Fundamental mechanism of chip formation in machining In metal cutting operations (turning, milling, drilling), chips are formed primarily due to which material behavior?

Introduction / Context:
Understanding how chips form is central to machining science. Chips separate from the workpiece along a shear plane under significant compressive and shear stresses at the tool–work interface. This behavior determines forces, temperature, surface integrity, and tool wear.

Given Data / Assumptions:

• Conventional cutting with sharp tools at typical speeds.
• Homogeneous metallic work material.
• No special processes like EDM or laser cutting.

Concept / Approach:
Chip formation is governed by plastic deformation. Material ahead of the cutting edge is forced to shear along a narrow zone (primary shear zone). Elastic deformation occurs first but is small; once yield is exceeded, plastic deformation accommodates chip flow over the rake face.

Step-by-Step Solution:
Tool engages work; stress builds ahead of the tool.Material yields and shears plastically along a shear plane.Chip slides over the rake face with secondary deformation and frictional heating.After removal, elastic recovery affects the final machined dimension slightly.

Verification / Alternative check:
Metallographic examination shows severe plastic strain and heat-affected bands in chips. Specific cutting energy models also assume plastic work plus friction work.

Why Other Options Are Wrong:
Elastic spring-back alone cannot separate material. Pure thermal softening or phase change alone does not describe mechanical chip formation in conventional cutting. Thus, “Disagree” is incorrect.

Common Pitfalls:
Overlooking the role of friction and secondary deformation; assuming material “melts” during normal cutting—it generally does not, despite high temperatures.

Final Answer:
Agree