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Frederic Gagnon
01-06-2015, 1:04 PM
I am moving the shop in a bigger space next month and going to install a 2nd laser engraver. Both machines are 48x36" with 80 watt lasers. I am wondering how to set-up the fume extraction system properly so there is no leaking or "backdrafts" from one machine to the other. Here is a very "professional" sketch I made of the set-up I plan to use. Is it as simple as that ? I am not sure if I need to add shut-offs on each side.

Also, is it advised to combine the fume extraction from the laser with dust piping from belt sander and table saw? Any tips on combining both ?

thanks!

Gary Hair
01-06-2015, 1:19 PM
I wouldn't worry about combining them, although I'm sure someone will tell you it's a fire hazard. I would, however, put in gates so that you can select the laser you are working with. If you don't, then the air will flow from the path of least resistance and if you if you have the top open on one laser the other won't have any airflow.

Keith Bielat
01-06-2015, 2:00 PM
I agree with Gary, be sure to have some type of shut off gate, I have a guillotine gate setup for each laser. For your diagram, I would put it near the Y split is for best efficiency. I have 4 lasers set up on 2 different extractors, my best piece of advice is to make sure what you have can handle the volume you need extracted. When I got my newest machine I had to replace my extractor because it couldn't handle the volume even with the 2nd laser on that line only being a 12x24 table. Also, using as much of the rigid (non-flexible) duct work as possible will increase efficiency, at some point the flexible tubing is necessary at least to the rear of the lasers. I personally can't explain the math, but that is what I have been told by quite a few HVAC friends.

Gary Hair
01-06-2015, 2:13 PM
One more thing - move your blower outside or any minute leaks will exhaust the fumes into your work area. Mine is outside in a small enclosure protected from the weather.

Frederic Gagnon
01-07-2015, 12:35 PM
Thanks for the help guys.

Joe Hillmann
01-07-2015, 12:41 PM
Put in blast gates, that way you can control which laser has air flow and how much and in the winter you can close them to keep the warm air inside your building. Also putting the blower as close to the end of the run as possible will make leaks less of a problem, If you put the blower outside it is quiet and you don't have to worry about leaks but in cold weather it can freeze up.

My blower is on the roof and I have blast gates but some warm humid air leaks around the blast gates when I am not running it. When it get to about -20 F the humidity in the air starts to freeze in the two feet of pipe that is fully exposed to the outside and the blower causing it to build up. The first thing that happens is ice/frost will build up on the fins of the blower and freeze it to the casing of the blower and it won't start. Then I have to go up on the roof in -20 weather with a wooden block and a hammer and do some tapping to free it up. If we have a long streak of -20 weather (a week or more) then the ice/frost in the last two feet of my pipe before the blower starts to build up. Last year I had to pull it all apart and it turned out that the ice/frost had built up about two inches thick all around the inside of the pipe severely reducing the volume of air that could flow. It was simple enough to put a tarp over the entire blower and piping and put an electric heater under it to thaw everything out but that is a problem I never had when the blower was in the attic.

Joe Hillmann
01-07-2015, 12:55 PM
You also asked about combining it with sawdust extraction. I can't say if that is a good or bad idea but if you do it make sure the piping is grounded, either through using metal ducting or if you use plastic run a bare copper wire inside all the pipes that is properly grounded at all ends as well as anchored to the ducting itself every so often. Moving any type of dry media through plastic ducting can build up huge static charges. It would be a shame for the static to somehow hurt the laser.

The other issue that MAY be a concern is fine dry sawdust suspended in air can be explosive, If a tiny piece of burning char gets sucked out of the laser and into the airborne dust it could be dangerous.