An Introduction To Precision Sheet Metal Bending Process

By Author: Stuart Small
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To produce different materials made of precision sheet metal, it is needed to give it different shapes. For giving different shapes to a precision sheet metal it has to be bent. Without bending it is impossible to produce any materials.

What is bending?

Bending is a manufacturing process by which a sheet metal can be deformed to change its shape. The metal is stressed above its own yield strength but just below its highest tensile strength. In bending, refers to the deformation about one axis only, there is little change to the material surface area.

Different shapes can be produced in bending by using standard die sets or bend brakes. By using die sets materials are given v-shape and by using press brakes a number of shapes can be given to the materials.

Principal Types of Bending

Various types of bending can be done, such as—

Air Bending
Bottoming
Coining
V Bending
U Die Bending
Wiping Die Bending
Double Die Bending
Rotary Bending

Air Bending

One of the principal metal forming processes. It is simple ...
... but it has a large field of application. It is done with the punch. While the punch touches the work piece, it bends. As the punch is released it springs back. The material, grain, temper and thickness establish the amount of spring back ranges from 5 - 10 degree.

For obtaining different bending angels there is no need to change any equipment or dies because the bend angels are determined by the punch stroke.

Bottoming

In bottoming, the work piece and the punch bottom on the die. In this process a controlled angel can be get with very little spring back. In this type of bending more tonnage is required than air bending. Required inner radius of the work piece is minimum 1 material thickness.

The final position of the punch, the clearance between the punch and die surface is less than the blank thickness, helps to reduce the spring back. In comparison with the air bending bottoming requires more force.

Coining

In coning a work piece is subjected to extremely high pressures to encourage plastic flow on the surface of the material. It is a cold working process. In this process compressive stress is applied to the bending region to increase the amount of plastic deformation. The amount of spring back is reduced by it. It is used to get high relief or very fine features.

V Bending

V bending is used widely and in this process the clearance between the punch and die is constant. This bending operation is performed by compressing the sheet metal between a matching V-shaped punch and die.

U Die Bending

In this process a backing pad is used to force the contacting with the punch bottom and this process is performed when two parallel bending axis are produced in the same operation.

Wiping Die Bending

In this process the sheet metal is bent on one edge to 900. By the stroke position of the punch the flange length can be easily changed and the bend angel can be easily controlled. It is also known as flanging.

Double Die Bending

When two acting operations are done on the work piece one after another then it is called double die bending. It can reduce spring back by enhancing strain hardening.

Rotary Bending

In this process a rocker is used instead of a punch. It requires less strength and force. In this process there is no need of blank holder and in it more than 900 bending angel is available.

Author About:

Stuart Small from Stevens Rowsell Sheet Metal Engineering writes about Precision Sheet Metal Bending Process. For more information about Precision Sheet Metal Bending Process visit www.stevensrowsell.com