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#034 Basics of Die Structure (9) Basics of Bending Die Structures

Category : Bending Work
March26, 2010

The largest shape in press formed products can be said to be bent products. The basic structure of dies for bent products will be explained below.

(1) Bottoming bending (V bending)

This is a structure of forming a shape by pushing a punch towards a material held at two pivots. See Fig. 1. This is the simplest bending structure. The bending angle changes depending on the Stroke of the punch. The bending method of this form is called "free bending". In the case of free bending the die does not have to have a V-shape as shown in Fig. 1. By preparing the punch and die to have the shape that is to be formed as shown in Fig. 1 and transferring the shape of the punch and die to the material by pressing the material between the punch and the die thereby preparing the desired shape is called "bottoming bending". Since the typical shape made using this method of forming is the shape of the letter V, generally this is called V-bending.

Fig. 1

(2) Press-down bending (L-bending)

This is the method of forming shown in Fig. 2. The bending is done after holding the material on the die using press-downs that press the material so that the material does not get shifted. The feature of this method is that the material press-down and the punch operate from the same direction. Since the material is pulled in the direction of the punch during formation, sufficient pressing area and force will be necessary.

Fig. 2

(3) Inverted press-down bending (U-bending)

This is the method of forming shown in Fig. 3. An inverted press-down is incorporated into the die, and the material is formed by pressing the material using the punch and the inverted press-down. Since both ends of the material are bent, it is not necessary to worry about the material being pulled as in L-bending.

Fig. 3

The above three methods are the basic structures of bending. Very often the bending is also done from a direction opposite to the bending directions shown in Fig. 1, Fig. 2, and Fig. 3. The bending of different bend product shapes is carried out by devising techniques so as to make the bending according to these basic forms.

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