| Plasma cutters cut metal using a plasma torch. For it | | | | plasma torch touches the material to be cut, thereby |
| work, plasma (the fourth state of matter) has to be | | | | closing the circuit, the spark fires into the torch head |
| created. Plasma is a super-heated (15,000 degrees | | | | and plasma is created. |
| Celsius) substance that is a gas and a liquid at the | | | | 2. Pilot Arc. This method is a little more involved since it |
| same time. Two things are required to create plasma, | | | | produces plasma in two cycles. Cycle one: inside the |
| a gas and a heat source. | | | | body of the torch a low current, high voltage circuit |
| Plasma cutters use inert gases (often compressed air) | | | | creates a high intensity spark. This spark creates a |
| and electricity to create plasma. The plasma cutting | | | | small volume of plasma (the pilot arc). Cycle two: the |
| equipment is set up so that it creates an electric circuit | | | | pilot arc remains static until the torch head is touched |
| with the metal that is being cut. When the end of the | | | | to the metal at which point a trigger allows the pilot arc |
| torch is touched to the metal, the circuit is created and | | | | to light the main flow of gas and plasma cutting begins. |
| a spark flashes through the nozzle of the plasma | | | | The old versions of plasma cutters (plasma cutting |
| torch. This spark travels to the negative electrode in | | | | was invented during World War II) started the arc with |
| the torch handle and meets with the rapidly flowing | | | | high frequency, high voltage circuits. This means that |
| inert gas. When the gas comes into contact with the | | | | the operator risked electrocution if they were not |
| electricity it is heated to around 15,000 degrees Celsius | | | | careful. Also, these old machines are difficult to repair |
| and becomes plasma. The plasma surges out of the | | | | and maintain. |
| tiny nozzle and onto the surface that you want to cut. | | | | A plasma cutter can cut metals of different |
| The tiny opening in the nozzle focuses the plasma | | | | thicknesses. The size of the machine is what |
| flow and causes it to speed up. It is the speed, | | | | determines the sever cut. "Sever cut" is the standard |
| temperature and focus of the plasma that enables it to | | | | used to define the thickest possible cutting potential for |
| cut metal almost as well as a laser. | | | | a given plasma cutter. The thicker the metal to be cut |
| As long as everything is set up properly, the cuts can | | | | the easier it is for a CNC plasma cutter to operate. |
| be very clean with little noticeable affect on the rest of | | | | You have to watch out though, the closer the metal |
| the work piece. | | | | thickness comes to the sever cut rating of a plasma |
| Since a plasma cutter's function requires an electric | | | | cutter the messier the cut may be. This means you |
| circuit they can cut pretty much anything that conducts | | | | may have to clean up the edges after you are finished |
| electricity including copper, aluminum and stainless steel. | | | | cutting. |
| There are two methods used to create the plasma | | | | Since CNC plasma cutters are computer controlled |
| for plasma cutting. | | | | they are very precise. For very repetitive projects or |
| | | | industrial applications a CNC plasma cutter is must. |
| 1. HF (High Frequency) Contact. This method is | | | | These machines can do the same thing over and over |
| generally used in low budget equipment since it cannot | | | | and over all day long. |
| be used for CNC (Computer Numeric Control) Plasma | | | | When you are using plasma cutters please make sure |
| Cutting operations. To generate plasma, this method | | | | that you follow safety guidelines. |
| uses a high frequency, high voltage spark. When the | | | | |