Modeling Variation Propagation in Machining Systems With Different Configurations

Machining systems designed in different configurations have different quality performance in terms of product geometric variation. However, there exists no systematic method to predict the end-of-line product variation due to the complexity of machining processes. This paper presents a modeling methodology to analyze the variation propagation for machining systems and the impact of system configuration on quality variation. Two important sources of variations, i.e., kinematic and static variations, are included in the modeling. Kinematic deviation due to part locating and relocating is modeled using the Homogeneous Transformation Matrix. Deformation due to clamping and machining forces are modeled using the Finite Element Method, either the compliance matrix approach or the reduced stiffness matrix approach. The Monte Carlo simulation method is integrated to generate a number of workpieces with geometric dimensions and variation. Experiments are conducted to verify the model. The application is illustrated using three differently configured machining systems.