CNC machines utilize computer logic to instruct and inform the design and production of precision parts through the use of computer automated machinery. These advanced devices utilize computer numeric control technology to perform complex machining including the grinding, milling, broaching, cutting and drilling of materials as diverse as metal, wood, glass, ceramic and stone.
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CNC machines vary considerably to include those that contain only one tooling apparatus as well as those that perform up to 400 individual operations. Often smaller machines are operated in conjunction with others, a system known as a cell. Each machine configuration functions in the same manner, beginning first with a computerized design. CNC work utilizes CAM, CAD and other computer engineering programs to develop complex schematics and measurements used to inform the actions of machining equipment. Advanced software translates these dimensions and requirements into a computerized language or code. The raw material, usually in billet or other stock form, is loaded into the lathe. Either the materials or tooling mechanisms are attached to a rotating spindle allowing for increased access and opportunity to perform operations along the entirety of the object. Advanced spindles operate on five axes of motion; they can move up and down, they can move linearly on a horizontal axis and they can pivot and rotate as well. These movements are dictated by the aforementioned code. CNC programming instructs the positioning, pressure applied, depth and all other movements of these automated devices in order to produce high precision identical parts in rapid succession. This process that would take much longer if performed manually.
As computer technology advances, CNC machining advances with it. While these machines were once all custom built, the standardization of modular tooling devices allows machines to be built for stock while still meeting the needs of most operations. Industries taking advantage of this include aerospace, food and chemical processing, automotive and agriculture. Standardization lowers overhead cost and allows for easier replacement of broken components. Despite this reduction in cost, however, CNC machines still entail a substantial purchase. In some instances, the computer or controller is therefore retrofitted to pre-existing devices, though this is not always as efficient as fully integrated machines. For both models, it is important to consider the specific applications of a machine in order to optimize space, material and use. As CNC machining often involves the manipulation of metal, stone and other industrial strength materials, the machines themselves must be made of durable components. Machines must support both the raw material to be processed and the tooling mechanisms themselves, some of which may weigh several hundred pounds. Common materials used in the design of CNC machines are hardened and heat treated metals such as steel, stainless steel and cast iron. The components are welded, bolted and pinned together. Proper installation is essential to safe practices and easy maintenance of machines, which ensures continued usability and accuracy. CNC machines and production should also adhere to the regulations set forth by the International Organization for Standardization, or ISO. Those parameters specifically outlining and defining the expectations of CNC machining include ISO 9001:2000, ISO 13485:2003, ISO 14001 and ISO/TS 16848:2002.
