Investigations on a novel quadratic spiral tool path and its effect on incremental sheet forming process

Abstract

Incremental sheet forming (ISF) is considered as a flexible sheet metal forming process suitable for rapidly producing complex sheet metal parts, and the tool path has a vital impact on the forming quality. The balance between efficiency and geometric accuracy is still challenging in tool path generation algorithm for the ISF process. In the present work, a novel quadratic spiral tool path (QSTP) generation algorithm has been developed for the ISF process. For better understanding the impact of QSTP, the thickness thinning, forming cycle time, geometric accuracy, and surface quality are case-studied by using two typical parts with varied wall angle and compared with conventional spiral tool path (CSTP). Two different materials AA5052 and DC05 are used to evaluate the influences of sheet material properties. In addition, an analytical model is proposed to evaluate the surface quality of the part made by QSTP, which is also validated by experiments. Experimental results confirm that QSTP can improve surface quality and geometric accuracy, reduce horizontal forming force, and relieve severe thickness thinning compared with CSTP. Results also demonstrate that QSTP generates smoother and shorter tool path compared with CSTP, which ensures the reduction of forming cycle time. Experimental comparison in forming AA5052 and DC05 by QSTP shows that larger ratio of yield stress to Young’s module of the sheet metal may cause larger geometric deviation, but the material properties do not affect the thickness thinning mode which still generally follows the Cosine law in QSTP.