Adjust air assist

[john banks]

I'm new to air compressors. What methods do you guys use to adjust the air assist?

Restriction valve in line? (how kindly do electric compressors take to obstruction - ie high pressure but low flow?)
Electrical adjustment on or before the compressor? (how kindly do electric compressors take to working at lower voltage?)

Is there ever a reason to turn down the exhaust fan? Is it possible if you have little air assist but a powerful exhaust that you'd make a vacuum inside the machine and is that likely to be a benefit or hindrance from the point of view of hold down, combustion, how clean the cut is on various materials?

[Lee DeRaud]

I'm new to air compressors. What methods do you guys use to adjust the air assist?

Restriction valve in line? (how kindly do electric compressors take to obstruction - ie high pressure but low flow?)
I've never seen a compressor that didn't have some sort of pressure regulator already installed. And except for very-low-output devices like airbrush compressors, they all work quite well at high-pressure-low-flow: that's their normal mode, as the compressor cycles on and off as needed to keep a reservoir tank filled to high pressure...the working-pressure output just feeds from that through the regulator.

[Dee Gallo]

I like to keep a pressure gauge attached at all times. Even if you have a built in regulator, it's good to know exactly what the pressure is especially if you plan to use the compressor for different things such as laser air assist and airbrush for Cermark. I only use 10 pps for the laser but 40 for Cermark. I don't actually use the same compressor for both, since I use a CO2 tank for airbrushing (clean dry air), but you could. My tank has both a regulator and a gauge on it. My mini-compressor for the laser has an added moisture trap too.

~ dee

[Lee DeRaud]

I like to keep a pressure gauge attached at all times. Even if you have a built in regulator, it's good to know exactly what the pressure is especially if you plan to use the compressor for different things such as laser air assist and airbrush for Cermark. I only use 10 pps for the laser but 40 for Cermark. I don't actually use the same compressor for both, since I use a CO2 tank for airbrushing (clean dry air), but you could. My tank has both a regulator and a gauge on it. My mini-compressor for the laser has an added moisture trap too.I guess I always think of the regulator and guage as a package deal: the regulators I'm used to have a fitting for it, so if there's no guage, you'd have to plug the hole anyway.

The moisture trap is a good point: laser optics really don't like getting fogged up. I'm in a dry enough climate that I never see anything in the trap, but it can't hurt.

[john banks]

Initially I have a 15 CFM 6.5 PSI 0.7HP piston type compressor that is oil free, it is OK with 100% duty but has no reservoir/tank, and no regulator or gauge that I can see but I can easily fit one to the line. Also a smaller unit that will come with the machine. I do live in a humid climate though.

Noise level is important, and this one is OK. I realise it might not be up to the job and I might need something bigger, but this was economical and seems to have similar numbers to bigger and more expensive "silent" type units. If you run two compressors and T their outlets, do you need non-return or check valves to stop them fighting each other? It may be that I can just run extra air assist lines to the laser head as I believe my machine will have air going into the lens head and some modify it to also go into the kerf. So I could avoid joining them together if I setup like this.

Some of this I'll just have to play with when I get it, but I really appreciate the great input from you guys ahead of time so I can be prepared.

How important is pressure vs flow for general laser engraving and cutting?