That was the solution( What has changed - can't seem to cut through anymore? - #13 by saok ). Thread is marked Solved.
Did you clean the lenes? Q tip and alcohol.
Thanks for your reply. Yes Mike, I did clean the lens but when I filled the Air Assist the original nozzle with a hole of around 13mm was replaced with one with a hole of around 3mm. I did notice the the 3… hole had gone slightly obround - maybe the laser was catching the side a bit. I could see no reason what it needed such a small hole so I bored it out to about 8mm. That and the Max Power setting in the software made a huge difference. I think the Max Power setting was the real culprit. Luckily, the Air kit came with two identical nozzles so I might now try putting the 3mm nozzle back on to see if it works and/or helps the air assist but so far so good. In theory the smaller nozzle should give a faster dust clearing jet of air but with all the other air paths I doubt that going from 3mm to 8mm will make much difference, but then again, whoever designed the Air Assist system did use a 3mm hole for a reason. It did look like the original 3mm hole was providing some interference with the laser. Best regards & Merry Christmas!
Maybe it would be helpful to edit the subject and add the word (Solved) at the end of the title.
As you can see, people are posting without reading the thread and just repeating what’s already been done.
Air assist actually performs three functions. The two you stated plus extinguishing a fire which is a security function. 
no one should operate a laser without air assist
Had the power supply go in our 100w the other day. We got arcing inside of the unit, and it did this on a run:
Lightobject got us a power supply in a day (USPS Express) and now our engraving is too deep, nice issue to have really.
If you run a failing power supply too long, it can kill your tube. Same for the reverse, trying to drive a failing tube. Kinda like alternators and batteries… they get this pact to take eachother out.
another good reason to have a milliamp meter on your machine so you can see the electrical current flowing through your tube so you understand its health status.
BTW, arcing can kill a Laser Power Supply(LPS).
Good idea Doug though I do continue to learn a lot on this thread and on this forum (ORIGINAL PROBLEM SOLVED).
Thanks Paul for the info. I wish AirAssist would have a bit more data regarding flow rates. How much is enough and how much air would just fan the flames? Is the 3mm nozzle hole size the optimum? (ORIGINAL PROBLEM RESOLVED).
Hello Peter, that’s a good question. I actually use a shop compressor, with an air valve. So I go with experience with the whistling sound. For engraving, I use very low pressure so that soot doesn’t blow all over my boards. It is a minimum so that the fumes don’t get on my lens. Usually flame is not a problem (depends on the material too). For cutting, it is a problem, especially when the beam gets through the material, You see often the flames starting on the under side. I like to give good pressure in this case. A trick if you have adjustable air pressure like I do, is to run engraving only first (using one layer), then I do the cutting only, with higher pressure. If you have good enough pressure you will see sparks flying of the cutting zone.
I went from my shop compressor(with regulator) to a 58W / 75L per minute aquarium pump for my K40 CO2 laser. The noise of the shop compressor was driving me nuts. My next addon will be a ball valve to cut in a really small aquarium pump when I turn off the 58W one. This would be for what you/Paul mentioned for engraving to just keep smoke out of the nozzle/lens. I do have a long small tube which directs a very small stream of air at the cut point. Big holes in a cone nozzle don’t give much power at the cut.
It was arcing after it had died.
[RDWorks Learning Lab 223 Air Assist Why, How and When - YouTube](https://Take a look at this for air assist help.)
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for years I tried to tell people about how their “air assist” nozzles were not doing much except helping keep their lens clean because the hole was too large and the nozzle was too far from the cut. When I saw Russ’s nozzle and head assembly I immediately appreciated how functional that cone/nozzle was at air assist because it had a tiny hole AND it was just millimeters from the work surface.
Great video.
The original - non air - nozzle was a whopping 13mm in diameter. The air assist replacement was 3mm but after a while it looked like the 3mm hole had gone a bit oval which I suspected was slightly interfering with the beam. I then bored the hole out to 8mm. Luckily, the air assist kit came with 2 nozzles so I have just fitted the 2nd - 3mm- unit and shall watch it to see if it to goes oval. The distance from the nozzle tip to the plane of the laser housing is 3mm which, with the 2mm fixed focus adjustment would put the nozzle around 5mm from the cut. I have also added a small fan blowing across the honeycomb table to aid in blowing the smoke away.
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Stick masking tape over the nozzle, fire a shot through it, and see where the hole appears relative to the opening.
If it’s not centered, then you know which way to adjust it for better results!
Thanks Ed = good idea! I learn something everyday on this forum. my thanks to all of you.
if the beam is somehow burning your nozzle output hole then the machine is not calibrated(mirrors adjusted) or the nozzle is not fitting on the lens(if diode laser). The laser beam must be perpendicular to the bed in both X and Y directions and the bed must be parallel to the frame(X and Y).
if your beam moves around in a circle or oval as you move around the bed then the machine is not configured correctly.
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