Focus and core metal cutting process is the formation process of research chip. Hard cutting process generally produces serrated chip. Dr. kfkoch and Dr. p.fallbochmer think, chip form hard cutting chip thickness affected the most, when the chip thickness is less than 20μm easy to produce ribbon cuttings, otherwise generate serrated chip. The main reason for the formation of serrated chip is the tool rake face of the workpiece material being squeezed and piled near the rake face, continue to move the cutting tool causing sudden break-chipping materials.

Sawtooth chip formation mechanism has many famous assertion. 1964 recht proposed mutation when cutting shear instability of the classical model, when the nominal stress-true strain curve slope is zero, that the negative effects of localized temperature change rate is equal to or greater than the strength of the strength of the resulting strain hardening When a positive impact within the material plastic deformation zone will mutate cut. Houzhen-bin Oklahoma State University and rangakoⅱ1and proposed serrated chips formed during the thermodynamic model, their experiments showed that cutting speed and feed rate plays an important role in the occurrence of buckling in shear.