JPS5937581B2 - High-density storage system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for punching lead frames used in electronic components, particularly semiconductor integrated circuits.

In lead frames for semiconductor integrated circuits (hereinafter abbreviated as IC), even if the number of leads is the same, the size of the element differs depending on the type of IC). Therefore, for reasons of assembly or characteristics, it is difficult to mount an IC element. Several types of mounting pieces must be made in different sizes, and therefore several types of punching dies are generally required.

Furthermore, the types of IC lead frames change frequently, and as a result, they often go out of use before the life of the punching die.

Conventionally, when forming a lead frame by punching, the lead frame is punched into a shape as shown in FIG. 1 through a multi-stage punching process using a continuous die.

If the shape of the element mounting piece 1 is to be changed now, it will be necessary to change the shape of the element mounting piece punch. In other words, as shown in Figure 2 (the following drawings all show lead frames divided into four equal parts from the center of the element mounting piece), the maximum dimension A of the part that will become the element mounting piece (the dimensions described below are c and d). As shown in Figure 3, use a U-shaped punch 2a to punch out the lead frame material into the lead frame material (all cases except for the center of the element mounting piece), and use a U-shaped punch 2a to adjust the element mounting piece to dimension a, and adjust the internal lead tip position. In this case, it is OK to shorten dimension a and make the element mounting piece smaller, but it is possible to make the dimension a of the element mounting piece larger than A and punch out the fourth dimension. If you want to use a' as shown in the figure, use the same U-shaped punch 2.
If B) is used, the periphery of the element mounting piece becomes uneven, and V) cannot be put to practical use.

The present invention has been made in view of these circumstances, and provides a punching method that can form lead frames of various shapes by making the punches of one or two steps of a continuous punching die compatible. do. The present invention will be explained in detail below using the drawings. FIG. 5 shows a lead frame material that has been punched in advance so that the maximum dimension that will become the element mounting piece is B and the lead spacing is C, and the B dimension is set to be larger than the conventional A dimension. This material was originally prepared to form a large element mounting piece that could not be made using a conventional U-shaped punch. However, if it is desired to maintain the dimensions a and b of the internal lead as shown in FIG. 3, it can be pulled out using a punch having the following shape. In other words, as shown in Fig. 6, the punch 2C has a comb-like protrusion with a width d on the outside of a U-shape, and the dimension d is set smaller than the lead spacing c so that d<c. Also, if the dimensions of the U-shaped part are set to a and b as in Fig. 3, then □
As shown in the figure, by forming a lead frame having a wide portion 3 at the lead end, it is possible to form a lead frame that maintains dimensions A and b as in the conventional case. This wide portion 3 is provided in advance to compensate for the misalignment between the punch that punches out the internal grooves at intervals of c and the comb-shaped punch. Of course, the a dimension of the element mounting piece can be freely selected within the range a < b, so the size of the element mounting piece can be changed while maintaining a correlation with the b dimension that determines the tip position of the internal lead. . ? To summarize the above, the dimension a of the element mounting piece can be freely selected within the range a<B with respect to the maximum dimension B of the element mounting portion formed in advance. In addition, the tip position dimension b of the internal lead corresponds to the seventh dimension a.
As shown in the figure, you can freely select. That is, according to the present invention, by providing a comb-like punch with interchangeability notes, it is possible to make the lead tip wider if the element mounting piece is to be made smaller. It is also possible to increase the size of the element mounting piece by making dimension B sufficiently large. Therefore, in order to increase the shape of the element mounting piece in the past, it was necessary to replace all the lead punches that had multiple steps, which required a great deal of expense. If the maximum dimension B of the mounting piece is set large, all that is left to do is to replace the comb-like punches of any shape in the process of punching out the element mounting piece, and the element mounting piece of any shape can be formed. Since it is possible to form a lead frame that has the same structure, it is possible to reduce costs and improve work efficiency.

[Brief explanation of the drawing]

Figure 1 is a plan view of the lead frame, Figures 2, 3, and 4.
The figure is an explanatory diagram of the conventional method, and FIGS. 5 to 7 are explanatory diagrams of the present invention. DESCRIPTION OF SYMBOLS 1... Element mounting piece, 2a, 2b, 2c... Punch punch, 3... Wide part, A, B... Maximum dimension of element mounting part, A, at... Element mounting Single dimension, b... Internal lead tip position dimension, c... Lead spacing, d... Comb tooth width.

Claims (1)

[Claims] 1. In a method for punching lead frames for electronic components using a continuous die, among the multiple steps of the continuous die, a lead frame material in which an element mounting part and an internal lead are integrally formed is A method for punching lead frames for electronic components, characterized by using a comb-shaped punch in the process of separating and molding the leads.