Optimal Design of the Shape of a Non-Ball Mandrel for Thin-Walled Tube Small Radius Cold Bending

In the field of cold bending, it is necessary to use ball mandrels, especially bend thin-walled tubes with a small radius. However, bending process mandrel complex and expensive, easy jam core inside tube. To solve these issues, we designed two kinds hollow non-ball schemes low stiffness that were suitable for radius tubes. We evaluated forming quality numerically influence section length thickness on indices. Our results showed has greater than length. As section’s increased, wrinkling rate first declined by approximately 40% then increased above 50%. When was 11 mm in scheme 1 13 2, reached minimum values 1.32% 1.50%, respectively. flattening decreased more 60% thinning about 40%. A multi-objective optimization indices carried out ideal point method grey wolf optimizer. By comparing before after optimization, feasibility using proposed proved, standard cylinder therefore recommended.