Abolfazl lotfi-aski - Department of Agricultural machinery Mechanical Engineering, Science and Research branch, Islamic Azad University, Tehran, Iran.
Behzad Mohammadi-Alasti - Department of Agricultural Machinery Mechanical Engineering, Islamic Azad University, Bonab Branch, Bonab, Iran
Mohammad Homaei; - Department of Agricultural Machinery Mechanical Engineering, Islamic Azad University, Bonab Branch, Bonab, Iran
Ghader Rezazadeh - Department of Agricultural Machinery Mechanical Engineering, Islamic Azad University, Bonab Branch, Bonab, Iran

Machine tools is a machine for shaping or machining metal or other rigid materials, usually by cutting, boring, grinding, shearing or other forms of deformation. Vibration is an undesired phenomenon in machine tools and can Increase their performance negatively. In this work reduction of undesired vibrations in machine tools has been investigated. The machine tools has been simulated as a five-degree-of-freedom discrete system. Subsequently, in order to reduce the undesired vibrations of the system a dynamic vibration absorber with two unknown parameters has been added to the system in different positions, consequently, one degree has been added to the degree-of-freedom of the system and has been reached to six. Then the governing equations have been obtained by utilizing Newton‟s second law and the equations have been solved. For each position optimum values of unknown parameters (mass absorber , stiffness absorber have been acquired through trial and error to obtain minimum vibration amplitude in the components of machine tools. The results have shown that the head of the machine tool was the best palace to add the vibration absorber also this absorber has least cost between obtained optimum absorbers. The two parameters were obtained for optimal Absorber 5 kg and respectively

machine tools, optimum absorber, reduce vibration