Stream Of Variation Modeling And Monitoring For Medium And Small Batch Multistage Machining Process Of Rotary Parts

Stream of variation, formed by the propagation, transmission andaccumulation of variation sources, such as fixture error, datum error and toolerror, is one of the major factors contributing to the quality of thecharacteristics of rotary parts in multistage machining processes. Modelingand monitoring of stream of variation in multistage machining processes ofrotary parts provides theoretical support for dimensional variation reductionas well as rotary parts machining process improvement.Differential motion vector, a concept in robotics, is adopted to analyzethe fixture and positioning errors transmission in turning processes. A methodof stream of variation for rotary parts, which reveals the rule of variationcoupling and transmission among stations is built based on state space model.A parmeter estimation model for multistage rotary parts machiningprocess is also proposed based on the variation model. By integrating thevariation model and historical data, this model is capable of dealing with theproblem of parameters estimation for multistage rotary parts machiningprocesses under medium and small batch production condition. Based on theestimated parameters, a monitoring scheme for multistage rotary partsmachining processes is also proposed and verified by several cases of the machining processes of astronautical valve shells produced in a domesticaerospace corporation.