How important is it to use the proper bend radii when designing torsion springs and wire-forms? This is a topic that, when overlooked, can often result in excessive cost caused by breakage and therefore should be addressed prior to final design.

Breakage (fracture) will sometimes occur at the bends on torsion springs or wire forms when the radius is too tight (small). Higher concentrations of stress occur in these areas caused by the loads being applied to the sharp bends in the material.

Stress concentrations factors can be estimated. It is best, however, to design the radius to be 1.5 times the diameter of the material.

-The 18th China(Guangzhou)Int’l Springs Industry Exhibition