JPH09321204A - Lead forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent positional shift of molds and a lead and to form a plate layer, which is soft and even easily ground but is not peeled off, on a lead surface, by horizontally moving a first mold to a lead base side in a state where the first mold and a second mold hold a floating end of the lead between them, and at the same time, projecting the first mold toward the second mold side. SOLUTION: First and second molds 13 and 14 hold the tip end of a lead 3 between them, and in this status, the first mold 13 is moved to a lower pad 8 side and at the same time raised. The movement as the combination of horizontal movement and elevation may be a linear movement, however, preferably, the movement may trace a circular arc which does not loosen the lead or if loosens, minimize the looseness. The lead 3 begins to bend at a portion held by pads 8 and 12 and a portion held by the first and second molds 13 and 14. The deforming portions of the lead 3 do not cause positional shifts relative to the molds. As the intermediate portion of the lead does not come in contact with the molds, the plate layer covering the lead 3 is not peeled off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technical field related to an apparatus for molding leads of electronic components with leads.

[0002]

2. Description of the Related Art An example of a resin mold type electronic component is shown in FIG. In the figure, 1 is an electronic component body, for example, an island for mounting a semiconductor pellet 2, 3 is a set of a plurality of leads, one end of which is arranged in the vicinity of the island 1 and the middle part to the other end of which are arranged in parallel. Wires 5 that electrically connect electrodes (not shown) on the main body 2 and the inner ends of the leads 3 to each other indicate a resin exterior portion that covers the main part including the electronic component main body 1. The electronic component 6 is manufactured by using a lead frame in which the island 1 and a set of a plurality of leads 3 are integrally molded in the frame by pressing or etching a thin metal plate. That is, the electronic component body 2 is fixed to the island 1 using solder or a conductive adhesive, the electrodes on the electronic component body 2 and the leads 3 are connected by the wires 4, and between the cavities of the resin molding die, Position the area surrounding the island 1 including the tip of the lead on the lead frame,
A fluidized resin is injected into the cavity to cover the electronic component body 2 with the resin, and unnecessary portions of the lead frame exposed from the resin exterior portion 5 of the lead frame are cut and removed, and the middle portion of the lead 3 is removed. By bending and forming, the electronic component 6 shown in FIG. 3 is obtained. In order to improve the mountability of the electronic component 6 on the printed wiring board, the condition that the intervals between the bent leads 3 are constant and that the surfaces formed by the free ends of the leads 3 are on the same plane. Must be satisfied. For example, in the case of a power IC having a lead width of 0.7 mm and a lead interval of 2.5 mm, it is required to suppress the positional deviation of the lead tips within 0.3 mm. FIG. 4 shows an example of an apparatus for molding the leads of the electronic component 6. In the figure, 7 is a pedestal that supports the exterior part 5 of the electronic component 6, 8 is an outer periphery of the pedestal 7, and the leads 3 led out from the side wall of the exterior part 5
The lower pad supporting the lower surface of the lower pad and the lower die 9 arranged on the outer periphery of the lower pad 8 and moving up and down. The upper end to the inner periphery of the lower die are processed according to the shape of the lead 3. 10 is an upper pad that vertically moves to face the lower pad 8 and holds the base of the lead 3 therebetween, and 11 is arranged on the outer periphery of the upper pad 10 and vertically moves to move the free end of the lead 3 together with the lower die 9. An upper mold to be clamped, and it is processed according to the shape of the lead to be finally molded. The distance between the upper and lower molds 9 and 11 is set in consideration of the thickness of the lead 3. This device has an electronic component 6 on a cradle 7.
The base of the lead 3 is sandwiched between the upper and lower pads 8 and 10, the upper die 11 is lowered to bring the lower end thereof close to the lead 3, and the lower die 9 is raised. Type 9
Of the upper and lower pads 8 and 10 bends around the sandwiching portions of the upper and lower pads 8 and 10, and the lead 3 is deformed as the lower mold 9 rises, and finally the upper and lower molds 9,
The lead 3 is molded by 11 and the electronic component 6 shown in FIG.
Is obtained.

[0003]

By the way, in order to improve the solderability and the mountability, the leads 3 are subjected to solder plating which is softer than the base of the leads 3. When the leads 3 are formed by immersing the solder plating in the molten solder, the surface of the plating layer is curved due to surface tension,
The lead 3 has a different thickness in the width direction. Such a lead 3
4 is molded by the lead molding apparatus shown in FIG. 4, the mold 9 contacts the position A (origin) shown on the lead 3 before the molding, and contacts the position B shown on the lead 3 when the molding is completed. Since the origin A is located at the position C shown in the figure after molding, the surface of the lead 3 is rubbed by the mold 9 when the lead 3 is molded from the straight state to the bent state between C and B in the figure, and the plating layer formed on the surface of the lead becomes the mold. Are scraped off by the tool and concentrated on the mold 9 corresponding to the position A in the figure. Further, the plating layer on the free end portion of the back surface of the lead is also scraped by the upper mold 11. Since the plating layer is formed such that the center of the lead surface in the width direction swells, the plating layer in this portion is mainly shaved and accumulated in the portion of the die 9 that comes into contact with the lead 3, and the die 9 on the surface of the lead 3 relative to each other. Prevent the progress of. The plated material scraped in this way is pushed into the thin plated portions on both sides in the lead width direction by the progress of the die 9, but it is not always pushed equally to both sides, and if it is biased to one side, the lead 3 is tilted. There was a problem that force was generated and lead intervals were uneven. Therefore, a groove for accommodating the leads 3 one by one is formed on the surface of the die 9 to form the leads 3
The bending of the lead is also regulated. However, if the elastic force received during molding remains on the lead 3, even if the gap is regulated in the groove, the lead taken out from the groove releases the elastic force and the gap is reduced. Could not be prevented from becoming irregular. Although the base of the lead 3 is sandwiched by the pads 8 and 10, tension acts on the lead when the lead is deformed by the mold 9, and this tension acts on the lead 3 and the wire 4 in the exterior portion 5.
There was a case where the wire was cut to the connection part and the wire was broken to impair the electrical connection. Further, if the plating material scraped by the mold 9 remains on the leads 3, it will be peeled off when mounting the electronic component 6 on a printed wiring board or the like to become a foreign substance, which may cause a short circuit or insulation failure of the electronic circuit device. Therefore, after lead molding, it is necessary to melt the scraped plating material by a hydrogen reducing flame to melt and integrate it into the plating layer, or to mechanically remove it using a brush or the like, which increases the number of work steps. There was a problem. Further, the shape of the facing surface of the molds 9 and 11 is determined by the molding shape of the lead 3, but this shape cannot be changed, and the molds 9 and 11 are prepared corresponding to the model of the electronic component 6, Each time it was changed, it had to be replaced, and the work was complicated.

[0004]

SUMMARY OF THE INVENTION The present invention has been proposed for the purpose of solving the above-mentioned problems, and an exterior portion is formed by electrically connecting an electronic component body and a lead and exteriorly covering a main portion including the electronic component body. A pair of pads sandwiching both sides of the lead base portion of the electronic component in which the lead is led out from the side wall, and an end portion abuts on an intermediate portion of the lead extending outward from the pad, and one pad is separated from the outer side position of the side wall. A first mold that is located close to the pad and protrudes toward the other pad to bend the lead from the pad portion; and a lead free end portion that is arranged so as to face the first mold and is pressed against the first mold. Provided is a lead forming apparatus including a second mold for bending by bending.

[0005]

Embodiments of the present invention will be described below. In the apparatus according to the present invention, the first die is horizontally moved to the lead base side and is simultaneously protruded to the second die side with the lead free end being sandwiched between the first and second dies. Since the lead can be molded while maintaining the relative positions of the lead middle part and the first and second molds, there is no misalignment between the mold and the lead, and a soft and easily scraped plating layer is formed on the lead surface. However, there is no need to worry about peeling off the plating layer. Control of horizontal movement and vertical movement of the first and second molds can be set according to the lead forming shape, and various lead shapes can be supported. Further, the first mold can be composed of a rotating body that rotates around a rotation axis along the vicinity of the lead base. As a result, the first die becomes an arc movement that is a combination of horizontal movement and vertical movement about the rotation axis, and the rotation axis is brought close to the bent portion of the lead, so that the relative position of the die and the lead is obtained. The gap can be set small. In this case, prior to the operation of the first die, the lead free end portion is bent by the second die to press the lead free end portion against the first die. Further, by forming a groove for accommodating the lead on the surface of the first mold that abuts the lead, the position of the lead during bending can be regulated, and by pressing the lead without any positional deviation from the lead, The plating layer on the surface of the lead is locally pressed so that the thickness of the plating layer in this part can be made uniform in the width direction of the lead, so the force in the twisting direction does not act on the lead, and the formed leads maintain their intervals. It can be taken out from the groove in the state. Further, the lead can be guided from the lead base portion toward the lead free end before the lead is sandwiched by the first and second molds.

[0006]

FIG. 1 shows an embodiment of the present invention.
In the figure, the same parts as those in FIGS. 3 and 4 are designated by the same reference numerals, and the duplicated description will be omitted. In the figure, 12 is the lower pad 8
The outer surface of the upper pad faces a part of the molding surface, the lower end abuts the base of the lead 3, and the lead 3 is pressed against and clamped by the lower pad 8. 13 is a lower mold (first mold) which is arranged outside the lower pad 8 so as to be spaced apart from the lower pad 8 and move up and down to move up and down in an oblique direction shown by a dotted arrow in the figure. The inner side wall is formed along the outer side wall of the upper pad 12. 14 moves up and down above the lower mold 13 to move the outer end of the lead 3 to the lower mold 1.
The upper die (second die) which is pressed against the upper end surface of 3 to maintain this state and interlocks with the lower die 13 is attached to the flat upper end surface adjacent to the curved surface of the first die 13. The free end of the lead 3 is pressed and clamped. The operation of this device will be described below. First, the electronic component 6 is placed on the pedestal 7, and the base of the lead 3 is sandwiched between the pair of upper and lower pads 8 and 12. Next, lead 3
The tip of the mold is clamped by the first and second molds 13 and 14, and the first mold 13 is moved to the lower pad 8 side and raised while maintaining the clamped state. The movement that combines the horizontal movement and the vertical movement may be a linear movement, but if the lead is loosened in the middle of the movement, undesired stress is applied to the portion sandwiching the lead, so that the lead is not loosened. It is preferable to make an arc motion that can minimize the influence even if it occurs, because the bent portion of the lead 3 is made clear. As a result, the lead 3 begins to bend from the portion sandwiched between the pads 8 and 12 and the portion sandwiched between the first and second molds 13 and 14, and the deformed portion of the lead 3 is relatively moved between the die and the mold. Since there is no positional deviation and the middle part of the lead does not come into contact with the mold, there is no fear that the plating layer coated on the lead 3 will peel off. Finally, the middle portion of the lead 3 is connected to the upper pad 1
It is sandwiched between 2 and the lower mold 13, and the molding is completed as shown by the dotted line in the figure. In the lead forming by this device, tension is not applied to the lead when the lead is bent, so that the lead after the bend forming does not retain the force for restoring the state before the bend forming and the formability is good. Further, since no tension acts on the leads, the airtightness between the leads 3 and the resin 5 is maintained, and the electrical connection between the leads 3 and the wires 4 in the exterior portion 5 is not damaged. By using this device, the plating material coated on the leads 3 does not peel off, so that no foreign matter is generated by the flaking pieces, and it is possible to prevent a short circuit or insulation failure of the electronic circuit device due to the foreign matter. Further, the work for removing the foreign matter is not required, and the cost of the electronic component can be reduced. Also, the first and second molds 13, 1
Since the lead bending position and angle can be adjusted by controlling the lead holding position of No. 4, a single piece of equipment can support many models. FIG. 2 shows another embodiment of the present invention. In the electronic component of the illustrated example, the lead 3 is led out from one side wall of the resin exterior part 5. In the figure, what is different from the device in FIG. 1 is a first mold 15 and a second mold 16, and the rest is basically the same as the device in FIG. The above differences will be described in detail. The first mold 15 has a rotating shaft 15a arranged along the lower pad 8 outside the upper end of the lower pad 8 and at least a portion to be bent on the lower surface of the middle part of the lead 3 which rotates around the rotating shaft 15a. Pressing part 15 for pressing
b, and an inclined surface portion 15c formed on the end surface adjacent to the pressing portion 15b. In the second mold 16, the lead 3 is in a straight line state, and the pressing part 15b and the inclined surface part 15c of the first mold 15 are used.
And a flat surface portion 16a and an inclined surface portion 16b that face each other. The operation of this device will be described below. First, as shown in FIG. 1, the first mold 15 is placed in a horizontal state, and the second mold 1
In a state where 6 is raised, the resin exterior portion 5 of the electronic component 6 is placed on the pedestal 7, and the base portions of the leads 3 are clamped and positioned by the upper and lower pads 8 and 12. Next, the second die 16 is lowered to sandwich the free end portion of the lead 3 between the inclined surface portions 15c and 16b of the first and second die 15 and 16, respectively, and the free end side of the lead 3 is held. Bend the middle part. Then, the second mold 16 is raised and the first mold 15 is rotated around its rotation axis 15a to bend the lead 3 from the portion sandwiched by the upper and lower pads 8 and 12 on the lead base side and press it. The lower surface of the lead is pressed by the portion 15b and is rotated until the intermediate portion or the free end portion of the lead 3 becomes substantially parallel to the lead base portion. This completes the molding of the lead 3, but the lead free end portion in the state of being pushed up by the first mold 15 is moved to the second mold 1
It is possible to reliably bend and form the bent portion on the lead free end side by being sandwiched by the flat portions 16a. In this device, since the middle part of the lead 3 is rotated by the first die 15 in an arcuate state, the slack of the lead during the molding is small, and even if the slack is generated, the lead 3 does not loosen during bending. Since the ends are not restrained, there is no deformation of the leads. By arranging the rotating shaft 15a of the first mold 15 close to the bent portion of the lead 3 and preferably arranging the rotating shaft 15a at the bent position of the lead 3, the slack of the lead 3 during rotation can be minimized. The deformation can be prevented. In each of the embodiments described in FIGS. 1 and 2, the first
A groove for accommodating the leads 3 one by one and separating the adjacent leads 3 may be formed on the surface of the molds 13, 15 facing the leads 3. As a result, the lead is separated before the lead is bent and molded, and is sandwiched by the first and second molds in that state, and there is no relative displacement between the sandwiched portion and the lead 3.
Since even if the positional deviation occurs, it is small, so the plating material covered by the leads 3 is spread to both sides at the sandwiching portion, and no force that bends the leads 3 is generated. I can keep it. The present invention is not limited to the above-described embodiment, and for example, the pedestal 7 and the lower pad 8 are separately provided, but they may be integrally formed. Further, the present invention can be applied to electronic components having any lead arrangement, regardless of the type of the electronic component body, as long as the electronic components are leads derived from the side wall of the exterior part.

[0007]

As described above, according to the present invention, it is possible to realize a lead forming apparatus that does not generate foreign matter without making lead intervals uneven by bending forming.

[Brief description of drawings]

FIG. 1 is a front sectional view of a lead forming apparatus according to the present invention.

FIG. 2 is a perspective view of an essential part showing another embodiment of the present invention.

FIG. 3 is a front sectional view of a resin mold type electronic component.

FIG. 4 is a front sectional view showing an example of a conventional lead forming apparatus.

[Explanation of symbols]

 2 electronic component main body 3 lead 5 exterior part 6 electronic component 8 pad 10 pad 13 first mold 14 second mold 15 first mold (rotating body) 15a rotating shaft

Claims (3)

[Claims] 1. A pair of pads for electrically connecting an electronic component main body and a lead, covering a main part including the electronic component main body, and sandwiching both sides of a lead base of an electronic component from which the lead is led out from a side wall of an exterior portion. An end portion abuts on an intermediate portion of the lead extending outward from the pad, and the lead bends from the pad portion by projecting to the other pad side while being close to this pad from the separated position on the outer side wall of one pad. A lead forming apparatus comprising: a first die; and a second die that is arranged to face the first die and presses the lead free end portion against the first die to bend the die. . 2. A first mold for pressing an intermediate portion of a lead,
A rotary body having a rotary shaft extending along the vicinity of a lead base portion sandwiched by a pair of pads.
The lead forming apparatus described in. 3. The lead forming apparatus according to claim 1, wherein a groove for separating each lead is formed in at least one of the first mold and the second mold.