Experimental Investigation of Workpiece/Fixture Contact and Its Implementation in Numerical Simulation of Machining Processes

Understanding the frictional contact behavior between fixture elements and the workpiece helps improve the Fixturing layout leading to better dimensional accuracy and geometric integrity of machined parts. It also affects the machining process dynamics and stability. The tangential (friction) force on the workpiece/fixture contact surface plays an important role in fixture design as it can be utilized to reduce the number of fixture components, thereby exposing more of the workpiece features to machining operations and providing a damping mechanism to dissipate input energy from machining forces out of the workpiece/fixture system. Therefore, proper modeling of the workpiece/fixture contact requires the modeling of friction conditions. The nonlinearity of the problem arises, both from the variation of the extent of contact surfaces, interrupted nature of the cutting forces and the effect of friction. The workpiece/fixture frictional contact is modeled using the finite element method. This paper presents the results of an experimental investigation of the characteristics of workpiece/fixture contact and its implementation in a numerical simulation of face milling.