Effect of workpiece/fixture dynamics on the machining process output

Abstract

Selection of fixturing system parameters is a very important part of any manufacturing process. These parameters become more important when machining flexible parts, as the classical trial-and-error approach used in industry leads to more scrapped parts before reaching an acceptable fixture scenario. The presented simulation system integrates the effects of workpiece/fixture dynamics with the other factors contributing to the machining process dynamics and stability. It provides more accurate prediction of the process output, which helps in the design of the optimum fixture configuration prior to the production stage, consequently reducing both cost and lead time. Modelling of the frictional contact behaviour between the fixture element helps improve the prediction accuracy of the simulation system which accelerates the convergence to the optimum fixture configuration design and consequently improves the machined part dimensional accuracy and geometric integrity. The developed simulation is capable of modelling complicated part geometries by interfacing with commercial packages. The workpiece/fixture frictional contact is modelled using the finite element method. The frictional characteristics of the contact were determined experimentally. Face milling was used as a case study. Simulation results showed good agreement with the experimental validation.