Relationship between bending radius of bending machine and tube diameter

General rules for bending radius

Minimum bending radius: In general, the minimum bending radius of a tube should not be less than two times (2D) the outside diameter of the tube, e.g., for a tube with an outside diameter of 20mm, the minimum bending radius is usually 40mm.

Standard bending radius: For most applications, the standard bending radius is two to three times (2D-3D) the outside diameter of the tube. For example, for a tube with an OD of 38mm, the standard bend radius is 76mm-114mm.

Special applications: In some special applications, such as aerospace or engine conduits, a smaller bend radius may be required, but a more complex process and tooling design is needed.

Main influencing factors

Material properties: Tubes made of different materials (e.g. stainless steel, carbon steel, aluminum tubing, etc.) have different bending properties, so the yield strength and modulus of elasticity of the material need to be taken into account when selecting the bend radius.

Wall thickness: the wall thickness of the tube will also affect the choice of bending radius. Tubes with thinner wall thicknesses are more likely to deform or rupture at smaller bending radii.

Mold design: the appropriate mold design is essential to ensure the quality of pipe bending. The radius of the mold should be based on the outer diameter of the tube and the required bending radius for accurate design.