INVESTIGATION OF HIGH-SPEED CRYOGENIC MACHINING BASED ON FINITE ELEMENT APPROACH

Abstract

THE SIMULATION OF CRYOGENIC MACHINING PROCESS HAS BEEN ALWAYS LIMITED AND HAS LESS BEEN STUDIED DUE TO THE NEED TO USE A THREE-DIMENSIONAL MODEL IN THE FINITE ELEMENT METHOD AND AS WELL AS THE HIGH PROCESS DURATION TIME. TO RESOLVE THIS LIMITATION IN THIS STUDY, A 2.5D FINITE ELEMENT MODEL USING THE COMMERCIAL FINITE ELEMENT SOFTWARE ABAQUS HAS BEEN DEVELOPED FOR THE CRYOGENIC MACHINING PROCESS AND BY CONSIDERING MORE REALISTIC ASSUMPTIONS, THE CHIP FORMATION PROCEDURE INVESTIGATED. IN THIS METHOD THE LIQUID NITRO-GEN HAS BEEN USED AS A COOLANT. AT THE MODELING OF FRICTION DURING THE INTERACTION OF TOOLS – CHIP, THE COULOMB LAW HAS BEEN USED. IN ORDER TO SIMULATE THE BEHAVIOR OF PLASTICITY AND FAILURE CRITERION, JOHNSON-COOK MODEL WAS USED AND UNLIKE PREVIOUS INVESTIGATIONS, THERMAL AND MECHANICAL PROPERTIES OF MATERIALS AS A FUNCTION OF TEMPERATURE WERE APPLIED INTO THE SOFTWARE. AFTER EXAMINING ACCU-RACY OF THE MODEL WITH PRESENT EXPERIMENTAL DATA, THE EFFECT OF PARAMETERS SUCH AS RAKE ANGLE AND THE CUTTING SPEED AS WELL AS DRY MACHINING OF ALUMINUM ALLOY BY THE USE OF COUPLED DYNAMIC TEM-PERATURE SOLUTION HAS BEEN STUDIED. RESULTS INDICATED THAT AT THE CUTTING VELOCITY OF 10 M/S, CRYOGENIC COOLING HAS CAUSED INTO DE-CREASING 60 PERCENT OF TOOLS TEMPERATURE IN COMPARISON WITH THE DRY COOLING. FURTHERMORE, CHIP WHICH HAS BEEN MADE BY CRYOGENIC MACHINING ARE CONNECTED AND WITHOUT FRACTURE IN CONTRAST TO DRY MACHINING.