Simulation of accompanying phenomena in the cutting zone during drilling of stainless steels

摘要

The paper described the cutting process analysis with CAD systems by drilling. The start of process is defined from cutting process (with one the cutting edge). Simulation of machining (cutting and drilling). Finite Element Method (FEM) based techniques are used to simulate high speed machining processes and offer several advantages including prediction of tool forces, distribution of stresses, and temperatures, estimation of tool wear, optimization of cutting tool geometry, and cutting conditions. However, workpiece material flow stress and friction characteristics at cutting regimes are not always available for most materials. The flow stress or instantaneous yield strength at which workpiece material starts to plastically deform or flow is mostly influenced by temperature, strain and strain rate factors. Accurate and reliable flow stress models are considered highly necessary to represent workpiece material constitutive behavior under high-speed cutting conditions. The problems creating is the parameters the next technological operations the main drilling. This article presents the results of experiments that concerned the verification of machined surface conditions of workpieces from a new austenitic stainless steel with Extra Low Carbon (ELC) Cr202Ni10MoTi and cutting tool wear. The results of cutting zone evaluation under cutting conditions - cutting speed vc= 80 m/min, depth of cut aP= 2,75 mm and feed f= 0.08 mm per rev., are a definition of shear level angle ФI. For Cr20Ni10MoTi steel ФI is 35 to 38°. The acquired results are interesting in that for the defined conditions we can achieve a quality outer surface after cutting with roughness parameters down to around 0.8 µm. Very good results were mainly achieved when cutting speed was 80 m/min and the feed was 0.08 mm per rev. for steel Cr20Ni10MoTi. The value of Rz (following ISO 4287, it is the upper limit of unevenness in outer sur--faces) did not exceed a value of 2.8 µm.