CNC Plasma Cutters use a computer and a special coding language called G-code to program projects. The cutter then carries out the cuts you desire. This type of machine can increase your productivity by 1000% or more. So, what are you waiting for? Oh right! You want to know what to look for when you are buying one.
Recent improvements in technology and manufacturing have created an excellent buying environment. Plasma cutters are cheaper than they ever were and they are also more advanced than ever before.
First, you will want to be familiar with the plasma cutting process, since this will help you understand the different ways to classify plasma cutters. If you know your way around a plasma cutter already, feel free to skip the next paragraph.
In order for plasma cutting to work, plasma has to be created. Inside a plasma cutting torch, plasma is created by firing an electric spark into the torch nozzle while pressurized gas (often air) surges out of the nozzle onto the metal to be cut. The spark heats the gas to 15,000 degrees Celsius at which point the gas turns into plasma. Plasma is the fourth state of matter; it is both a liquid and a gas at the same time (this is analogous to how visible light is a wave and a particle at the same time). The electrical spark is created when the plasma cutting torch is touched to the cutting surface. This closes an electric circuit between the plasma cutting machine and the work piece.
Automated plasma cutting machines come in two flavors: conventional and precision. These classifications are based on the properties of the cutting flame. Conventional plasma cutting systems are slower than precision systems and they produce more kerf (the volume of metal cut out) and bevel. Being the superior system, precision plasma cutting equipment costs considerably more.
Buyer beware, manufacturers often mismatch power sources and machines. The machines come in two parts: the base machine (with the table, computer terminal and bridge or gantry) and the plasma cutter (precision or conventional). The power sources for those two components are separate and they have to be matched properly. The mismatches are often the manufacturer's fault, but you the buyer have to keep your eyes open to make sure that it does not happen. In the event that you do have mismatched hardware, do not start running it because what will ruin the machines. Contact the company where you bought the equipment and figure out a solution to the problem.
Today's automated plasma cutter market is dominated by two different models of machine, bridge style and gantry style machines. And the machines are generally made from two types of metal, steel (fabricated) or aluminum (extruded). The extruded aluminum machines are "light duty" and they are found in the realm of the artist and the hobbyist. They are best for doing limited amounts of cutting on thinner metals. The industry-strength machines are the ones made from fabricated steel; they can cut continuously all day as well as devour thick metals.
You will want to decide what sort of drive system you need for your projects. If you are a hobbyist or artist, using a conventional machine, a single-side drive system should be all you need. You may also consider a single-motor, dual-side drive system. The higher level drives increase precision which is not what conventional plasma cutters are built for so you would be throwing your money away if you bought higher-level drives. A precision plasma project will require a dual-side two-motor drive system to reach optimum performance.
You will have to think about what size of motor and gear box you require. If the mass of the motor and gear box are too small compared to the mass of the machine then the motor will not be able to effectively change the direction of cutting. This is important when the cuts go back and forth at high speeds. If the masses are not matched properly it will lead to unimpressive cut results and increase wear on the machinery, which may lead to premature failure.