Chip deformation may consist of two parts: the first part is formed by the cutting process, which we call the basic deformation. Metal cutting process, the chip is easily broken, and wire-tapping is directly linked to the deformation of the chip, so the chip breaking research from research chip deformation essential principle of law to start. In Japan too hard tap cutting chips high strength, high ductility, high toughness materials, the idea of ??increasing the chip should be deformed to reduce its ductility and toughness, easy to achieve the purpose of the breaker. - Over the years, scholars at home and abroad to shape and form the chips were a lot of in-depth research, build dozen chip formation model, has achieved important results in terms of activities in the direction of the chip, the chip curler mechanism and chip breaking methods. The main factors that affect the basic deformation are the tap before the horn, negative chamfer, cutting three. The chip is subjected to plastic deformation larger brittle more obvious, the more easily broken.