Life expectancy estimation of the micro tool cutting edge using fem simulation of the cutting process

Abstract

The paper considers the issues related to the failure causes of microtool cutting edge using finite element process simulation of micro-cutting, and investigation into various factors influence on cutting edge tool life expectancy. There has been a lack of studies devoted to microstructure failure causes recently. It is due to difficulty in microdrill breakdown cause identification by practical experiments. Because cutting processes occur at small sizes so that it is hard to measure cutting forces, the temperature in the cutting zone, or monitor tool wear level, a slight change in these parameters would lead to sudden tool failure. Therefore, a method for micro-cutting process simulation, which has got boosted recently, is proposed.

A simulation model of the cutting process with a round blade made of plastic material with subsequent establishing wear rate of the microtool cutting blade depending on the ratio of cut thickness to round edge radius (a/ρ) by predicting the contact temperature in the cutting zone by means of known analytical relationship for wear rate of the tool under cutting is developed. Orthogonal cutting in the 2-D model is considered. Geometrical dimensions are selected in proportion to cut thickness. The tool is also deformable. Forces and boundary conditions are set in displacements.

On the basis of a finite element method developed to the simulation micro-cutting process modeling, it is found that changes in the studied values are extreme, and accordingly some recommended values of the a/ρ ratio have been found, which provide the longest life expectancy for microtools. The obtained results show that decrease in a/ρ ratio induces more intensive wear occurs due to unfavorable conditions of chip formation, which is in good agreement with the known experimental data.