The production of a work piece involve transforming a bank of raw piece from its original state to a finished state by changing its shape or the properties of the material in a series of steps. When no further changes have to be made. It is known as a finished piece or finished part.
The classification of production processes starts from the concept of coherence of the material particles or coherence of the structural elements.
Primary forming consists of making a solid body out of formless material. Included in this category as casting of metals, ceramics and plastic, pressing metal powders and subsequently sintering them, pressing synthetic resins, the production of work pieces by electrolytic deposition.
Reshaping consist of changing the shape of a solid body without adding or removing material (plastic transforming). This category includes remodeling by pressure (extrusion, molding, forging, rolling), by tension and compression (deep drawing wire drawing) by tensile reformation (stretch forming) and by bending.
Changing the properties of the material by reorienting the material particles. This include process in which the internal structure of the material is changed, e.g. tempering, hardening, solid rolling and magnetization.
Cutting is means of reshaping a solid body by overcoming is coherence. Distinctions are made between: dividing, e.g. cutting off, incising, tearing; chip removal (machining), e.g. turning, drilling, grinding, filing, sawing, wearing off material by heal (e.g. torch cutting); separation of previously joined work pieces, e.g. unscrewing, squeezing out: Cleaning of work pieces by brushing, sand blasting, washing, picking.
The group also includes the elimination of material particles, e.g. decarburizing steel. Joining consists of bringing together work piece by combining (insertion and suspension, by adjusting and fitting (wedging, screwing, shrinking) by primary shaping (remolding), deforming, (folding together, wrapping, riveting) by material bonding (welding, soldering, use of adhesives).
Adding material particles, e.g. nitrogen, changes the properties of basic material. Coating consists of spreading a coat of formless material that adhered to the surface of the work piece (painting), vapor depositing, and deposit welding, galvanizing, thermal spraying.