What is plasma?
History of plasma cutting technology dates back to the 1950s. To understand how it works, it is crucial to familiarize yourself with the basic elements of this process. Plasma arc is ionized matter that is in a gas-like state. Combination of ions with different charges and free electrons make plasma a good current conductor, but its resistance decreases with increasing temperature. Intensity of the flowing current in the plasma allows to distinguish three states. There is no noticeable light (black current) during low current. As the intensity increases, the plasma begins to generate light to form a plasma arc at the climax. This is what is used during the CNC plasma cutting process.
What does a material processing plasma system consist of?
Different types of gases are used in the plasma cutting process. In the case of basic devices, it is air, but high-power devices (High Definition plasma) require the use of: oxygen, azote, hydrogen, argon or mixtures of these gases. Each of these gases is used as needed:
- Oxygen – used to process low-carbon and low-alloy steels
- Azote – used to mark and cut non-ferrous materials
- Argon – used to plasma marking
- Argon-hydrogen and azote-hydrogen mixtures - used for cutting aluminum and corrosion-resistant steel.
Other factors that contribute to the obtained cutting result are: the current intensity, which affects the temperature and strength of the plasma arc, the plasma arc voltage, which determines the correct course of the machining process, the diameter of the nozzle responsible for narrowing the plasma arc, the location of the torch in relation to the material, type, pressure and gas intensity as well as the type and structure of the electrode.
What is plasma cutting - technology characteristics
Plasma cutting involves melting and ejecting material from the gap with a highly concentrated plasma arc. It allows you to cut all materials that conduct electricity well. Due to the development and continuous improvement of this technology, both the range of cut materials and their thickness, as well as the cutting speed, have increased significantly. For example, the difference in the burning rate of plasma and oxygen is so great that, at a thickness of 3 mm, the plasma can replace 5 oxygen burners. With a thickness of 10 mm, this difference decreases to 2-3 times. Development of technology has also made plasma cutting competitive under certain conditions for such processes as e.g. laser cutting. It is possible with the use of High Definition plasma. Cutting takes place in a shield of swirling gases that narrow the plasma arc. The beam is more focused so that the edges of the detail being cut are less bevelled. In addition, less slag is created during the cutting process and parts are cut faster and more accurately. In addition, use liquid-cooled burners are used in HD technology, which ensures a longer service life of fast-wearing parts.
Advantages of plasma cutting:
- high cutting speed
- wide range of cutting thickness
- very narrow heat-affected zone
- cutting without preheating
- the smallest cutting gap
- low cost of investment
- possibility of cutting thin materials without overburning
- very good quality of the cut surface after the machining process
Plasma cutting machines in action. What materials can be cut with plasma?
Plasma arc, which is responsible for plasma cutting, is used to process electrically conductive materials (e.g. black and stainless steel and aluminum). Plasma cutting can be manual or mechanized. Plasma systems are prepared for cutting metal sheets up to 75 mm thick (manual systems) and up to 100 mm thick in the case of mechanized systems. Plasma cutting machines are used not only for cutting, but also for marking. Discover the types of our plasma cutting machines!