laser Surveillance

[Tom Bull]

X10 dot com has amazing camera package deals. Never used them, so can't recommend, just know prices are cheap. I have seen their stuff and it looks OK, one person I have talked to said their system was great in their beauty shop.

[Keith Outten]

Keith,

If the entire bar is pressurized and you only get flaming on the far right-hand side, is the bar pressurized from the left-hand side? If so, I'm willing to bet your pressure on the right side is significantly lower than on the left.

Dan,

I believe the air supply is in fact connected to the left side of the bar.
Knowing that, I tried increasing the air pressure so more air would be available to the right end of the bar but it hasn't made any difference even at 60 psi.

Mike,

I have tried every combination of speed and power settings possible to stop the flaming on the Xenetech. The problem isn't just thick acrylic, it flames when I cut any type of thin engravers plastic as well but only on the right side on the table. This would seem to eliminate speed and power from the equation.

It just seems strange to me that I have never seen a flame on my Epilog Legend no matter what material I have cut or what thickness.

[Dan Hintz]

I believe the air supply is in fact connected to the left side of the bar. Knowing that, I tried increasing the air pressure so more air would be available to the right end of the bar but it hasn't made any difference even at 60 psi.

Can you block off the left half of the bar, forcing the air to exit only on the right side, maybe using tape? It's too coincidental that it's powered on the left and the right-hand side is the problem area.

Air knives (essentially what you have) are notorious for this exact problem, particularly the ones designed without this problem in mind. The cheapest air knife is a series of holes drilled into a tube, and it also shows the worst characteristics. There is no laminar airflow on this type and very little directionality.

[Mike Null]

Keith

I am fairly sure that has to do with the variance of the exhaust air flow from one side to the other. (just a guess)

Mine flames worse in the front cutting x axis; cutting to the back in the x axis the flame is about half and side to side it's minimal. I think this is caused by the direction of the air from the air assist nozzle in conjunction with the exhaust air flow.

[Rodne Gold]

IMO one should never have flaming , even cutting thick stuff if you got enough pressure and flow in respect of air assist.
In 10+ years with 3 models of laser currently running 6 , we have had flaming one time and that was when our main compressor broke and we used an inadequate one.

The exhaust system itself , whether working or not has never a factor in our setup , I could however forsee that perhaps a very strong one could concievably "fan the flames".

I have no idea of our air assist pressures or flow
however they are either concentric with the lens or a directed nozzle and they all "hiss angrily" and push out a lot of air. I use a big 3 phase compressor for all shop air . An added benefit is that the high flow ejects the melt from the kerf well , providing its not too high so that it doesnt overcool the edges and make em frosty.

Is it not possible to retrofit a small directable nozzle type air assist connected with aquarium tubing to a good source of air - it doesnt even have to be dry if you bypass the lens. If you loop the tubing right , you should have minimal drag on the head and at any rate , you cut at slow speed so enfoulment or stiffish tubing shouldnt be an issue.

Im sure something better in the assist has to solve the problem.

As an aside , cast needs a higher temp to start burning , it will burn with a crackly smoking flame , but wont drip molten flaming balls that silent burning extruded would.

[Marc Myer]

I just realized that my flaming problem is primarily with Rowmark metal finish acrylic. But given the info you've provided, I'll begin a tweaking process and see how it can be improved.
There may be air flow impedance in the system that reduces pressure at the workpiece. A pinch in a hose, a piece of debris or buildup of goop from the compressor? Time to dig deeper.

[Roy Brewer]

I've noticed the air nozzle on my Epilog is not aimed precisely at the focal point.
Is that intentional?

Marc,

The design of your (standard) Epilog air assist is to strike the surface barely(~1/8") in front of where the laser strikes the surface. This forces vapors toward the exhaust. It is very common to find that, sometime during the learning curve, the operator allowed the product to strike and bend the AA nozzle while focusing. One set screw (not easily seen) allows the nozzle to be properly redirected if it is not bent. If it is bent remove and with a couple pair of vise grips, reform to where it strikes at the above mentioned location. Do not try to reform the AA nozzle while its mounted to the X-Axis assembly.

[Bill Cunningham]

Roy; When you say 1/8" in 'front' of where the laser strikes the surface..
Which 'in front" do you mean? The laser can travel in four directions, but the air direction from the nozzle is fixed.. Or, do you mean 'in front' meaning towards the front of the machine and not in front of the beam/kerf direction.
Is there a tech sheet to explain the correct position?

[Roy Brewer]

Roy; When you say 1/8" in 'front' of where the laser strikes the surface.. Which 'in front" do you mean?

Bill,

Sorry for the confusion. The air assist should blow vapors from the front of the machine toward the "sucker"(back of machine)hitting the surface ~1/8" closer to the operator who is always religiously watching the laser do it's thing, JIC!