In metal cutting and machining processes, there is no how chip production can be escaped. These chips can occur in various forms leading us to their types. Many factors determine the types of chips to obtain in the metal cutting process, which I will further elaborate on.
Our aim here today is to explain the definition, purpose, and different types of chips in metal cutting or machining processes. We will also get to know the various factors that determine the types of chips that will obtain during the process. You’ll also get to know the advantages and disadvantages the chips types machining process offers.
Read more: Understanding lathe machine
- 1 What are chips?
- 2 Factors that determine the types of chips to be produced
- 3 Types of chips
- 3.1 Discontinuous chips:
- 3.2 Continuous chips:
- 3.3 Continuous chips with a built-up edge:
- 3.4 Join our Newsletter
- 4 Comparison between the three types of chips in tabular form:
- 5 Conclusion
What are chips?
Chips are materials removed from a workpiece with the aid of tools. Chips are formed during machining processes and are produced by shearing. As a cutting tool mounted to a machine engages the workpiece, the material ahead of the tool is shear and deformed under tremendous pressure. This deformed material tends to relieve its stressed condition by fracturing and flowing above the tool in the form of a chip.
The purpose of some chips is for business. Coiled SS chips are used for scrubbing and cleaning household utensils.
Factors that determine the types of chips to be produced
Below are the factors that determined the types of chips produce during a machining process:
- The material used as the cutting tool
- Dimension of the tool.
- Materials used as workpiece
- Speed of cutting.
- Forces applied during the cutting process.
- Friction between the workpiece and tool.
- Cutting environment such as temperature.
Types of chips
Below are the various types of chips in metal cutting or machining processes:
These types of chips are small segments that adhere loosely to each other and form a slightly larger length. They are formed when the amount of deformation the chips undergo is limited due to fracture repeatedly. The segments are formed regularly due to the rupture of the metal ahead of the tool.
Discontinuous chip types in ductile materials are produced because the hydrostatic pressure near the cutting edge is tensile or the shear energy reaches a critical level. Although the formation of this chip in brittle materials offers a good finish, increases tool life, and consumes less power. In ductile materials, these chip types may result in poor finish and excessive tool wear. However, smaller chips can be disposed of.
While machining hard and brittle metals like bronze, brass, and cast-iron, discontinuous chips are obtained. Sometimes, cutting of ductile metals at very low feeds with a small rake angle of the cutting tool and high speeds and high friction forces at the chip tool interface also result in the production of these types of chips.
Advantages and disadvantages of discontinuous chips
Below are the benefits of discontinuous chips on brittle materials:
- Increases tool life
- Good surface finish.
- Reduces consumption of power.
Below are the limitations of discontinuous chips on ductile materials:
- Poor surface finish.
- Excessive wear and tear of the tool.
In a continuous chip formation, the pressure of the workpiece builds until the material fails by slip along the slip plane. In these types of chips, the metal chips are formed during machining without segments, that is, without breakage. It can be formed when ductile material is machined with high cutting speed and minimum friction between the chip and tool face. Ductile material such as mild steel is better.
Advantages of continuous chips
Below are the advantages of continuous chips during the machining process:
- Offers better surface finish to ductile materials.
- Low power consumption.
- Less heat generation is due to minimize friction between the chip and tool face.
- Less wear and tear, resulting to longer tool life.
Continuous chips with a built-up edge:
When a ductile material is machined with high friction at the chip tool interface, a continuous chip with a built-up edge is formed. These types of chips are similar to the continuous chips but their smoothness is less due to the built-up edge.
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The built-up edge is formed when the chip flows in an upward direction and high friction exists between the interface of the chip and tool. This high friction between the tool and chip causes intense heat to be generated at the nose of the tool. The compressed metal adjacent to the tool nose gets welded to it. This compressed metal welded to the nose is what we called a built-up edge.
Continuous chips with built-up edge are attained at excessive feed rate, the small rake angle of the tool, low cutting speed, and lack of coolant, which increases the friction between the chip tool interfaces.
Advantages and disadvantages of continuous chips with built-up edge
- The tool is protected from getting damaged from high friction and temperature generated during the process.
- The tool life is increased.
- A rough surface finish is obtained.
- Change in rake angle and cutting forces.
Comparison between the three types of chips in tabular form:
|Continuous chips with Built-Up Edge (BUE)|
|1.||Material types||Ductile||Brittle, ductile but hard||Ductile|
|3.||Cutting speed||High||Medium or high||Low or medium|
|4.||Friction between chip tool
|5.||Depth of cut||Small||High||Medium|
Watch the video below to learn more about the various types of chips in the metal cutting and machining process:
Chips are materials removed from a workpiece with the aid of a tool. They are reprocessed to serve other purposes. That is all for this article where we’ve explained the various types of chip and their advantages and disadvantages.
I hope you get a lot from this post, if so, kindly share with other students. Thanks for reading, see you next time!