Modelling of machining error flow based on form features for multistage processes

Abstract

The machining quality of a workpiece is determined by many machining process elements, such as the machine tool, fixturing, and process planning, etc. It is especially observed that there is a propagation chain of quality attributes in the multistage machining processes (MMPs). Owing to the propagation chain of quality attributes, the machining quality of the workpiece at a single stage is determined not only by the machining elements of the current stage, but also by the quality attributes of its previous stages. In order to describe the propagation chain, a form-feature-based quality control model for MMPs is proposed. Based on this, a linear error propagation model is established by the use of a rigid-body kinematics method, which can explicitly describe the mapping relationship between machining errors of quality attributes and machining process elements. In order to have some comparison with the error propagation model, the above linear regression model has been built to enable correlated quality attributes to be determined with this error propagation model. A workpiece has been used to show that the error propagation model can effectively describe the propagation chain of the quality attributes.