A Solution to Die Marks in the Bending Operation of an Aluminum Alloy Shaft

This study presents a method for solving the scratch problem on the workpiece surface of an aluminum alloy shaft graded 6063 after V -die bending operation. This method presents the prevention of metal-to-metal contact between the workpiece and die surfaces. The method consists of: (1) bending using 1-mm-thick high-density polyethylene between the steel die and the aluminum alloy workpiece for preventing the touching surface; (2) bending using a polytetrafluoroethylene polymer for die making; (3) bending using a polyoxymethylene polymer for die making. The results show that the first method did not protect the workpiece surface from die marks after bending while the second and third methods did. However, using an elastic material to make the die causes a large elastic deformation and also affects the shape quality of the bent workpiece. This problem can be improved by choosing a type of polymer that has low elastic properties and designing a structure of the die to help to improve its stiffness.