Chatter suppression in the milling process of the weakly-rigid workpiece through a moving fixture

This article presents a new method to suppress the chatter vibrations in the milling process of the weakly-rigid workpiece through a moving device. The basic idea is to design a moving fixture to instantaneously and continuously provide additional stiffness and damping to the instantaneous contact position between the moving fixture and the workpiece, and as the device moves, the chatter vibrations of the workpiece during the whole process are suppressed without the need of any other additional hardware. Two theoretical means, i.e. the structure split-assembly technology and the fractal contact theory, are combined to mathematically model the underlying dynamic behavior of the workpiece under the support provided by the moving fixture. The workpiece is divided into three parts, i.e. the machined part, the machining part and the part to be machined. The dynamic response of each part is separately analyzed and then theoretically assembled to calculate the whole workpiece's varying dynamic characteristics, which involve the support influence induced by the moving fixture. The effect of material removal on the workpiece's dynamic characteristics is also integrated into the analyzing procedure. Based on the above analysis, the dynamic governing equation of the thin-wall milling process with the moving fixture is finally established and solved to predict the stability lobe diagrams (SLDs). The validity and reliability of the proposed method are verified by conducting a series of actual milling tests with and without the support of the designed moving fixture.