In the cutting process, due to the workpiece material, the geometric Angle of the tool, the cutting amount and so on different, the chip deformation degree is different, so the chip type is different. There are four main types of common chips.
(1) Strip chip (Fig. 1-a)
The chip is long and ribbon-like, and the bottom layer of contact with the tool front surface is smooth and without cracks, and the outer surface is furry.
When processing plastic metal, if the cutting thickness is small, the cutting speed is high, the tool raceway is large, generally obtains this kind of chip.
Its cutting process is relatively stable, cutting force fluctuation is not large, the workpiece has been processed surface roughness is low, but the processing should pay attention to chip breaking.
(2) Crushing chip (Fig. 1-b)
Chip shape is still continuous shape, the degree of deformation than the strip chip, chip bottom has local cracks, the appearance is serrated.
It is generally in the cutting speed is low, the tool rake Angle is small, the cutting thickness is larger, the processing of medium hardness plastic metal.
When the extrusion chip is formed, the cutting force fluctuates and the surface roughness of the workpiece is higher.
(3) Unit chip (Fig. 1-c)
If the shear stress on the shear surface of the crammed chip exceeds the strength limit of the metal, the crack will run through the thickness of the chip, forming a trapezoidal element chip.
This chip mostly occurs in the tool rate-angle is small, low cutting speed, processing poor plasticity of the material.
In the process of machining, its cutting force fluctuates more and the surface quality of the workpiece is worse.
(4) Crushing chip (Fig. 1-d)
When cutting brittle metals, due to the poor plasticity and low tensile strength of the material, the cutting layer material often produces brittle fracture without plastic deformation, and forms irregular fragments of chipping chips.
At this time, the cutting force fluctuations are very large, and concentrated on the cutting edge, easy to damage the tool, and the workpiece surface roughness is also high, therefore, in production should strive to avoid, the method is to reduce the cutting thickness, the chip into needle and sheet, and appropriately improve the cutting speed, in order to increase the plasticity of the workpiece material