JPH04299559A - Bending method of lead - Google Patents

Abstract

PURPOSE:To realize highly precise bending without damaging a lead and peeling a plated film formed on the lead. CONSTITUTION:In a lead bending method for bending a lead 10 in a J-shape, the tip of the lead 10 is bent in a shape approximate to a final curling shape, in a plurality of initial steps out of a plurality of steps for bending the lead 10 in the J-shape, and the tip of the lead is bent by springing back the lead 10, at least second or later bending step out of the plurality of steps.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead bending method, and more particularly to a lead bending method for bending a lead into a J shape.

0002

2. Description of the Related Art Some surface mount type semiconductor devices have leads bent into a J shape. There are various methods for bending the leads into a J-shape for these products, but in the final step of bending the leads, a curling process is performed in which the leads are held under the lower surface of the resin mold part. This curling process involves pressing the lead against a curling die to curl the tip of the lead into a predetermined shape and holding it against the bottom surface of the resin mold. However, when the lead is pressed against the curling die, the die rubs the lead. There was a problem in that the reeds were damaged.

FIGS. 7 and 8 show an example in which the leading end of the lead is bent into a rounded shape in the first bending step in order to solve the problem of damage to the lead. this is,
If the reed is curled to a large extent during the curling process in the final process, it is likely to be damaged, so by pre-curling the lead tip in the first bending process and reducing the amount of bending during curling, the reed can be damaged. The purpose is to make it difficult to get caught. In the example shown in FIG. 7, the lead 7 is bent using the bending punch 5.
In the example shown in , a punch roller 9 is used to perform the bending process. The method using the punch roller 9 has an advantage over the method using the bending punch 5 in that the leads are less likely to be damaged.

0004

[Problems to be Solved by the Invention] As described above, the conventional lead bending method involves bending the tip of the lead into a rounded shape in the first bending, and then performing the bending process in the second bending, the third bending and the subsequent bending processes. However, in the above example, the bending angle of the lead in the first bending is about 90° at most. Since the leads are ultimately bent by about 150 degrees during curling, the above method also requires further bending of the leads in the post-process, which causes problems such as damage to the leads and peeling of the plating film applied to the leads. occurs. If the plating film peels off from the lead and adheres to the bending die, the peeled plating film will adhere to the lead during the next bending process and cause an electrical short, resulting in negative effects, so clean the bending die before processing. It is necessary to prevent the plating film from adhering to the die. Therefore, the present invention has been made to solve the above problems, and its purpose is to provide a lead that can be reliably bent without damaging the lead when bending the lead into a J shape. It is intended to provide a bending method.

[0005]

Means for Solving the Problems The present invention has the following configuration to achieve the above object. That is, in a lead bending method of bending a lead into a J shape, in the first plural steps of bending the lead into a J shape, the tip of the lead is bent into a shape close to the final curled shape, and Among the plurality of steps, at least the bending after the second bending is characterized in that the lead is bent up and the tip of the lead is bent.

[0006]

[Effect] By bending the tip of the lead to a shape close to the final curling shape during the initial bending process, the amount of bending of the lead during the curling process is reduced, and the lead is not damaged. This prevents the plating film applied to the lead from peeling off and enables highly accurate bending. By bending the lead upward after at least the second bending, the bending angle of the tip of the lead can be increased, and it becomes possible to bend the lead into a shape close to the final curled shape.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is an explanatory diagram showing the processing order from the first bending to the fourth bending in the lead bending method according to the present invention. In the lead bending process of this embodiment, in the first bending process and the second bending process, the lead 1 is
0 is flipped upward and bent, and the tip of the lead 10 is curled into an arc shape, and then third bending, fourth bending, and fifth bending (the final step of curling) are performed. In the first bending process and the second bending process, the tip of the lead 10 is bent at 9
This is to enable curling to an angle of 0° or more. In the first bending process, the tip of the lead 10 is bent to about 90 degrees, and in the second bending process, it is bent to about 135 degrees, which is approximately the same angle as the final curling angle. Then, in the third bending process and subsequent steps, the lead 10 is bent with its tip end curled. Note that the third bending step, fourth bending step, and fifth bending step are performed in the same manner as the conventional bending method. In the third bending process, the lead is bent to about 90 degrees at the base position of the lead close to the side surface of the resin molded part 12, and in the fourth bending process, the tip of the lead 10 is bent inward from the side. In the fifth bending step, the lead 10 is curled and bent so that the lead tip is held under the lower surface of the resin mold part.

FIGS. 2 to 6 show examples of lead bending in each bending process. FIG. 2 shows the first bending step. In the figure, 14 is a bending die that supports the lead from below, 16 is a knockout that supports the base of the lead from below, and 1
Reference numeral 8 denotes a knockout that flips up and bends the lead 10 between it and the bending die 14. A punch roller 20 bends the tip of the lead 10 into the shape of the bending die 14. The punch roller 20 descends from above along the side of the knockout 18 and punches the lead 10 protruding from the bending die 14.
The tip of the lead 10 is pressed against the bending die 14, and the tip of the lead 10 is bent according to the shape of the bending die 14. bending die 1
As shown in the figure, the end edge portion of the lead 10 of No. 4 that comes into contact has an arcuate cross-sectional shape, and by pressing the lead with a punch roller 20, the end of the lead 10 can be bent into a rounded shape. In this first bending process, lead 1
The tip of 0 is bent to an angle of about 90°.

FIG. 3 shows the second bending step. In this bending step, the tip of the lead bent in the first bending step is further bent into an arcuate shape. Therefore, the lead 10 is bent upward and a bending die 22 is placed at the base position of the rounded tip of the lead 10 bent in the first bending step.
are brought into contact with each other, and the base position of the arcuate portion is further bent to curl the tip of the lead 10. The end edge of the bending die 22 that comes into contact with the lead 10 has an arcuate cross-sectional shape, and the side end surface is cut off to form the lead 10.
The tip of 0 is made to escape. Note that the product was fed in a direction perpendicular to the bending direction of the lead. 23 in Figure 3
24 is a knockout, and 25 is a punch roller. The punch roller 25 is supported by a roller holder 26 and moves up and down along the outer surface of the knockout 25. The figure shows a state in which the punch roller 25 is at the lowest position. In the first bending step, the punch roller 20 is lowered to below the edge of the bending die 14, but in the second bending step, it is stopped when it comes into contact with the bending die 22. In this way, by the second bending, the tip end of the lead 10 is bent to an angle close to the final state of curling. In the embodiment, the bending process is performed to an angle of approximately 135° in the second bending process.

FIG. 4 shows the third bending step. In this third bending step, the lead 10 is bent approximately 90° downward at the base of the resin molded portion 12. In FIG. 4, the left half of the center line shows the state before bending, and the right half shows the state after bending. During bending, the resin molded part 12 is supported by being sandwiched between a knockout 30 and a bending die 33, and punch rollers 31 supported vertically on both sides of the knockout 30 are lowered to bend the lead 10. Lead 10 is attached to the bending die 33.
A recess 34 is provided to allow the curled portion of the tip of the lead to escape when the lead is bent.

FIG. 5 shows the fourth bending step. In this fourth bending step, the lead 10 is bent so as to move inward from the side. In the figure, 40 is a punch roller that rolls on the outer surface of the lead 10 to bend it, and 41 is a guide roller that presses the punch roller 40 inward. punch roller 40
Both guide rollers 41 are rotatably attached to the punch holder, and when the punch holder is lowered to bend the lead 10, the guide holder 41 moves to the bending die 4.
The punch holder is brought into contact with a stopper wall 43 provided at 2 and moved inward, thereby bending the lead 10 inward. Lead 1 is placed on the bending die 42 in the same way as in the third bending.
A recess is provided to allow the curling portion of the tip of the 0 to escape.

FIG. 6 shows the fifth bending step in which the final curling process is performed. In this step, the lead 10 is pressed against the bending die 51 by the knockout 50, thereby bending the lead 10 so as to be held under the lower surface of the resin mold part 12. The curling angle of the lead 10 after this curling step is approximately 150° in the embodiment. By the curling process, the bending angles of each lead 10 are adjusted equally, and the bending height positions of each lead 10 are aligned with a predetermined accuracy.

According to the bending method of this embodiment, by bending the lead 10 in advance to an angle close to the final curling angle, the amount of bending of the lead 10 during the curling process can be reduced, and the bending amount of the lead 10 after curling can be reduced. Dimensional accuracy can be improved. This embodiment has an advantage in that the leading end of the lead 10 can be largely curled by bending the lead 10 in the first bending process and the second bending process. In addition, the amount of bending required during the final curling process is small, and by curling using a punch roller, problems such as damage to the lead or peeling off of the plating film during the bending process can be eliminated. In the above example, curling is performed using the fixed bending die 51, but another method is also possible in which a plurality of small rollers are arranged in arcuate positions to perform curling.

In the above embodiment, the lead tips were bent in two steps, the first bending step and the second bending step.
The method for bending the lead tip is not limited to two steps. Of course, the process may be performed in two or more steps depending on the case. In addition, in the above embodiment, the first
The lead 10 was bent in the bending process, but in the first bending, only the tip of the lead 10 was bent into a rounded shape without being bent upward, and in the second and subsequent bending processes, the lead 10 was bent up and curled. You may also do so. After the second bending step, in order to deepen the curling angle, it is necessary to perform bending along with flip-up bending. In this manner, the lead bending method according to the present invention allows the lead to be bent by selecting a plurality of steps.

[0015]

[Effects of the Invention] According to the lead bending method according to the present invention,
As mentioned above, by curling the lead in the first of the multiple steps of bending the lead, it is possible to curl the lead to an angle close to the final curled shape. The bending process can be performed without damaging the lead or peeling off the plating film applied to the lead, and the lead bending process can be performed with high precision.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram illustrating a lead bending method.

FIG. 2 is an explanatory diagram showing a first bending step of a lead.

FIG. 3 is an explanatory diagram showing a second bending step of the lead.

FIG. 4 is an explanatory diagram showing a third bending step of the lead.

FIG. 5 is an explanatory diagram showing a fourth lead bending process.

FIG. 6 is an explanatory diagram showing a fifth lead bending process.

FIG. 7 is an explanatory diagram showing a first bending process of a conventional lead.

FIG. 8 is an explanatory diagram showing a first bending step of a conventional lead.

[Explanation of symbols]

10 Lead 12 Resin mold part 14, 22 Bending die 16, 23 Knockout 18, 24 Knockout 20, 25 Punch roller 26 Roller holder

Claims (1)

[Claims] Claim 1: In a lead bending method for bending a lead into a J-shape, the tip of the lead is bent into a shape close to the final curled shape in the first plurality of steps of bending the lead into a J-shape. At the same time,
A lead bending method characterized in that in at least the second bending and subsequent bending steps among the plurality of steps, the lead is bent up and bent to bend the lead tip.