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#026 Basics of Die Structure (1) Structure of Blanking Dies - 1

Category : Shearing work
January29, 2010

A blanking process is that of forming contour shapes as is shown in Fig. 1. The contour shape may become a product by itself, or some times may become a blank for bending or drawing operations. Normally, in the blanking process, the product passes through the die and falls down. A die of this type of structure is called a blanking die.

[Fig. 1] Formed shape

In a blanking die, the punch and the die are prepared to match with the shape of the product. The punch is made smaller than the die by the amount of the blanking clearance. When the material is processed, blanking chaff gets adhered to the punch. The stripper is the part used for the purpose of removing this blanking chaff from the punch. Since it is sufficient for the stripper to merely remove the blanking chaff from the punch, there is no problem even if the stripper is fixed on the side of the die plate. A stripper of this form is called a "fixed stripper".

Since this is a blanking die using a fixed stripper, it is called a blanking die of the fixed stripper structure. Since the material passes in between the fixed stripper and the die plate, a suitable gap is provided between them. Although there is no rule about this, but a guideline for the size of this gap is about 5 to 10 times the material plate thickness. Further, in this gap part, the material is guided along the width direction of the material.

Although a form is shown in Fig. 2 in which the punch is studded in the punch plate, if the cross section of the punch is large, the punch may also be affixed directly to the punch holder. On the other hand, if the punch is small and a thick material is being blanked, a punch packing plate may be placed between the punch plate and the punch holder. There can be may variations even in the basic structure.

[Fig. 2] Die structure

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