Causes of chip deformation in automatic lathe machining

In the process of daily automatic lathe processing, there are often some workpieces that are automatically deformed. The reasons for their formation are mainly the following two

　　 The first type is formed during the cutting process, which we call the basic deformation. The chip deformation measured during free cutting with a flat rake is relatively close to the value of basic deformation. The main factors affecting the basic deformation are the tool rake angle, negative chamfering and cutting speed. The smaller the rake angle, the wider the negative chamfering and the lower the cutting speed, the greater the chip deformation and the more beneficial it is for chip breaking. Therefore, reducing the rake angle, widening the negative chamfer, and reducing the cutting speed can be used as measures to promote chip breaking.

　　 The second kind is the deformation of chips during the flow and curling process, which we call the additional deformation. Because in most cases, only the basic deformation during the cutting process cannot break the chip, and an additional deformation must be added to achieve the purpose of hardening and breaking. The easiest way to force the chips to undergo additional deformation is to grind (or press) a certain shape of the chip breaker on the rake face, and force the chips to curl and deform when they flow into the chip breaker. After the chip undergoes additional re-curling deformation, it is further hardened and embrittled. When it hits the workpiece or the flank surface, it is easily broken.