Imagine a device that can heat a precise spot on a piece of metal to nearly four times the surface of the sun in a fraction of a second. That result is achieved with a plasma cutter, which can reach temperatures of 40,0000 degrees while a worker stands safely a few feet away. The surface of the sun only reaches a comparatively chilly 10,000 degrees.
Plasma cutting is a method of metal fabrication that cuts through electrically conductive materials with an accelerated jet of hot plasma. This includes steel, stainless teel, aluminum, brass, and copper. This differs slightly from laser cutting, which uses a different type of cutting power. Laser cutting uses a narrow, but intense beam of light. Plasma cutters are able to create an entirely different state of matter.
A Fourth State of Matter
Think back to elementary school science. You were probably taught that there were three states of matter: solid, liquid, and gas. This is best exemplified in water. Water is a solid (ice) when it is cold, a liquid at room temperature, and a gas (steam) when heated. Plasma is a fourth state of matter, and it created simply by adding even more energy. Adding energy to ice melts it into a liquid. Adding energy to water vaporizes it into steam. If you add enough energy, steam can break into its component gases, become electrically conductive, and become a high energy ionized gas called plasma.
In plasma cutting this plasma transfers energy into a conductive material for cutting. A gas such as nitrogen, oxygen, argon, or even regular air is forced through a narrow nozzle. An electric current ionizes the gas and turns it into a plasma arc, which melts the metal and blows away the molten excess.
How a Plasma Cutter Works
A plasma cutter has three critical components:
Power Supply – The power source must be a constant DC current in the typical range of 240-400 VDC. This determines the speed and cut thickness capability. The main purpose is to provide the correct energy to maintain the arc after ionization.
Pilot Arc Starting Circuit – This is a high-frequency generator circuit that produces an AC voltage of 5,000-10,000 volts at roughly 2 MHz. This creates a high intensity pilot arc that ionizes the gas inside the torch.
Torch – This is the holder for the consumable nozzle and electrode. Additionally, it provides cooling for these parts and maintains the plasma arc.
Many plasma cutters are mechanized for precision and run on CNC software. As a result, these can be programed for individual parts or small runs. Many manufacturers rely on CAD/CAM nesting software for greater features and capabilities. These can control and automatically set up virtually every aspect of the plasma cutting operation. In the past decade plasma torch manufacturers have engineered new models with a smaller nozzle and a thinner plasma arc. This allows near-laser precision on plasma cut edges.
One of the biggest advantages of this type of cutting it that it provides an accurate cut with no metal chips and a cleaner edge. Also, thanks to CNC maching plasma cutting is used to cut diverse shapes. It is even used in three dimensions for things such as countersunk holes and chamfer edges.
For more information on how IMH Products can serve your plasma cutting needs please contact us at sales@imh.com.