Plasma Cutting: How Air Pressure Affects the Quality of the Cut

Have you ever wondered what the cut 50 plasma air requirements are ? If you are going to cut a steel plate that’s about 12 mm or half-inch thick and what would be the outcome? Well, as I thought, the air pressure needed for a plasma cutting machine to be able to cut such thick metal would be more or less, say 80 Psi or more. But to let us know what can be the effect of air pressure when cutting metals, I made this video and experiment using two levels of air pressure – 80 Psi and 50 Psi using the same plasma cutter.

I have used my new Flameweld pilot arc plasma cutter on this experiment because it is packed with 50 amps and it also has a Post-Time feature that allows me to choose the duration of air release through the torch to help in the cooling off of my consumables.

Now, the objective of this experiment is we are trying to find the right cut 50 plasma air requirements that would cut thick metals completely and avoid damaging or shortening the life of our consumables. As most of you may not know, the lower the plasma air pressure, the weaker the arc and the weaker the arc the more tendency the hot plasma could not cut through the metal but could even be blown back to the consumables which can damage them.

So what is the ideal air pressure needed for a plasma cutting machine?

I switched the Psi of my plasma cutter to 80 because this is the maximum capacity my compressor can handle and then switched my machine’s current to 50 amps. Then I switched my Post-Time button to three seconds and proceeded to cut the 12mm thick metal. The result was pretty good. The 80 Psi plasma air pressure is good enough to cut thick steel without bogging my machine down.

After this, I went on to switch the air pressure to 50 Psi but without changing any of my machine’s settings. Well, I thought that when I was cutting the steel, everything was going fine. But then I found out after reaching the end of the steel, the cut did not go through and the result was an ugly, incomplete cut that only melted the steel’s belly.

This proves that the Cut 50 plasma air requirements should go beyond the 50 Psi setting or better if 80 Psi or more. This will let you produce a more powerful and aggressive arc that could cut through thick steel. As you can see in this video, with 80 Psi, I even accidentally cut my metal table along with the metal plate I was cutting.