On the effect of fixture layout on part stability and flatness during machining: A finite element analysis

Abstract

Deflection during machining can potentially introduce inaccuracies into the machined part geometry ultimately reducing its functionality. The traditional approach used in industry for fixture layout and configuration is mainly a trial and error scheme, which involves online examination of different combinations of fixture positions and clamping force magnitudes based on previous experience. Thus to be relevant, physics-based simulations of cutting processes must include the dynamics of the machine tool, fixture element, and part. In the current paper a developed simulation system is used to analyse and modify the fixture layout a priori to the metal removal process. This work analyses the effect of cutting forces, part features, and location of the fixture elements on the flatness and stability of the part. A typical industrial flexible part is used as a case study and its dynamic behaviour is analysed under different fixturing scenarios. The cutting forces are modelled using a mechanistic approach. The finite element method is used to model and analyse the dynamic behaviour of the fixtured part. Modal analysis was carried out using the finite element method and then results were verified experimentally.