Grinding removes material with many small abrasive cutting points bonded into a wheel or carried in another abrasive tool.

Each grain acts like a tiny cutting edge. Because grain geometry and protrusion vary statistically, grinding is less geometrically deterministic at the individual-edge level than turning or milling, but the large number of active grains can produce fine finishes and accurate dimensions.

Important characteristics include:

• abrasive material and grain size;
• wheel hardness or grade, which describes how strongly grains are retained;
• wheel structure or porosity;
• wheel speed and work speed;
• depth of engagement.

As grains dull, forces and heat can rise. A grinding wheel must periodically be dressed to expose fresh cutting points and restore its cutting surface. Truing restores the intended wheel geometry.

Grinding can generate intense heat in a shallow surface layer. Excess thermal loading can cause burns, residual stress, distortion or local material change even when the final dimension is correct.

A common manufacturing strategy is to create most geometry with a faster roughing process and reserve grinding for surfaces that need its final dimensional or texture capability.

Grinding is therefore not simply 'very fine machining'. It has its own abrasive tool behavior, thermal risks and surface-integrity considerations.