machined

Machined describes parts produced by removing material with machine tools, a subtractive approach used to achieve precise geometry and smooth finishes. Machining applies to metals, plastics, and composites and is typically contrasted with forming processes such as casting, forging, or molding. Some parts may require both forming and subsequent machining.

Traditional machining includes turning, milling, drilling, boring, tapping, and grinding. These operations are performed on machine tools such as lathes, milling machines, drill presses, and grinders, and increasingly under computer numerical control (CNC) to deliver tight tolerances and consistent quality. In addition to conventional methods, non-traditional or advanced processes such as electrical discharge machining (EDM), wire EDM, laser cutting, and waterjet may be used for hard materials or complex geometries.

Tooling options, materials, and process parameters influence tool life and surface finish. Cutting tools often use carbide or high-speed steel, with coatings like TiN or TiCN. Typical finished part tolerances range from ±0.005 inches (0.127 mm) for general work to ±0.001 inch (0.025 mm) or better for precision parts; surface finishes can range from rough Ra around 3.2–6.3 µm to finer levels with finishing passes.

Post-processing steps such as deburring, heat treatment, coating, or plating are common. Metrology, including calipers, micrometers, and coordinate measuring machines (CMMs), verifies dimensions and form. Standards such as GD&T guide allowable variations.