Variation Propagation Analysis and Modelling in Multistage Machining Processes

Variation propagation analysis and modelling in multistage machining processes (MMPs) is of great significance for estimating the size and geometrical quality of processed parts, monitoring the machining processes, diagnosing the deviation sources, and realizing the evaluation and selection of process planning. In this paper, after analyzing the error sources and their propagation modes in the part machining process, the differential motion vectors are used to represent locating datum-, fixture-, and machining-induced variations. Then a series of coordinate transformations of variation sources are employed to set up the mathematical relationship between the key product characteristics and various machining process parameters, and a linear explicit Stream of Variation model (SoV) of multistage machining processes is established. Finally, an example is given to validate the proposed model.