Investigation of fixture design exploring pre-tensioning forces

Pre-tensioning forces are, in essence, the selective application of clamping forces applied prior to processess to create a "stress field" envelope that aids the processes of components. There are many potential functions of applying pre-tensioning forces, such as improvement of component rigidity, reduction of machining deflection, and holding of components to counteract the machining forces etc. However, the use of pre-tensioning forces has not been extensively and comprehensively investigated. The aim of this paper is to strengthen the understanding of the impact of applying pre-tensioning forces firstly on simple parts and specifically on the fixture design development by establishing a methodology of using pre-tensioning forces. To investigate the optimised fixture layout and clamping strategy, Finite Element Analyses (FEA) were established to show the effect of applying pre-tensioning forces on machining deflection. Meanwhile, the relevant model validation experiments were applied to verify the F EA models in this study appropriately. Eventually, the results show that the FEA simulations are sufficient and the use of pre-tensioning forces effectively reduces the machining deflection by using optimised clamping strategy.