Chips

Types of chips in the metal cutting

1. Continuous chip

Continuous chips are formed when the ductile material is machined at high speed and by the smooth flow of the chip up the tool face

Condition of continuous chip formation

• The material should be ductile 
• Small friction between tool and workpiece
• Large rake angle
• Small DOC(depth of cut) 
• High cutting speed

2. Discontinuous chip

Discontinuous types of chips are formed when hard and brittle metals like brass, bronze, and cast iron are machined. 

Small chips are formed due to which friction between tool and workpiece is high.

condition of discontinuous chip formation

• The material should be brittle
• Small back rake angle
• Large feed and depth of cut
• Low cutting speed

3. Continuous chip with Buildup edge

1. This type of chip is very similar to the continuous chip.
2. It is obtained by machining on ductile material. 
3. In this condition of high local temperature and extreme pressure in the cutting and high friction in the tool chip interference.
4. Successive layers of work material are then added to the built-up edge. 
5. When this edge becomes larger and unstable, it breaks up and part of it is carried up the face of the tool along with the chip while the remaining is left over the surface being machined, which contributes to the roughness of the surface. 
6. The built-up edge changes its size during the cutting operation. 

Condition of Continuous chip with Buildup edge formation

• The material should be ductile
• Feed and DOC should be large
• Back rake angle small
• Cutting speed low