressure plate 15 or pusher 21 at the lower end of the relative movement with respect to the punch base 4 and the lower end positions of the forming punches 5, 5 is as follows.
As shown in FIG. 1, the punch base 4 moves downward and the pusher 21
The lower ends of the forming punches 5 and 5 are set to have substantially the same height so that the tips of the forming punches 5, 5 come into contact with the upper surfaces of the tip portions of the terminal leads b at the same time. Therefore, the punch table 4 moves downward, and the pusher 21 moving downward together with it lowers the horizontal portion 7 of the die 2.
At the same time as contacting the upper terminal lead b, pusher plate
15 or the relative downward movement of the forming punches 5,5 to the cams 20,20 begins. When the forming punches 5,5 start moving downward relative to the cams 20,20, the cams 20,20 press the cam followers 5b, 5b to force the forming punches 5,5 to approach each other, that is, the terminals. The lead b is rotated in the proximal direction. The horizontal positional relationship between the forming punches 5 and 5 with respect to the forming die 2 is such that before the forming action, that is, before the forced movement by the cams 20 and 20 and the cam followers 5b and 5b, the inner corners 5c and 5c are finally set. It is possible to contact the portion of the terminal lead b bent in a crank shape corresponding to the second bent portion b _2, and after the forming action, that is, after the forced movement by the cams 20, 20 and the cam follower portions 5b, 5b. The inner corner portions 5c, 5c are set to cooperate with the standing wall portion 8 or the step-down portion 9 of the forming die 2 so that the terminal lead b can be clamped while being deformed into a crank shape. In the above configuration, when the punch base 4 is in the upward movement state, the electronic device before the terminal lead forming is placed on the forming die 2 and the terminal lead b is placed on the horizontal portion 7 of the die by the shooter (not shown). Introduced at the same time. It may be introduced cut off from the lead frame or it may be introduced while still carried on the lead frame. Then, when the punch base 4 moves downward, the forming punches 5, 5 and the pusher plate 15 integrally move downward. Eventually, the pusher 21 of the pusher plate 15 clamps the terminal lead b on the horizontal portion 7 of the die and stops. At this time, as shown by an imaginary line in FIG. 3, the tips of the forming punches 5, 5 are in contact with the portion of the terminal lead b corresponding to the second bent portion b ₂ . Subsequently, the punch base 4 further moves downward, but since the downward movement of the pusher plate 15 has stopped as described above, the forming punch 5,
5 moves down relative to the pusher plate 15. At this time, the cams 20, 20 supported by the pusher plate 15
And the cam follower portions 5b, 5b of the forming punches 5, 5 cooperate with each other to forcefully rotate the forming punches 5, 5, so that the tips of the forming punches 5, 5 are shown by the solid lines in FIG. , And the terminal lead b is bent into a crank shape between the die 2 and the die 2 and clamped. What is important here is that, in the present invention, the forming punches 5, 5 bend the terminal leads b while moving not only vertically but also horizontally. In the above-mentioned example, the initial contact position of the forming punch 5, 5 with respect to the terminal lead b is the second bending position b ₂ . Therefore, forming punch 5,
The inner corners 5c, 5c of 5 and the surface of the terminal lead b hardly move relatively during the forming operation, so that the forming punches 5, 5 hardly scratch the surface of the terminal lead b. Regarding this point, considering the shapes of the cams 20 and 20 and the cam follower portions 5b and 5b, the movement loci of the inner corner portions 5c and 5c of the forming punches 5 and 5 are determined by the upper end of the standing wall portion 8 of the die 2, that is, the crank shape. It is also possible to set it in an arc shape centered on the first bending position b ₁ of the terminal lead b that can be bent in the vertical direction. Then, the relative movement of the corners 5c, 5c of the forming punch 5, 5 and the terminal lead b during the forming action is completely eliminated. Therefore, according to the lead forming apparatus of the present invention, since the forming punch that acts to bend the terminal lead does not rub the surface of the terminal lead, no scratch is left on the surface of the terminal lead of the product and the product quality is high. improves. Further, for the same reason, the solder on the terminal leads is scraped off by the forming punch and is crushed and crushed, so that there is no problem of deterioration of product quality and short-circuit between leads. Of course, the scope of the present invention is not limited to the above embodiments. For example, although the illustrated example is configured for forming a terminal lead in a so-called mini-flat type package, in a so-called quad flat type package in which the terminal leads protrude in a comb shape from the four sides of the rectangular resin package portion. It can also be configured for forming terminal leads. In this case, it is preferable that four forming punches, which are provided so as to face each other in the embodiment, are provided corresponding to the four sides, and the peripheral configuration is adapted to this. Further, although the above-described embodiment is premised on bending the terminal lead b in a crank shape corresponding to the flat type package, the present invention is also applicable to a case where only one bending portion is provided and the tip is bent downward in a hook shape. Can be applied.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG.
FIG. 3 is a side view of the forming punch in the figure, FIG. 3 is an operation explanatory view, FIG. 4 is a perspective view of a part of an electronic device in which the terminal leads are bent by the lead forming device of the present invention, and FIG. FIG. 6 is a cross-sectional view of the conventional example, and FIG. 7 is an operation explanatory view of the conventional example. 1 ... Lead forming device, 2 ... Forming die, 5 ... Forming punch, 20 ... Cam, 21 ... Pusher, b ... Terminal lead.

Claims (1)

(57) [Claims] 1. A lead forming apparatus in which an upper forming punch is moved downward with respect to a lower forming die, and a terminal lead extending horizontally in a lateral direction of an electronic device package is bent downward in a hook shape to support the forming punch. A pusher is provided that is capable of relative movement only in the vertical direction while being urged in the downward direction with respect to the vertically movable punch base, while the lower end of the forming punch is swingable in the direction in which the terminal lead extends. At the same time, a cam for pressing the forming punch is provided at an appropriate portion of the pusher so that the lower end of the forming punch is forcibly moved toward the base end of the terminal lead when the punch base moves downward. , Lead forming equipment.