INTRODUCTION
Plasma cutting is used to cut steel and other metals of different thicknesses using a plasma torch. In this process, an inert gas (in some units, compressed air) is blown at high speed out of a nozzle; at the same time an electrical arc is formed through that gas from the nozzle to the surface being cut, turning some of that gas to plasma. The plasma is hot enough to melt the metal being cut and moves fast enough to blow molten metal away from the cut.
CNC (computer numerical control) Plasma Cutting has been around for 30 years, but only in the past decade has it become affordable enough for the small shop.
The plasma cutting process itself is capable of almost surgical precision. It is the human hand that guides a manual plasma cutting torch that is responsible for the roughness sometimes seen in plasma cut pieces.
Today's CNC plasma cutting systems typically use the operator's personal computer to create the shapes to be cut and control the cutting machine. The resulting shapes are smoother than would be possible with a bandsaw, and can include intricate curves, inside cuts, and sharp corners.
WORKING
Plasma cutters work by sending an electric arc through a gas that is passing through a constricted opening. The gas can be shop air, nitrogen, argon, oxygen. etc. This elevates the temperature of the gas to the point that it enters a 4th state of matter. We all are familiar with the first three: i.e., solid, liquid, and gas. Scientists call this additional state plasma. As the metal being cut is part of the circuit, the electrical conductivity of the plasma causes the arc to transfer to the work.
The restricted opening (nozzle) the gas passes through causes it to squeeze by at a high speed, like air passing through a venture in a carburetor. This high speed gas cuts through the molten metal. The gas is also directed around the perimeter of the cutting area to shield the cut.
.
ADVANTAGES
Plasma is an effective means of cutting thin and thick materials alike. Hand-held torches can usually cut up to 38mm thick steel plate, and stronger computer-controlled torches can cut steel up to 150 mm thick. Since plasma cutters produce a very hot and very localized "cone" to cut with, they are extremely useful for cutting sheet metal in curved or angled shapes.
- [Accuracy and Precision] The cutter is designed with gears that enable the plasma cutter with accurate motions in all the directions of cutting such that there are no variations on the measurements.
- [Efficiency] One of the aspects of efficiency in CNC plasma cutting lies in the ease of use of the cutter. The cutter requires minimal training for the operator which makes using it very efficient.
- [Variety] CNC plasma cutting can be applied to a variety of materials.
DISADVANTAGES
- [Hardened Edges] The plasma will develop a heat influenced zone and harden the edges of the materials getting slice.
- [Dross] Most plasma slice components will have some dross that wants to be cleaned from the part but this has been minimized with today's substantial overall performance plasma chopping techniques
- [Cost ]CNC plasma cutters can price much more.
Category:
