Is there any control over the air assist?
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Not yet that I know of, but that’s ‘in the hopper’ I believe.
It’s in the head, generated by the cutest little fan you ever saw, 3/4"square frame.
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Maybe it would be possible to add a control valve in the tubing to the head, if the GF uses tubing to deliver air assist. I’m thinking of the way that Russ (the RDWorks Learning Lab) guy does it.
The air assist is actually a small radial blower attached underneath the bracket the head mounts on. The tiny fan inside the head is just to keep the lens clean.
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You’re right, it is under there - it’s the same type that’s in the head, just a bit bigger.
The one in the head is an axial fan looking at the pictures @marmak3261 provided. I think the one underneath is a radial blower. They generate more pressure.
From the photos, the one for the air assist looks like what’s sometimes called a server fan. Heftier, sometimes two stages, generates a much higher pressure differential than the regular fans. (I’ve used them to make little hovercraft.)
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There’s always duct tape 
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I stand corrected. I think a radial fan would be a better design choice blowing through a small duct like that.
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Or use the tried-and-true method of pushing the air through a tube. Take the weight off the head (so it can move faster), use a larger fan (quieter, more powerful, and/or more efficient), and use cleaner air.
I’m not saying my laser has the most bestest air assist in the world or anything, but it’s created by a glorified aquarium air pump and piped in through ~1/8" OD hose. Seems like this would be a prime place for Glowforge to emulate rather than reinvent.
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Yes normally diaphragm pumps are used to give a much higher pressure and more concentrated jet for air assist. I was surprised to find GlowForge used a fan mounted on the head. Seeing the small duct I assumed it must be a radial blower.
Axial fans don’t push air through small ducts very well. I showed that experimentally here: http://hydraraptor.blogspot.co.uk/2016/02/cool-maps.html
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Like many of the discussions, it’s all academic at this point. It works as is.
Real time video.
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From Russ’s YouTube videos and various import laser web sites it would seem that the most common method of providing air assist is from a diaphragm pump which blows air through a tube to inside the the laser nozzle somewhat below the lens. It looks like GF blows air across the bottom of the head instead. Maybe it makes no difference in actual but it seems like the former method would do a better job of keeping smoke, fumes, and debris away from the lens. Have any of the PRU folks had occasion to check for dirt or hazing on their lens? Assuming of course that they are allowed to do that.
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On the exposed part of my head lens there has never been any noticeable hazing or dirt. I wipe it and two other exposed windows in the beam path about once a week just for the heck of it. . Apparently the smoke path does a pretty good job of bypassing those windows. On the other hand much of everything else inside the enclosure is covered and in need of serious cleaning.
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I’ve had to clean the lens. There is a special removal tool that makes it easy.
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From watching Russ’ videos I think a downwards jet is best for deep cutting wood with less char and air across the top is best for engraving. With there being no space under the honey comb I can see why GF blows across and not down.
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There is a little more than an inch space below the grid.
Just curious. But if you didn’t want the air assist to blow up something really light like paper, couldn’t we just cover up the air assist? Or would that just be a bad idea and cause flare ups and fire?
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The potential for flares would prompt me to use some form of hold-down and keep the air.
Collected an assortment of the home Depot flooring samples, and wow! The finish on some of that burns like a volatile fuel. Air assist-good!
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