More questions on air assist.

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More questions on air assist.

Postby LeonS » Sat Jan 02, 2010 4:04 pm

I have a Chinese 40W laser that has no air assist and also suffers from an inadequate fume extraction system. Smoke tends to linger in the areas farthest from the fume extraction vent.

I have tried installing (temporarily) a couple of computer fans near the front of the machine to blow the smoke towards the exhaust vent. That helped by I suspect that pulling air from the outside of the machine and directing it across the cutting surface would be more effective.

I hope to add air assist to the laser via a cone around the lens with an external air compressor. I may need to start with just an air jet from a tube attached to the lens carrier.

If I do use a directed cone air assist, should I be as concerned about the inefficiencies of the fume extraction system?

Similarly, if I use the air assist tube option would the smoke inside the laser be more of an issue?

Thanks in advance,
Leon
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Re: More questions on air assist.

Postby bdring » Sat Jan 02, 2010 5:03 pm

The extraction blower is trying to pull the air out of the cabinet. It needs a fresh source to work efficiently. Any extra open intake area will help. I filtered my intake to prevent dust from entering the enclosure.

Some types of smoke are really bad to linger around. Wood smoke tends to stick to anything and would ruin a mirror. Some plastics have some nasty stuff like chlorine gas which can wreak havoc. I know not to cut PVC, but I saw some cool vinyl record laser cuttings on the Internet. When I tried it, it made some nasty smoke that corroded some metal.

The air assist is designed to keep the the smoke out of the cutting beam and away from the lens. You definitely want to make sure the air source is clean from dust, particles and especially smoke. I used a cheap water filter cartridge on my pump intake.

As long as the air comes from a clean source, the air assist should not be bothered by the extra smoke. The volume of air coming from my air assist is small compared to that of the extraction blower.
Bart
"If you didn't build it, you will never own it."
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Re: More questions on air assist.

Postby LeonS » Sat Jan 02, 2010 8:01 pm

I think I will drill some holes in the front of the engraver to allow air to enter from the front and flow over the cutting area to the exhaust port. I could add some air under pressure through those holes if more flow is desired.

I also need to re-plumb my exhaust vent with rigid PVC pipe all the way from the wall vent to the last foot before the laser. Currently, I have saggy flex tube with lots of ridges. That must be presenting lots of resistance to airflow. I may also have to add an auxiliary blower to suck air out of the pipe at the output vent. I have to go up 5 feet and then about 10 more feet to get the exhaust outside the house.

Thanks,
Leon
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Location: Herndon, VA


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