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Saturday, November 29, 2008

CNC Plasma cutter overview

CNC Plasma Cutter Overview
The plasma arc cutter process has been in existence for over 50 years and was created during World War II. At that time the government needed a welding process that would weld together aircraft parts in a better way than what they were using. This process used inert gas that acted as a barrier to protect an electric arc that stopped oxidation from forming on the weld.

As this process was improved over time, people experimented with the openings in the arc to see how they could create the best way for the process to be done. It was also found that if the opening where the inert gas passed through was restricted it would make a hotter flame. On the other hand, if the opening was made smaller, they could also speed up the flow.

CNC Plasma Cutter
All of this experimentation led to the development of a plasma-arc cutting process and this process began to be used on a commercial basis in the early 1960s. However, it was a very expensive process for many businesses to take on.

Today, the process has improved dramatically and there are even plasma cutters that are portable; some models even have air compressors build in for a fuller portability. Many are smaller and are able to cut sheet metal as their primary work but others can output a lot more in voltage and in work. Also as the CNC plasma cutter was created the process could be totally automated; all an operator has to do is key in how they want the plasma cutter to cut and it does the cut perfectly every time.

CNC plasma cutters come in a variety of sizes but they all basically work the same way. The process sends a gas that is pressurized through a channel. The gas could be argon, oxygen or nitrogen that is sent through this channel. Inside the channel is an electrode that is negatively charged. When power is applied to the electrode and the tip of the plasma cutter is touch to the metal, it creates a full circuit.

At this point this circuit makes a high powered spark that goes through the channel; the gas is heated to a very high heat called the fourth state of matter. When this happens a direct stream of plasma turns the metal into molten slag. What this means is that you have a very high heat and a very fast moving beam of light that hits the metal.

The plasma is what makes the electrical current and this power supply keeps working until the circuit between the electrode and the power supply is broken. Also the cutter nozzle has channels in it so that it can continue to create a consistent flow of shielding gas. This also allows the plasma beam to stay consistent on the metal to be melted.

Some CNC plasma cutters have robotic arms that do the work. The point to having this in the CNC mode is that the process is totally automated and it will continue to work to cut with precision as long as the information is programmed correctly into the computer.

Wednesday, November 5, 2008

PLASMA METAL ART

Plasma metal art and the basics of plasma metal art
Plasma cutting is a process by which a compressed gas is blown onto a metal surface. An electric arc is created which raises the gas to extremely high temperature – hot enough to cut through metal very quickly. The force of the gas is able to blow away any molten slag that may have collected on the cut surface, leaving a very clean edge. Since the compressed gas can be focused to a fine point, highly accurate cutting to create intricate shapes and designs can be done.
The origins of plasma cutting can be traced back to the days of World War II and the need to increase the speed and quality of aircraft production. Plasma welding was developed to cut the time taken for the fabrication of body parts and had the advantage of producing stronger joints than conventional welding techniques of the time.
CNC Plasma - Metal Art
In the 1960s this technology was improved by new method of increasing the gas temperature and more finely focusing the stream of gas to allow the plasma stream to be used to cut through metal like a knife, with great accuracy. For industrial applications, large plasma cutters are operated by computers to produce high precision cutting in large volume.
Artists use hand held plasma cutter for their work. These small yet powerful units can be wielded like a knife and can be used to cut through metal to produce intricate shapes and designs. Think of a sheet of metal as a blank canvas and the plasma cutter as the brush. Either by free hand or by using a stencil, the artist cuts through the sheet metal to create the design or art work he wants. Once the cutting is done, the artist can use the equipment to carve out delicate features or create etchings on the surface of his creation. Bending some of the surfaces can be done to add a three dimensional effect.
Since plasma cut sheet metal is thin and delicate by nature, it cannot be used under extreme conditions like large sculptures or as load bearing works of art. The main application is to use this technology to create mirror and picture frames, table top ornaments and other such decorative items. Unlike large pieces of metal art, those created by plasma cutting need to be protected from the elements and are meant for indoor use.
When buying plasma metal art, it needs to be kept in mind that the cost of the material used and the production process makes up only a minor part of the total cost. Except in the case of certain very expensive alloys, sheet metal in not very costly and the cost of using a small hand held plasma cutter is relatively cheap. The value of plasma art likes in the quality of the art – the concept and design, the quality of the production and the fineness of the detail incorporated into the work.
A search of the internet will reveal the vast variety of plasma metal art available – from the reasonably priced to the prohibitively expensive. Just about any kind of decorative metal art can be made by the plasma cutting process and if a buyer has something special in mind, finding an artist who will create what the client wants is not a problem.

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