Gear grinding and fine hobbing are both finishing processes for cylindrical gears, used to improve gear accuracy. But they have some differences in processing, cost and used in different situations.
Gear hobbing is a continuous generating process using a rotating hobbing cutter removes material to form gear teeth. Fine hobbing is simply a high‑precision variant that produce gears with superior surface finish and accuracy directly without subsequent grinding.
Gear grinding, uses a grinding wheel (either a form wheel or a generating wheel) to abrade material from the tooth flanks. It is typically performed after heat treatment to correct distortions after hardening.
Fine hobbing and grinding both can achieve high accuray DIN 6, with high surface roughness.
Fine hobbing with high production efficiency, a single hobbing cutter can run for hundreds of parts, and costs significantly less per piece. Grinding is slower, consumes expensive wheels, requires frequent dressing, and has higher machine and tooling costs.