Modelling Clamping Force Deflection in Dexel-Based Material Removal Simulations

Abstract

Machining simulations of material removal that predict workpiece quality are a key factor in gaining an understanding of the possible causes of manufacturing defects. Particularly in the case of thin-walled workpieces, as are frequently produced in the aerospace industry, the workpiece stiffness is of utmost importance. Form deviations on the final workpiece can result due to the the process force or the clamping situation. This article presents a method for modelling the deformation due to the clamping force in dexel-based material removal simulations. To prevent distortion of the dexel model, triangulated surface meshes are generated separately for the start and end points of a dexel field by means of a Delaunay triangulation for the final contour. With the help of an FE simulation of the near contour state, the resulting displacements for the corner points of the triangles are determined and then inversely displaced. Subsequently, the new start and end points of the machined dexels are determined through a 2D interpolation. The method is validated for flatness and roundness deviations using two specimen workpieces. It shows that the prediction can be significantly improved, especially for thin-walled components.