Types of Chips in Metal Cutting – How Do Chips Affect the Cutting Process

1. Continuous chips

Continuous chips also referred to as ribbon-type chips, when machining plastic metal materials, such chips are usually obtained when the cutting thickness is small, the cutting speed is high, and the tool rake angle is large. Its cutting process is balanced, the cutting force fluctuation is small, and the machined surface roughness is small. Its inner surface is smooth and its outer surface is hairy.

2. Non-homogeneous chips

This kind of chip is different from the ribbon chip in that the outer surface is serrated, and the inner surface sometimes has cracks. This kind of chip is mostly produced when the cutting speed is low, the cutting thickness is large, and the tool rake angle is small.

3. Continuous chips with built-up edges

When cutting ductile materials at high temperatures and high speeds, high friction will be produced between the tool and the part, then the chips easily stick to the edges of the cutter, and add up in successive layers, which form the built-up edges.

4. Discontinuous chips

This is a chip of brittle material. The shape of the chip is irregular and the machined surface is uneven. From the cutting process, the chip deformation before fracture is very small, and the chip formation mechanism is different from that of plastic materials. Its brittle fracture is mainly due to the stress of the material exceeding its tensile limit. Machining brittle hard materials, such as high silicon cast iron, white iron, etc., especially when the cutting thickness is large, this chip is often obtained. Because its cutting process is very unstable, it is easy to damage the tool, it also damages the machine tool, and the machined surface is rough, so it should be avoided as much as possible in production. The method is to reduce the cutting thickness and make the chip into a needle or sheet shape. At the same time, the cutting speed should be properly increased to increase the plasticity of the workpiece material.