Semifinishing

Semifinishing is a stage in manufacturing and fabrication where a part is moved from an intermediate or rough form toward near-final dimensions, tolerances, and surface characteristics, but has not yet undergone the final finishing operations. The purpose is to remove remaining excess material, correct dimensional deviations, and condition the surface so that the final finish can be applied more reliably and efficiently.

In metalworking, semifinishing often follows rough machining such as turning or milling and precedes precision finishing steps like grinding, polishing, or lapping. Common semifinishing tasks include deburring, face and edge finishing, surface conditioning, light polishing, and heat treatment or stress relief when required. In other industries, such as woodworking or plastics processing, semifinishing likewise refers to preparatory shaping and conditioning before the final sanding, coating, or surface treatment.

Practices and technologies used in semifinishing are chosen to balance dimensional accuracy, surface quality, tool wear, and production throughput. Measurements of tolerances and surface roughness (for example, using profilometry or calipers) guide the process and determine readiness for final finishing. The semifinished state is typically characterized by looser tolerances and a rougher surface than the final specification, allowing for defect detection early in the production sequence.

Overall, semifinishing serves as a bridge between initial forming and final finishing, helping to ensure that final operations are efficient, consistent, and capable of meeting strict quality requirements.