SUPPRESSION OF CHATTER VIBRATION OF BORING TOOLS USING DAMPERS

摘要

Chatter is a problem of instability in the metal cutting process. During turning, the material deformation process induces a broad-band excitation of the machine tool, and, as a result, relative dynamic motion between the boring bar and the workpiece frequently occurs, commonly referred to as chatter [1]. This phenomenon is characterized by violent vibration, poor quality of surface finish and causes a reduction of the life of the tool. In all cutting operations like turning, boring vibrations are induced due to the deformation of the workpiece. In boring operations, the boring bar is subjected to forces from both the cutting speed and the cutting depth direction [2]. A boring bar can usually be characterized as a slender beam and is generally the weakest link in a machine tool system [1].This implies economical disadvantages during machining. The main objective of the proposed work is to design damped tool holder for exiting machine tool with low cost. In this investigation, improvement of the damping capability of boring tool and suppression of chatter vibration using dampers are analyzed. The inertia mass of the dampers have been increased to suppress the chatter vibration. The materials selected for the dampers are nitinol, tungsten carbide and tungsten-nickel-copper alloy. Finite elements analysis has been performed to study the dynamic behavior of tool holder using the selected different damping materials. The main contributions of the current study are observed that the natural frequency of the boring tool has been enhanced with dampers. From harmonic and transient analysis, it is observed that there is reduction in amplitude of vibration with respect to the frequency and time taken to decay the amplitude of boring tool with dampers. Hence the result of finite element analysis of tungsten-nickel-copper alloy damper shows that there is a significant improvement in dynamic behavior when compared with other damping materials.