Machining

Machining is a core material-removal process in manufacturing in which a workpiece is shaped by removing excess material using machine tools. Unlike forming or casting, machining removes material to create precise geometries and features. It encompasses a range of techniques and scales from hand-operated lathes to fully automated CNC systems, and it is widely applied to metals, plastics, and composites.

The most common machining operations are turning, milling, drilling, boring, and grinding. Additional methods include tapping, reaming, broaching, sawing, and non-traditional processes such as electrical discharge machining, laser cutting, and waterjet cutting. The choice depends on the desired geometry, material, tolerance, surface finish, and production volume.

Machining relies on cutting tools made of high-speed steel, carbide, or ceramics, mounted in machines that provide controlled motion. Key factors include tool geometry, cutting speed, feed rate, depth of cut, and workholding quality. Computer numerical control has expanded capability, enabling complex 3D geometry with repeatable tolerances.

Tolerance and surface finish vary with process and tooling; typical general-purpose machining can achieve around ±0.05 to ±0.1 mm, with finishing passes achieving finer finishes. Machining requires coolant or lubrication to control heat and chip evacuation, and proper safety practices are essential to protect operators from chips, sparks, and moving parts. Environmental considerations include energy use and coolant management.