A machine shop or engineering workshop (UK) is a room, building, or company where machining, a form of subtractive manufacturing, is done. In a machine shop, machinists use machine tools and cutting tools to make parts, usually of metal or plastic (but sometimes of other materials such as glass or wood). A machine shop can be a small business (such as a job shop) or a portion of a factory, whether a toolroom or a production area for manufacturing. The building construction and the layout of the place and equipment vary, and are specific to the shop; for instance, the flooring in one shop may be concrete, or even compacted dirt, and another shop may have asphalt floors. A shop may be air-conditioned or not; but in other shops it may be necessary to maintain a controlled climate. Each shop has its own tools and machinery which differ from other shops in quantity, capability and focus of expertise. The parts produced can be the end product of the factory, to be sold to customers in the machine industry, the car industry, the aircraft industry, or others. It may encompass the frequent machining of customized components. In other cases, companies in those fields have their own machine shops. The production can consist of cutting, shaping, drilling, finishing, and other processes, frequently those related to metalworking. The machine tools typically include metal lathes, milling machines, machining centers, multitasking machines, drill presses, or grinding machines, many controlled with computer numerical control (CNC). Other processes, such as heat treating, electroplating, or painting of the parts before or after machining, are often done in a separate facility. A machine shop can contain some raw materials (such as bar stock for machining) and an inventory of finished parts. These items are often stored in a warehouse. The control and traceability of the materials usually depend on the company's management and the industries that are served, standard certification of the establishment, and stewardship. A machine shop can be a capital intensive business, because the purchase of equipment can require large investments. A machine shop can also be labour-intensive, especially if it is specialized in repairing machinery on a job production basis, but production machining (both batch production and mass production) is much more automated than it was before the development of CNC, programmable logic control (PLC), microcomputers, and robotics. It no longer requires masses of workers, although