Gear finishing processes: What is gear burnishing primarily used for in manufacturing practice?

Introduction / Context:
After gear tooth generation (hobbing, shaping), finishing processes improve surface texture, contact pattern, and noise performance. Burnishing is a chip-less cold working technique performed with hardened gear-like tools.

Given Data / Assumptions:

• Process occurs after basic tooth form exists.
• Burnishing tools are harder than the work gear and roll in mesh.
• No abrasive is used; the method relies on plastic deformation at asperities.

Concept / Approach:
Burnishing smooths the flanks by plastically deforming surface peaks into valleys, reducing roughness, improving bearing area, and sometimes inducing beneficial compressive stresses near the surface for better pitting resistance.

Step-by-Step Solution:

Verification / Alternative check:
Surface measurements before/after show reduced roughness; tooth contact analysis indicates improved pattern and load distribution.

Why Other Options Are Wrong:

• Under-cut gears and cycloidal gears describe geometry, not a finishing process.
• Residual stress removal is linked to thermal stress relief; burnishing typically adds near-surface compressive stress rather than removing it.

Common Pitfalls:
Confusing burnishing with lapping or honing (abrasive methods). Burnishing is chip-less and relies on plastic flow.

Final Answer:
Surface finishing