First.....if anyone wants a tour of Hypertherm in Hanover and Lebanon NH, simply contact me at
jim.colt@hypertherm.com. We are in 13 different buildings in Hanover and Lebanon (all pretty close) but the Powermax air plasma units are all designed, engineered built and shipped from one location, all by employee owners. In regards to compressor sizing for any plasma cutter.....all the cutter requires is that a certain pressure is supplied to the inlet. The Hypertherm 30, 30XP and 45 all need anywhere between 90 and 125 psi at the inlet. This means that the plasma will operate on any air compressor that can supply at least 90 psi. If the flow rating of your compressor is the same as that of the plasma...then the compressor will run pretty much 100% of the time. If the compressor has a lower cfm rating....the plasma will run until the air pressure drops below 90 psi.....then the plasma will shut off the arc to protect the torch and consumables...and you can resume cutting when the pressure rises past 90 psi again. (actual shutoff is between about 80-85 psi). I often use my Powermax45 on a small Porter Cable compressor (designed for nail guns) that only flows about 3.2 cfm. I can cut continuously for about 40 seconds......which is close to 20 feet of cut on galvanized roofing, perhaps about 1 foot of cut on 3/8" steel. Most metal art will consist of short cuts with off time in between, which allows the compressor to build pressure. So...unless you are cutting long cuts, or a lot of cutting on the thickest materials....you can often use a compressor with a lower rating with perfectly fine results. Now my shop compressor flows 21 cfm.....often my cnc plasma cutter is running, unattended, and I may be using other air operated tools at the same time. In comparison to the Cutmaster 42i.....no new technology there. Rather, it was Thermal Dynamics closing down production at a US plant, laying off many long term workers...then they started buying the 42i from a Chinese company. Jobs lost, revenue gained. No new technology...rather they buy the units from China and install their own torch (from Mexico). It's not a bad little unit, power wise it has similar cut speeds to the Powerma30XP, and a lot less power than the Powermax45. So, a tour is available for the Hypertherm plant, heck, I'll even show you the empty Thermal Dynamics plant which is only 8 miles away! Jim Colt