Machining is the general term referring to any of various processes in which metal in its raw material form is cut via a controlled material-removal process into either a part or a semi-finished part. The many processes that have this common theme, controlled material removal, are also known as subtractive manufacturing. Exactly what the "controlled" part of the definition implies can vary, but it almost always implies the use of machine tools and fixtures which are able to hold tolerances far tighter and produce parts far faster than manual processes.
Networks of machine shops abound within the industrial markets, either producing end products or supporting the production process of large original equipment manufacturers (OEMs) fabrication needs. Castle Metals works cooperatively with machine shops and OEMs who are looking to:
- Expand overloaded production processes
- Re-deploy manpower from non-core processes to higher value-added processes
- Free cash flow by reducing work-in-process inventory and idle manufacturing assets
The principle machining techniques can be reduced into three key processes, turning, milling, and drilling. Turning operations rotate raw material against the cutting tool as the primary method of removing metal. Lathes are the principal machine tool used in turning. Milling operations are operations in which the cutting tool rotates to bring cutting edges to bear against the metal. Milling machines, or mills, are the principal machine tool used in milling. Drilling operations are operations in which holes are produced or refined by bringing a rotating cutter with cutting edges at the lower extremity into contact with the work piece. Drilling operations are done primarily in drill presses but sometimes on lathes or mills.
Machining techniques that are growing in importance to customers include computer numerical control (CNC) machining, trepanning and boring.