Fluctuation analysis of process flow based on error propagation network

It is a key issue to reduce process fluctuation for improving machining quality of workpiece. For multistage machining processes, it is difficult to identify the fluctuation sources of process flow due to the complicated interactive effects among different stages. In view of this issue, a fluctuation evaluation and identification method is proposed based on machining error propagation network. A fluctuation propagation equation of process flow is established, and a machining error propagation network is constructed, which consists of machining form feature and machining element nodes. Based on this, fluctuation propagation coefficient is defined, and node state variation risk (NSVR) of different node is measured, and the priority of node can be identified according to its NSVR. A three stage process of a box part is used to verify the proposed method.