Plasma cutters cut conductive materials, namely metal, by sending air (or inert gas) at high speed through a plasma torch. It passes through an electrical arc and forces plasma through the tip of the torch, which cuts the metal. Because the arc can reach 25,000 °C, plasma cutters are one of the fastest ways of cutting metal. Still, how do you choose the right one? Much like a welder, the type of plasma cutter required depends on your work.
Plasma cutting machines can cut almost every metal, so the thickness and quantity of metal requiring cutting are the primary considerations. You’ll also need to select one based on the following:
Also, combination units exist: a plasma cutter, a stick, and a TIG welder. This option is ideal for the occasional job. As for portable units powered by generators, you must choose one that can cope with said generator’s fluctuating power.
Other features and variables you must account for when selecting a plasma cutter are covered in the following sections.
The output power determines what the unit can cut. For instance, 12 amps from a 120V machine can cut most 1/8-inch-thick metals. In contrast, higher-powered units with 60 amps of output from a high voltage 230V device can slice through most metals around 7/8 inches thick.
Inverter-based plasma cutters deliver high cutting output power but are also much lighter than standard cutting units with the same cutting ability.
Some plasma cutters have built-in air compressors, while others may require separate purchases. The required air pressure varies; a portable machine running at 20-30 amps may need 80 psi (5.5 bar), whereas a larger automated system on 130-800 amps might need 115 psi (8 bar) or more.
Plasma cutter speed is recorded in IPM (inches per minute), and the job dictates the speed you’ll need. However, some units can cut through 1/2 inch of metal in a minute; others may take five minutes if the cutting speed is slow.
“Duty cycle” refers to the time the unit can operate within 10 minutes before needing to cool off. Generally, a plasma cutter with a five-minute duty cycle can run for 5 minutes, after which it must cool down for another 5 minutes. A machine operating at a lower power may have a longer duty cycle, but very high operating temperatures might reduce it.
Shorter duty cycles are great for smaller tasks in a home workshop, perhaps creating small, regular cuts, whereas a longer cycle is better for making longer, deeper cuts on large metal pieces.
Two common types of plasma cutting torches exist. The high frequency starting system is the most popular, which creates a spark with a high voltage transformer, spark-gap assembly, and capacitors. High frequency torches don’t have moving parts and are more reliable, although they need occasional maintenance and can interfere with other electric-powered machinery due to their electrical noise.
The second common type is the contact start torch; it uses a moving electrode or “nozzle” to ignite a spark and light the pilot arc. This torch switches on instantly without a pre-flow cycle and doesn’t interfere with electrical devices.
Consumables will be an ongoing cost – the electrodes and cutting tips, to be precise. It’s important to learn how fast your chosen cutter will use these up. Replacing damaged or worn-out electrodes and tips is essential in maintaining cutting speed and quality.
Our knowledgeable teams at Kerf Developments can help you select the ideal plasma cutter for your needs. If you need assistance or have a general inquiry, contact us today – we’re here to help.
