Built-up edge (BUE) vs. cutting speed How does increasing cutting speed generally affect built-up edge formation on ductile materials during machining?

Introduction / Context:
Built-up edge (BUE) is a wedge of work material that adheres to the tool rake face near the cutting edge, altering effective geometry and degrading surface finish. Speed, rake, and lubrication strongly influence BUE.

Given Data / Assumptions:

• Ductile work material (e.g., steel, aluminum) and a conventional tool.
• All other conditions unchanged while speed increases.

Concept / Approach:
At low cutting speeds, adhesion time and friction are high, promoting BUE. As speed increases, temperature rises and the contact time reduces, decreasing adhesion strength. The BUE tends to diminish and often disappears at sufficiently high speed, improving finish and dimensional accuracy.

Step-by-Step Solution:
Start at low speed → BUE forms readily.Increase speed → less time for adhesion and more thermal softening at the interface.High speed → BUE becomes unstable, breaks off, and may vanish entirely.

Verification / Alternative check:
Toolmaker recommendations often suggest raising speed (within tool capability) or using cutting fluids to combat BUE.

Why Other Options Are Wrong:

• (A) contradicts observed trend.
• (B) ignores well-established dependence on speed and friction.
• (D) speed is a primary parameter affecting BUE; saying “nothing to do” is incorrect.

Common Pitfalls:
Raising speed beyond tool material limits (causing wear), or ignoring rake angle and lubrication, which also influence BUE.

Final Answer:
becomes smaller and finally does not form at all