In this study, machining process produced continuous chip and it was observed that the chip formation took place with microcracks extension in front of the tool tip. The chip separation phenomenon is a continuous process just ahead of the tool edge and this can be assumed geometrically based on critical distance as a product of effective plastic strain and strain energy density [8]. In this study the critical distance was 4 µm and is considered small enough to produce continuous chips without distorting chips thickness. Shih and Yang,(1993)discussed estimation value for the critical distance and its effect on the accuracy and difficulties involves in obtaining a proper critical distance value. They argued that the results can only be validated experimentally in theirexperimental study on finite element predictions of residual stresses due to orthogonal metal cutting [9]. Meanwhile, Shaw [1] argues that determination of a steady state chip shape is easily done by finding the actual shape by iteration until the assumed and calculated flow fields correspond.