JPH01157717A - Lead forming device - Google Patents

Abstract

PURPOSE:To prevent a defect from occurring caused by scraping away of solder and to improve the product quality by providing a cam to compress a forming pump, on a pusher, so that the lower end of the forming punch is moved forcedly in the direction of the base end of a terminal lead when the punch moves down. CONSTITUTION:Soon after the punch base moves down, the pusher 21 of the pusher plate 15 grips a terminal lead (b) on the horizontal part of a die and stops. At this time the point of the forming punch 5 is brought into contact with a position corresponding to a 2nd folded part (b2) of the lead (b). Then, the punch base continues to move down further, but, since the pusher plate 15 stops moving down, the punch 5 moves down relatively to the pusher plate 15 thereafter. At this time, a cam 20 supported by the pusher plate 15 and a cam follower part 5b of the punch 5 cooperate with each other to revolve the punch forcedly. As a result, the point part of the punch 5 moves and the terminal lead (b) is folded between the die 2 and the punch in a crank form and compressed.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a lead forming device that bends terminal leads of electronic components such as ICs into a predetermined shape. [Conventional technology]

In an IC having a so-called flat package as shown in FIGS. 4 and 5, terminal leads b...
is bent into a crank shape. This kind of bending of the terminal lead b... is carried out in a series of steps for this type of electronic device in which work is performed on the lead frame, including the wire bonding process, wire bonding process, resin molding process, solder plating process, etc. In the manufacturing process,
Adjacent to or simultaneously with the dam bar cutting step or lead cutting step subsequent to the resin molding step or solder plating step, or at the same time, it was carried out using a forming device as in the conventional method. That is, as shown in FIG. 6, the conventional forming device c includes a fixed die e having left and right lower mold parts d, d;
A forming punch f that is moved up and down by a hydraulic press or the like is provided above the fixed die e. The lower mold parts d, d are arranged on both sides of the recessed part g that accommodates the lower half of the resin package part a, and the two terminal leads b
A cross-sectional crank having a horizontal part that supports the base of the horizontal part, a standing wall part j that falls downward from the outer edge of this horizontal part, and a stepped part k that extends outward from the lower end of this standing wall part j in a substantially horizontal direction. It is formed in the shape of On the other hand, when the forming punch f moves to the lowest position, it forms a slide inner wall l that faces the die wall j with a predetermined gap in between, and a pressing lower surface m that also faces the horizontal part with a predetermined gap in between. It consists of left and right punch bodies n, n, which are substantially fixed to the ram p of the hydraulic press. In addition, in the space between the left and right punch bodies n, n, there is a hole that slides vertically relative to the punch bodies n, while being constantly urged downward by a spring q, and when the forming punch f moves downward. A pusher r is provided which cooperates with the horizontal portion of the lower mold part d to clamp the bases of both terminal leads b to fix the IC. I cut from the lead frame into each independent state
The C semi-finished product or the IC semi-finished product in which each terminal lead b is separated so as to be formed while being supported on a lead frame is placed on the guide e of the forming device C in which the ram p is in the upward movement position in a predetermined manner. By moving the forming punch f downward, each terminal lead b is formed into a crank shape. That is, during the downward movement of the forming punch f, the pusher r cooperates with the fixing die d, the horizontal part of d, and h to pinch the bases of both terminal leads b to fix the IC semi-finished product, and then , as shown in an enlarged view in FIG. 7, the corner S of the punch body n rubs and bends the upper surface of the terminal lead b from the base to the tip, and finally, as shown in solid lines in FIG. It is pressed and molded into a crank shape by the mold parts d, d and the punch bodies n, n.

[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 with the terminal lead b, which is bent while being rubbed. That is, although the terminal lead b is normally solder-plated before the forming process, this solder-plating is scraped off by the corner 3 of the punch body of the forming punch f as described above, and thus the punch body n As shown in Figure 7, the solder lump H attached near the corner of the punch body

[Then, it remains on the terminal lead b while being flattened by the pinching action of the step-down part k of the lower mold part d. If this happens, the part where the solder has been rubbed off remains as a scratch mark on the outer surface of the terminal lead b, which significantly reduces the quality of the product, and the flattened lump of solder protrudes from the side edge of the terminal lead b as described above. This may also be a cause of deterioration of product quality. Furthermore, as the integration of tC progresses and the number of pins increases, each terminal lead b becomes thinner and the distance between each terminal lead tends to become extremely small. There is also a risk that the crushed solder protruding from the side edge of the terminal lead will come into contact with an adjacent terminal lead, causing a short circuit between the leads. This invention solves the above-mentioned conventional problems, does not degrade the surface quality of the terminal after forming (and prevents the above-mentioned problems caused by solder being rubbed off during forming). It is an object of the present invention to provide a lead forming device that can avoid the above problem. [Means for solving the problem] In order to solve the above problem, the present invention takes the following technical means. That is, The present invention provides a lead forming device that moves an upper forming punch downward relative to a lower forming die and bends a terminal lead extending horizontally to the side of an electronic device package into a downward hook shape. The forming punch is provided with a pusher that can move relative to the moving punch stand only in the vertical direction while urging it downward, and the forming punch is configured such that its lower end is swingable in the direction in which the terminal lead extends. The present invention is characterized in that a cam is provided at an appropriate portion of the pusher to press the forming punch so that the lower end of the forming punch forcibly moves toward the proximal end of the terminal lead when the punch base moves downward. [Operations and Effects] The most distinctive feature of the lead forming device of the present invention is that the forming punch in conventional devices of this type is fixed to the punch stand, and is integrated with the punch stand only in the vertical direction. The lower end of the forming punch is configured to be able to swing in the direction in which the terminal lead extends, whereas the former was configured to move.When the punch base begins to move downward, First, the pusher substantially contacts the forming die to stop its movement, and fixes the electronic device with the terminal lead before forming between it and the forming die.Subsequently, the forming punch moves downward; At the same time, the forming punch is forcibly moved toward the proximal end of the terminal lead by the cam on the pusher.In other words, the tip of the forming punch moves downward and also moves toward the proximal end of the terminal lead. Therefore, when bending the terminal lead, the tip of the forming punch moves almost in accordance with the bending trajectory of the terminal lead, and it is possible to almost eliminate rubbing against the surface of the terminal lead. By devising the shape of the cam, it is possible to make the movement locus of the tip of the forming punch the bending locus of the terminal lead, that is, an arc shape centered on the bending part. At times, there is no need to rub the surface of the terminal lead. As a result of the above, the terminal leads after forming do not suffer from scratches as in the conventional case, and the quality of the product is improved. In addition, even if the terminal lead is solder-plated before forming, it will not be rubbed off by the forming punch, unlike conventional methods.
There is no fear that the scraped solder mass will be crushed during crimping with a punch, causing a short circuit between adjacent terminal leads. In addition, the cam for forcibly moving the forming punch toward the proximal end of the terminal lead is located between the punch base and the forming die, so it can be easily placed.
There is no need to make the entire device unnecessarily complicated.

[Explanation of Examples]

Embodiments of the lead forming apparatus of the present invention will be specifically described below 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 that is driven in the vertical direction together with a punch stand 4 by a ram 3 of a hydraulic press. It basically has the following. The forming die 2 has almost the same structure as the conventional one, that is, the forming die 2 has a horizontal structure that supports the bases of both terminal leads b on both sides of the recessed part 6 that accommodates the lower half of the resin puff cage part a of the electronic device. part 7, a standing wall part 8 that falls downward from the outer edge of this horizontal part 7, and this standing wall part 8.
a stepped portion 9 extending outward again in a substantially horizontal direction from the lower end;
It is shaped like a crank in 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 cross-section arc part 10 formed on the upper surface is a concave arc cross-section shaped receiver part 1) formed in the inner part of the accommodation hole 12 of the punch base 4.
By being placed against it, it is possible to swing around the center of the circular arc as a fulcrum. This swing direction is
This is the direction in which the terminal lead b of the electronic device extends. Further, both forming punches 5, 5 are always elastically biased in the outward opening direction by a compression coil spring 14.14 held in a spring receiver 13 fixed between both forming punches 5.5 in the accommodation hole 12. has been done. In addition, the second
As shown in the figure, projections 5a, 5a formed at both ends in the upper width direction of each forming punch 5.5 engage with a support 19 fixed in the accommodation hole 12, and are prevented from falling. A pusher plate 15 is disposed below the punch base 4, with its lower end of movement being defined by a vertical guide mechanism 16, and being biased downward by a spring 17.
It is supported so as to be slidable in the vertical direction with respect to the punch stand 4. This pusher plate 15 has a through hole 18 through which the pair of forming punches 5.5 pass in the vertical direction.
is formed, and both forming punches 5.5
In the area sandwiched between
A pusher 21 is formed to clamp and fix the base of the holder. Step-shaped cam follower parts 5b, 5b formed by reducing the thickness of the lower tip part with respect to the upper base part are formed on the outer surface of each forming punch 5, 5,
The cam follower portion 5b is formed on the inner surface of the through hole 1B in the pusher plate 15 when the forming punch 5.5 moves downward. A cam 20.20 is installed for pressing the forming punch 5.5 inward, that is, toward the proximal end of the terminal lead b. The vertical position of the cam 20.20 is such that when the pusher plate 15 is at the lower end of relative movement with respect to the punch base 4, it is located immediately below the cam follower parts 5b, 5b as shown in FIG. It is set. Also, punch stand 4
The relationship between the pusher plate 15 or pusher 21 at the lower end of relative movement to the lower end of the forming punch 5.5 is as shown in FIG. The lower ends of the forming punches 5, 5 are set at substantially the same height so that when they contact the upper surface of the base, the tips of the forming punches 5, 5 simultaneously contact the upper surface of the tip of the terminal lead b. Therefore, the punch base 4 moves downward, and the pusher 21 moves downward together with the punch base 4.
touches the terminal lead b on the horizontal portion 7 of the die 2, and at the same time the pusher plate 15 or cam 20. The forming punches 5, 5 begin to move downward relative to -20. When the forming punch 5.5 starts to move downward relative to the cam 20.20, the cam 20.20 moves toward the cam follower 5b.
, 5b to forcibly rotate the forming punches 5.5 toward each other, that is, toward the proximal end of the terminal lead b. The horizontal positional relationship of the forming punch 5.5 with respect to the forming die 2 is such that before the forming action, that is, before forced movement by the cam 20.20 and the cam follower parts 5b, 5b, the inner corner parts 5c, 5c are finally It is possible to contact a portion corresponding to the second bent portion b° of the terminal lead b bent into a crank shape, and after the forming action, that is, the cam 20.
20 and the cam follower parts 5b, 5b, the inner corner parts 5c, 5c are moved by the forming die 2.
Terminal lead b
It is set so that it can be compressed without deforming it into a crank shape. In the above configuration, when the punch base 4 is in the upward movement state, the electronic device before terminal lead forming is placed on the forming die 2 by a shooter (not shown) so that the terminal lead b thereof is placed on the horizontal part 7 of the die. It is introduced in such a manner. It may be introduced detached from the lead frame or still supported on the lead frame. When the punch stand 4 moves downward, the forming punch 5.5 and the pusher plate 15 move downward together. Eventually, the pusher 21 of the pusher plate 15 pinches the terminal lead b on the horizontal portion 7 of the die and stops. At this time, as shown by the imaginary line in FIG. 3, the tip of the forming punch 5.5 is in contact with a portion of the terminal lead b that corresponds to the second bent portion b2. 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 punches 5, 5 move downward relative to the pusher plate 15 from then on. At this time, the cam 20.20 supported by the pusher plate 15 and the cam follower parts 5b, 5b of the forming punch 5.5 cooperate to forcibly rotate the forming punch 5.5. The tip of the terminal lead b moves as shown by the solid line in FIG. What is important here is that in the present invention, the forming punch 5.5 not only moves up and down, but also moves in the horizontal direction while bending the terminal lead b. In the above example, the initial contact position of the forming punches 5, 5 with respect to the terminal lead b is the second bent position thereof. Therefore, the inner corner portions 5c, 5c of the forming punches 5. The forming punch 5.5 hardly moves relative to the surface of the terminal lead b during the forming operation, so the forming punch 5.5 hardly ever rubs the surface of the terminal lead b. Cam 20 in this regard
．． 20 and the cam follower section 5b. Considering the shape of the forming punch 5b, the movement locus of the inner corner parts 5c, 5c of the forming punch 5.5 is set at the upper end of the vertical wall part 8 of the die 2, that is, the first bending position of the terminal lead b bent into a crank shape. It can also be set in an arc shape with the center at . Then, forming punch 5.5
The above-mentioned corner portion 5c. There is no relative movement between 5C and terminal lead b during the forming action. Therefore, according to the lead forming device of the present invention, the forming punch that bends the terminal lead does not rub the surface of the terminal lead, so no scratches are left on the surface of the terminal lead of the product, and the quality of the product is improved. improves. Furthermore, for the same reason, problems such as deterioration of product quality and short-circuiting between the leads due to solder on the terminal leads being scraped off by the forming punch and crushed are eliminated. Of course, the scope of the present invention is not limited to the above-described embodiments. For example, the illustrated example is configured for forming terminal leads in a so-called mini-flat package; It can also be configured for forming terminal leads in a so-called quad flat package in which the terminal leads protrude in a comb shape from the four sides of the part. In this case, it is preferable to provide four forming punches corresponding to each other on each side of the pair of forming punches provided in the embodiment, and to adjust the peripheral configuration accordingly. Furthermore, although the above-described embodiment is based on the assumption that the terminal lead b is bent into a crank shape to correspond to a flat package, the present invention can also be applied to a case where the bending portion is simply bent at one point and the tip is bent downward into a hook shape. can be applied.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG.
FIG. 3 is a side view of the forming punch in the figure, FIG. 3 is an explanatory diagram of the operation, FIG. FIG. 6 is a sectional view of the conventional example, and FIG. 7 is an explanatory diagram of the operation of the conventional example. DESCRIPTION OF SYMBOLS 1... Lead forming device, 2... Forming die, 5... Forming punch, 20... Cam, 21... Pusher, b... Terminal lead.

Claims (1)

[Claims] (1) In a lead forming device that moves the upper forming punch downward relative to the lower forming die and bends the terminal lead extending horizontally to the side of the electronic device package into a downward hook shape, the forming punch is supported and moved up and down. A pusher is provided with respect to the punch stand that is biased downward and is movable only in the vertical direction, and the lower end of the forming punch is swingable in the direction in which the terminal lead extends; A lead characterized in that a cam is provided at an appropriate part of the pusher to press the forming punch so that the lower end of the forming punch forcibly moves toward the proximal end of the terminal lead when the punch base moves downward. Forming equipment.