Increasing the Dimensional Accuracy of U-Bend Product of High Strength Steel Sheets by Pressure Pad

To reduce springback in U-shape of high strength steel sheet, the present paper proposes a new process parameter in U-bending technique. This paper aims to present the effect of clearance between die and pressure pad on springback behavior. The process in this work consists of four steps: (1) clamping of a sheet between a punch and a pressure pad, (2) bending with constant clamping force, (3) pushing-up at bottom of the part by using the pressure pad, and (4) final release tool. From the experimental results, decreasing of bending moment by bottom pushing-up resulted in the springback reduction. An appropriate of the clearance between die and pressure pad combined with bottom pushing-up force can be reduced springback. Our results suggested that the Y-U model, an advanced kinematic hardening, is essential for accurate numerical simulation of springback behavior.

The Effects of Polarity and Current Path in Electrically Assisted Single Point Incremental Forming of 2024-T3 Aluminum

Electrically assisted incremental sheet forming (EAIF) is a novel addition to the incremental forming (IF) method. One variation of this approach applies direct electrical current during forming. Many improvements over tradition IF can be seen by utilizing this method, to include greater part accuracy, reduced forming force, and greater formability. In order to maximize the effects of electrically assisted incremental forming, all parameters of the method must be investigated, including the polarity of the current passing through the part and the path that the applied current takes. The effects of altering these two parameters is the primary investigation in this research. It was determined that, in order to optimize springback reduction and formability during electrically assisted single point incremental forming, the tool should be assigned the positive electrode and the center of the workpiece should be assigned the negative electrode. Additionally, the mechanism behind the spalling effect inherent to EAIF is discussed.