Plasma cutting system of CNC plasma cutting machine includes the components: power supply, arc starter circuit, specialized cutter. The power supply system, ionization capability and control system role a key play in creating productive processing and sharp product on any different metal materials.
Image of standard CNC plasma cutting machine
Plasma metal cutting technology
It is unbelievable to use gas to cut metal, however, plasma metal cutting technology makes it possible. The gases commonly are used in plasma cutting such as air, oxygen, nitrogen, which do not conduct electricity in a normal environment. Though, when providing them with enough energy to ionize gas atoms, they become electrically conductive. The oxidation process is extremely powerful with energy is continuously supplied, the gas stream will convert into plasma flow, also known as plasma.
- The power supply is a DC source that has voltage from 240-400 VDC. The output of the power supply role is to determine the speed and thickness of the material to be cut. The main function of a power source is to provide accurate and continuous power to maintain plasma arc after ionization.
- Starting arcing circuit emit high-frequency, which creates an AC voltage of 5000 to 10000V at an extremely large frequency of about 2 million HZ. Thanks to this voltage, the gas is easily ionized and produces a high-intensity arc inside the plasma cutter head.
- The cutting head works to keep consumable parts such as nozzles and electrodes, providing cooling to these parts. Nozzles and electrodes work to compress and maintain plasma rays.
Operation of CNC plasma cutting machines
The power supply and the starting arc circuit are connected to the cutting head with internal pipes and wires. Pipes and conductors provide gas flow, electric current, starting arc current in accordance with the cutting head to bait and maintain the cutting process.
1. First, the source receives a starting signal and activates the voltage of 280 VC, then the gas stream is transferred to the cutting head. Air flows through the nozzle and goes out. There is no arc current as well as electric current flowing through the DC current at this moment.
2. After the gas flow has run smoothly, the starter arc circuit begins working with 5000 – 1000VAC at high frequency, sparks are fired between the electrode and the nozzle inside the cutting head. The gasoline flow receives high energy from the sparks causes it to become ionized and become electrically conductive. This gas flow becomes the electrical path between the electrode and the nozzle forming a plasma arc. The arc along the air flow to the outside of the nozzle forms a stream of primer arc flow.
3. When the nozzle is moved close enough to the cutting material, the primer stream will strike the material as an electrical path to the anode of the power supply without being limited by resistors like the nozzle connected to the anode. The power source identifier runs through the material, at which time the arc starter stop working and the ionizing gas flow continues to be maintained by the energy of the DC current.
4. High-temperature plasma arc will melt metal material and break them. High-speed airflows will blow molten material to the bottom of the cutting line. At this time, the cutting head starts to move, and the metal cutting process begins.
5. At that time, the CNC cutting machine will move and cut the material according to the drawing. The cutter controller also starts working to adjust the cutting head up and down in accordance with the distance of the material when the material is bent or warped. This operation ensures the product is properly cut according to the drawing while the cutting head also is protected.