Chip type
Different workpiece materials and different cutting conditions have different degrees of deformation during the cutting process, resulting in different chips. Depending on the degree of deformation during the cutting process, chips can be classified into four different types
1) Banded chips
The bottom layer of the banded chips is smooth, and the upper surface is hairy with no obvious cracks. When cutting plastic metal materials such as mild steel, copper, aluminum, and malleable cast iron, it is easy to get this chip when the cutting depth is small, the cutting speed is high, and the cutter has a relatively large rake angle. When ribbon chips are formed, the cutting process is smoother, the cutting force fluctuates less, and the surface roughness value of the machined surface is smaller.
2) Nodal chips: Nodal chips are also known as squeezed chips. The underside of such chips sometimes cracks, and the upper surface is noticeably jagged. Nodal chips mostly appear on metal materials with low plasticity (such as brass), and knotted chips often occur when the cutting speed is low, the cutting depth is large, and the tool rake angle is small. This chip is also easy to get when the process system is not rigid enough and carbon steel materials are processed. When extrusion chips are generated, the cutting process is not very stable, the cutting force fluctuates greatly, and the surface roughness value of the machined surface is large.
3) Granular chips
Light class
Granular chips are also known as unit chips. This chip occurs when plastic metals are cut with very low cutting speeds and large cutting depths with small or negative rake angles. When the unit chips are generated, the cutting process is not stable, the cutting force fluctuates greatly, and the surface roughness value of the machined surface is large.
4) Crushing chips
When cutting brittle metals (cast iron, bronze, etc.), due to the low plasticity and tensile strength of the material, the local metal close to the cutting edge and rake face in the cutting layer is squeezed without obvious plastic deformation, forming irregular fragmented chips. The harder the workpiece material, the smaller the rake angle of the tool, and the greater the depth of cut, the more likely it is to chip chipping. When chipping chips are generated, the cutting force fluctuates greatly, and the uneven cutting edge of the machined surface is easy to damage. Cutting forces and cutting heat are concentrated at the cutting edge.
