An Improved Equivalent Fixture Error Model for Machining Process

Although the equivalent fixture error approach used in variation propagation can directly model the process physics regarding how datum-induced, fixture-induced and machine tool-induced errors generate the same error pattern on part features, the developed equivalent fixture error compensation technique did not consider machining-induced variations. Machining-induced variations are often caused by geometric-thermal effects, cutting force-induced variations, and/or cutting-tool wear, etc. Such machining-induced variations are an important factor that influences the part quality. Without considering machining-induced variations, the application of EFE model for error compensation will be limited. In order to overcome this limitation, this paper extends current equivalent fixture error to include machining-induced variations. This paper shows the benefits of the extended model through a case study.