Simulation of Workpiece Vibrations in Spindle Direction during Milling

The occurrence of chatter vibrations in milling processes often results in bad surface qualities and in an increased tool wear. When using special fixture systems for structural parts in the aerospace industry, the vibrations of the workpiece and the fixture can become critical due to their limited stiffness. For the process design, a prediction of the appearance of these kind of vibrations using specialised simulation approaches is very helpful. In this article, a simulation system is presented, which is able to simulate chatter vibrations of the workpiece in spindle direction, taking the dynamic behaviour of the thin-walled bottom of the workpiece and the fixture into account. Experiments were conducted to demonstrate the basic effect and to validate the simulation system. Furthermore, the machining and the simulation of a pocket of a structural component for aerospace applications is analysed.