技術比較：研削と研磨

Technical Comparison: Grinding vs. Polishing

Dimension	Grinding	Polishing
Core Objective	Correct geometric errors (flatness/roundness), control dimensional accuracy	Enhance surface gloss, eliminate micro-scratches, achieve mirror finish
Processing Principle	Hard abrasive particles (e.g., diamond, silicon carbide) cutting removal	Flexible medium (polishing paste/wheel) plastic deformation & micro-asperity flattening
Material Removal	Micron-level (rough/semi-finishing)	Sub-micron (<0.1μm, finishing)
Surface Roughness	Ra 0.025~0.006μm (ultra-precision down to nanoscale)	Ra 0.01~0.001μm (optical grade <0.5nm)
Equipment/Tools	Grinding wheels/belts/discs (matched abrasive grain size & hardness)	Polishing wheels (wool/polyurethane), polishing pastes (alumina/chromium oxide micropowders)
Process Parameters	High pressure (0.01~0.1MPa), low speed (10~30m/s)	Low pressure (<0.01MPa), high speed (30~100m/s)
Typical Applications	Precision mechanical parts, semiconductor wafer pre-processing, optical element roughing	Optical lenses, decorative parts (e.g., phone cases), high-precision mold finishing

Key Differences

• Material Removal Mechanism:

1. Grinding: Hard abrasive "cutting" (similar to micro-turning).
2. Polishing: Flexible medium "ironing" micro-asperities via plastic deformation.

• Surface Quality:

1. Grinding: Focuses on shape/dimensional correction, achieves Ra ~0.025μm.
2. Polishing: Focuses on optical performance, achieves Ra <0.001μm.

• Process Stage:

1. Grinding: Pre-finishing step, provides base surface for polishing.
2. Polishing: Final finishing step, directly determines final surface quality.