An approach for optimising the fixturing configuration in flexible machining fixtures

Abstract

Optimal fixture configuration is critical to minimise the machining distortion of the workpiece. This study presented an approach for optimisation of fixturing configuration in flexible machining fixtures. Herein, a flexible fixture system composed of adaptive clamping unit, locating unit, and auxiliary locating unit was investigated. Response surface methodology (RSM) was employed to describe the relationship between fixturing parameters (distance between two zero-point fixtures m 1, the clamping force of float fixture m 2, and quantity of float fixture m 3) and machining distortion. Furthermore, sensitivity analysis was implemented to evaluate the effects of fixturing parameters on machining distortion. Adaptive penalty function (APF) was constructed to search optimal settings of fixturing parameters. Comparative analysis of different optimal fixturing parameters obtained by RSM and APF was conducted. Single-sided component was adopted to validate the effectiveness of the proposed approach. Machining distortion was found to first decrease and then increase with the augment of m 1 and it reduced with the increment of m 2 and m 3. Besides, m 3 exhibited the greatest influence on machining distortion, 61.78%. The interaction between m 2 and m 3 resulted in the lowest influence, 0.019003%. Furthermore, the maximum machining distortion through optimised flexible clamping was only 0.312 mm, which reduced by 57.6% compared to traditional clamping.