Factors affecting the bending process of square or rectangular profiles

Several tips can help simplify the bending of square or rectangular materials and reduce the amount of deformation of the curved portion.

Factors affecting the bending process of square or rectangular materials
Factors Affecting The Bending Process Of Square Or Rectangular Materials

Wall thickness

A curved circular, square or rectangular material involves stretching the outer diameter (OD) of the bend and compressing its ID. Thus, thicker wall thicknesses allow for tighter bend radii and more material stretchability and less distortion.

Bending method

This is a key factor in controlling distortion. Properly selected procedures help to produce consistent tolerances and precise parts. Generally, smaller materials require rotational stretch bending or compression bending, which may include a wiper mold and a mandrel. Larger materials that are bent to larger radii should use induction and incremental bending. Design deformation and material size are important factors in determining the bending method.
In many cases, there are no better factors than experience. Many well-trained bending craftsmen know the conditions required to produce acceptable products.

Material size

Larger materials that are bent to smaller radii have a greater chance of twisting than smaller materials that are bent to larger radii. Design and planning are necessary to help solve the bending problem.


After designing the part, the bending method was chosen and the procedure to bend to the appropriate tolerance was established and the machine must be set up with the appropriate tools. Depending on the design conditions, tools that can be used include bending dies, clamping blocks, follower blocks, mandrels and wiper dies. This tool may be required in whole or in part.

Internal and external lubricant

The lubricant reduces the friction between the tool and the material to be bent. As the friction is reduced, the material flows smoothly through the bending device, allowing the machine to perform its designed operation efficiently.