Difficulty: Easy
Correct Answer: Negative rake angle
Explanation:
Introduction / Context:
Rake angle influences cutting forces, edge strength, and heat distribution. Carbide-tipped tools, with high hot hardness but limited toughness compared with HSS, often use negative rake geometry for durability at high speeds and heavy cuts.
Given Data / Assumptions:
Concept / Approach:
Negative rake geometry thickens the wedge angle, increases edge strength, and places the cutting load more in compression, which carbides tolerate well. While positive rake reduces forces, it thins the wedge and can chip at high loads or interrupted cuts.
Step-by-Step Solution:
Verification / Alternative check:
ISO insert geometries and chipbreaker designs frequently feature negative basic rake with engineered chip grooves to moderate cutting forces.
Why Other Options Are Wrong:
Positive rake is used for low-power machines and gummy materials but compromises edge strength. Zero rake is sometimes used, but not the typical choice for robustness across conditions. Exotic alternating rake edges are impractical.
Common Pitfalls:
Applying negative rake on a flimsy setup can induce chatter; ensure sufficient rigidity and appropriate feeds/speeds.
Final Answer:
Negative rake angle
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