DYNAMIC BEHAVIOUR OF DAMPER IN AN END-MILL

Abstract

High-speed milling is widely used in the manufacturing industry. For the efficiency of the milling process, high demands. on the material removal rate and the surface generation rate are posed. The. process parameters, determining these two rates, are restricted by the occurrence of regenerative chatter. Chatter is an undesired instability phenomenon, which causes both a reduced product quality and rapid tool wear. The cyclic fluctuation of the cutting tool that results in the engagement and disengagement of the tool from the cutting surface represents the dynamic instability in milling. This periodic oscillation of the tool is frequently called chatter. When an end-mill is used in high-speed machining, chatter vibration of the tool can cause undesirable results. This vibration increases tool wear and leaves chatter marks on the cutting surface. To reduce the chatter vibration, a layered-beam damper is inserted into the hole at the center of the tool. The purpose of this research is to design and optimize the configuration of the damper to obtain the maximum damping effect. The theoretical method which is based on the assumption of constant contact pressure and uniform deflection has been applied in order to identify the effect of the damper's configuration. Two design. variables are chosen: the inner radius of the damper and the number of slotted dampers, different material properties like Young's modulus of elasticity, mass density and speed of end mill under two different loading conditions. Using ANOVA, response surfaces have been developed for work done of end mill. Through response surfaces various interaction effect of various factors with other factors have been conducted and concluded that for all factors how the work done affects with changing of them and an important finding from the observed response that the number of fingers and inner radius of finger are the dominant factors on the work done of end mill.