FEM ANALYSIS ON 3-DIMENSIONAL CUTTING - ANALYSIS ON LARGE-DEFORMATIONPROBLEM OF TOOL ENTRY

Tool entry process in three-dimensional cutting is simulated by finite element method. Since the chip forming process is one of large deform ation problems, geometrical nonlinearity due to the change of shape is introduced into finite element formulation. Constant strain tetrahedr a elements are used and over-constraint of incompressibility on the de formation of the finite elements in plastic region is relaxed using Na gategaal-Rice functional to make the elements as deformable as real co ntinuum. The chip formation from tool entry to steady state is realize d in the analysis. Stress and strain distributions in chip and machine d surfaces are also obtained. Low shear angle at side surface of the w ork, side flow and chip flow direction predicted are in good agreement with experimental results of cutting of plasticine.