What size air compressor do I need for my air plasma cutter?

All plasma manufacturers include minimum air flow and pressure requirements for an air compressor in the owner’s manual. These requirements differ between systems, but as an example, an air compressor for a plasma cutter like the Hypertherm Powermax45® requires 6 cubic feet per minute (cfm) at 90 psi.

It is important to keep in mind that these are MINIMUM requirements. If you plan to use your plasma cutter for hobby projects or for cutting an occasional piece of steel, then an air compressor for your plasma cutter with a cfm rating slightly higher than the minimum requirement listed in your owner's manual will likely be adequate. But if you do a lot of cutting, or plan to cut thick plate, we recommend using a compressor that is 1.5 to 2 times the plasma system requirement.

Beyond choosing the right size air compressor for your plasma cutter, it is critical that you ensure the air that reaches your plasma cutter is high quality air. Without it, your parts will not look good and your consumables will not last long.

Unfortunately, when thinking about air quality, people only focus on the plasma cutter air compressor and do not consider what happens to the air after it leaves the compressor. That’s an issue because as the air travels from the compressor to the tool it is intended for, it will often absorb condensation from the air line. If you are powering more than one tool from a single line, you can also have a situation where oil will back-feed into the line, passing the contaminant downstream. By the time the air reaches the Powermax®, it is no longer clean and dry.

To prevent this moist and dirty air from getting into your system, it is important to filter it twice – once at the compressor and a second time at the Powermax gas inlet. And though it is an extra expense, this second filter will save you hundreds, if not thousands, of dollars, by extending the life of your consumables, torch, and power supply. In addition, it will improve your cut quality saving you time on secondary operations.