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View Full Version : How much air assist pressure?



Thomas Hempleman
02-25-2006, 2:07 AM
In previous posts, I have seen references to specific air pressures for air assist on various materials. My LaserPro has a simple thumb screw valve adjustment to regulate pressure. Is there a way to tell what the actual pressure is other than just listening to the hiss? So far, I know that a quiet hiss is "a little bit of air" and a loud hiss is "a whole bunch of air" and anything in between is "anybody's guess". :confused: Not very precise!

Tom

Rodne Gold
02-25-2006, 5:23 AM
The ideal air pressure is just a little more than needed to stop flaming when cuting stuff like plastics etc. Too much promotes too much cooling of the cut surfaces leading to non polished edge and striation marks at the cut esge and can blow melt all over, too little allows cut edges to remelt or allows too much heat into the material.(works for engraving too with materials that are heat sensitive , air assist cools and actually allows far less heat affected zones where the laser pulses , generally leading to more definition and crisper engraving)
The air assist does a lot of stuff , it cools , it can promote a reaction , it ejects melt or "swarf" , stops flaming , blows away dirt at the point of lasering as well as actually "pinning" the substrate down at the point of lasering (thin stuff) and can have inert gas feeds to stop charring.
So its pretty important to get it right in terms of pressure or flow and positioning if you are able to direct the jet. Trial and error is generally what you have to do in the abscence of a proper regulator , or add a regulator with a gauge. the mercury's air assist goes thru the lens/mirror box at the head so you have to be very careful the air has NO oil or moisture as it can get onto the lenses and mirrors and the lens can burn. The Explorers air assist is better imho as it can be directed and doesnt flow over mirror or lens.

Joe Pelonio
02-25-2006, 10:48 AM
A decent regulator with gauge is less than $20 and easy to add into your
line between the compressor and laser, along with a water filter. When you adjust it to the pressure you want you will notice a drop when the laser is cutting, because of the size of the nozzle opening. So, you should make the adjustment while cutting. When it stops note the pressure at the gauge and write it down for future reference, or mark it. For example
you may find that set at 30lbs results in 24 lbs when cutting, which for me is good for most materials, but I have an alternate higher setting for 1/4" wood.