Types of chips used in metal cutting

Introduction

Metal cutting is crucial in industries like automotive, aerospace, manufacturing, and construction, with chip formation being a key aspect. Knowledge of chip types is essential for efficient machining and optimal results. This blog will explore chip types in metal cutting and their importance in various applications.

Types of Chip Formation

Various types of chips, which are formed in various cutting conditions and type of machining, can be categorized as follow:

Continuous chip
Discontinuous chip
Continuous chip with built-up edge
Serrated chip

1.Continuous Chip

Continuous chips, also called long chips or ribbon chips, are created when the cutting tool stays in constant contact with the workpiece. These chips are frequently seen when machining ductile materials like aluminum and copper, and are distinguished by their long, smooth, and evenly thick appearance. Machinists strive for continuous chips as they signal a consistent cutting process and help achieve a polished surface on the workpiece.

Continuous chip, as shown in Figure 1, is formed due to

Machining of ductile materials
Small undercut thickness
High cutting speed
Large rake angle of the tool
Suitable cutting fluids

Explore the different types of chip formation and gain insights into continuous chip on our informative website

Figure 1

2.Discontinuous Chip

Segmented chips, also known as broken or discontinuous chips, are created when the cutting tool makes intermittent contact with the workpiece. These chips are often seen in brittle materials like cast iron and specific alloys. They are shorter in length and may look like fragmented pieces. Despite being harder to handle, especially in terms of disposing the chips, they can be beneficial in reducing tool wear and maintaining a controlled machining process.

Discontinuous chip, as shown in Figure 2, is formed due to

Machining of brittle work materials
Low cutting speed
Small rake angle
Large uncut chip thickness

Figure 2

3.Continuous Chip with Built-up (BUP) Edge

Continuous chip with built-up edge is not an actual chip, but a result of metal cutting affecting chip formation. It occurs when workpiece material sticks to the cutting tool, impacting surface finish. Proper management is essential for cutting efficiency and workpiece accuracy.

Continuous chip with built-up edge, as shown in Figure 3, is formed due to

Large friction or stronger adhesion between chips and tool face
Low rake angle
Large uncut chip thickness

Figure 3

4.Serrated Chip

Serrated chips, also called saw-toothed chips, have a zigzag pattern on their edges. They are commonly seen in materials of different hardness or during intermittent cutting. Controlling serrated chips can be difficult, resulting in issues like bad surface finish and higher tool wear. Knowing the factors that cause serrated chips is crucial for improving machining settings.

Serrated Chip, as shown in Figure 4, is formed due to

High temperature at contact surface between cutting tool and workpiece

Figure 4

Conclusion

In the metal cutting industry, the chips produced can give important information about how well the machining is working. Machinists need to think about things like the material being cut, cutting settings, and tool choice to get the right kind of chips. Knowing about different chip types is important for successful metal cutting.