Paper Title
Dynamic modeling and parametric analysis on Nonlinear vertical cutting process with Variable stiffness

Abstract
In this investigation a nonlinear dynamic analysis was conducted on metal cutting process to evaluate system stability regarding to changing in the metal stiffness. For this propose a model with the forces due to coulomb friction and variable stiffness was solved. The manner is based on multiple time scales perturbation method that presents acceptable solution for non-resonance condition and stiffness with time variable. The important role of feed, depth and length of cutting and also effect of physical constants in system stability was carried out. Keywords- Metal cutting Process, Perturbation Methods, Multiple Time Scales, Time Variable Stiffness