Effectiveness of particle and mass impact damping on tool vibration during hard turning process

In the machine tools, tool vibration is an undesirable phenomenon which affects tool life, quality of machined surface and produces irritating noise. This tool vibration is due to the interaction between metal cutting process and forces acting on the machine tool. In this investigation, an attempt was made to reduce tool vibration during turning of hardened steel using particle and mass impact dampers. A mass impact damper used in this investigation consists of a concentrated mass made of copper mounted on the bottom of the tool holder and particle damper consists of copper particles of 3.5 mm diameter positioned along the axis of the tool holder. Particle size and its location were designed using computational analysis and impact hammer–based modal testing was performed for both dampers. When these dampers were mounted on the tool holder, particles will collide with each other and subdue the vibration produced in the tool holder. Cutting experiments were conducted to study the influence of mass and particle damping on tool vibration and cutting performance during turning of hardened AISI4340 steel using hard metal insert with sculptured rake face. From the results, it was observed that the use of mass impact and particle dampers enhances the rigidity of the tool holder which, in turn, reduces tool vibration and improves the cutting performance. Among the two dampers, it was found that the presence of mass impact damping provides superior cutting performance when compared to particle damping.