CNC is a major trend in metal and other types of fabrication. It stands for Computer Numeric Control. It is a computer-controlled input method for a variety of machines, including plasma cutters. Plasma cutters use a unique method to liquify and cut through metal with the fourth state of matter: plasma. Most plasma cutters are hand-held. But, they are ideal from high-output, repetitive and consistent cuts when joined with a CNC system. Here are the components of a CNC actuated plasma cutter. The Plasma Cutter The tip of a CNC actuated plasma torch works the same as hand-held units. The nozzle directs an electrode, cutting gas, shielding gas and the subsequent plasma. Though on CNC actuated devices it has flexible hoses arranged such that they will not interfere at any point in the full operating range of the machine. Conceptually, a CNC plasma cutter could function in three-dimensions like a robotic spot-welder; in practice, most function in two-dimensions, on an X and Y axis, very similar to a plotting machine. Table and Armature The table must accommodate metal to be cut. It's often made of steel and configured into a grate. The grate holds material flat, but stands up to plasma blowing through a removing some of the table material. The tables are generally modular as they have to be replaced from time to time. The armature, like a plotting machine is usually made of two straight arms that can move simultaneously. The plasma cutting tip is mounted at the intersection of the X and Y axis. Each arm is motor-driven. The CNC input can fluidly move the cutting tip along any shape it's programmed to cut. It can cut something as simple as a perfectly straight line, or a very sophisticated computer-designed shape. The Computer and Software The CNC component has the same components as any basic computer: a microprocessor, memory and data storage. In fact, some CNC devices are attached to and controlled by PCs. The software and the computer hardware create an environment in which the an operator can feed them instructions in the form of a CNC program. The program defines shapes and sequences for the CNC to cut. CNC "Program" or Design For a CNC system to function, once it setup with cutting torch, table, armature, and computer, it needs to be given instructions. The two-dimensional designs are usually designed on a computer, but can be designed in other environments, then scanned into a computer. They are translated into a specific machine language the CNC software can interpret. Then, when told to execute the program, the device cuts the shape(s) out of whatever metal stock is placed on the table. Source: ehow.com
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