A supplementary processing method of residual material in impeller plunge milling

Abstract

Plunge milling is highly suitable for processing deep groove type parts. In recent years, it has been gradually employed in the machining of integral impeller runners. However, when dealing with impeller runners that exhibit a significant blade twist, there tends to be a considerable amount of residual material left after the plunge milling process. The absence of an accurate computational model to depict these residual materials makes it challenging to plan the subsequent machining path, thereby adversely affecting processing efficiency. To address this issue, a geometric model of the material residual ridge is established. By solving the numerical equation governing the boundary characteristic curve of the residual material, a differential discretization method is employed to discretize the boundary feature curves. These curves are then connected to form a unit straight-line surface, thereby constructing an envelope model of the residual material. In order to carry out the supplementary processing of the residual material, a method is proposed based on the geometric parameters of the material residual envelope model. This method automatically divides the machining area of the residual material and plans plunge milling tool path. Simulation results demonstrate that the established residual material envelope model accurately represents the geometry of the residual material, with a volume error of less than 10 %. The supplementary processing tool path generated using the geometric parameters of the material residual material envelope model removes over 80 % of the material residual material volume. Remarkably, the supplementary processing time accounts for only 10 % of the total time required for the whole runner plunge milling process.