Understanding air pressure and air flow in plasma cutting

Why low air pressure is a problem for plasma cutting

A very common problem with plasma cutting systems is low air pressure and/or insufficient air flow. This is particularly common with air plasma systems, relying on air supplied from a compressor as their plasma gas. Often, shop owners believe they need a larger compressor when experiencing air related issues, but that may not be the cause. Having a compressor capable of supplying the PSI and flow rate (scfh) required by the plasma manufacturer is needed, but it is not the only factor to consider.

Difference between PSI and Flow Rate

It is important to understand the difference between PSI and Flow Rate. You may have the pressure set correctly at the compressor, but that does not guarantee you are getting the required flow rate at the plasma power supply air inlet. Common causes for low flow rates include insufficient air hose diameter, to many or contaminated air filters, or debris in air line. It is recommended to place a pressure regulator directly up stream of the plasma air inlet. You may also consider adding an inline flow meter for greater visibility.

Where to find PSI and flow rate information for your plasma

Quality plasma systems like the Hypertherm Powermax units found on the MaverickCNC cutting machines will include information for both PSI as well as hot and cold flow rates requirements. Cold rate is measured with the air flowing through the plasma torch, but no arc being fired. Hot flow rate is measured while the torch is actually cutting. For example, the recommended setting for a Powermax 85 cutting ¼” steel at 85 amps is 90 PSI, 500 scfh cold flow , and 400 scfh hot flow.

Get more from your system by making sure to have proper air supply

Improper air supply may cause several issues including, but not limited to system errors, hard starting, poor cut quality, and reduced consumable life. Understanding your systems air requirements and adjusting them correctly will help you avoid these issues, allowing you to get the most out of your system.

Contact the MaverickCNC Sales Team for additional assistance:  888-988-7224

Jim Colt - Tips & Tricks

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