Roller design and optimization based on RSM with categoric factors in power spinning of Ni-based superalloy

Power spinning is a single-point high-pressure forming process which is usually studied with ideal regular blank. However, in some cases, the blank adopted in this process is from conventional spinning process with non-uniform wall thickness and springback. Therefore, the forming accuracy cannot be guaranteed because of the irregular blank. In this paper, cone, step, and arc rollers are compared and the length change of deformation zone is calculated to further understand the forming mechanism of different roller shapes. Multi-step process simulation considering conventional spinning and power spinning is established. The influence of roller parameters such as roller nose radius, straightening zone in step roller, and bite angle on the maximum roller force in feeding direction is discussed. In addition, the continuous factors such as installation angle and discrete factor roller shape are studied based on the response surface method (RSM) with categoric factors. The results show that roller shape has a big influence on the workpiece forming quality in power spinning process. Step roller is more suitable for use in this work. The roller nose radius and installation angle have great impacts on the maximum roller force in feeding direction.