I added vacuum to my laser cutting honeycomb table as a hold down. It turned out to also work well as an air assist and kept my garage smoke free.
Jim – I posted this on the Avid and Opt Facebook groups as well – Here’s the laser table that I came up with piggybacking on your idea.
It’s about 24" x 36" x 4" tall and has two 2-1/2" dust ports wye’d to a 4" hose which will vent direct to outside via a 2hp Jet dust collector blower.
On the interior of the table, I’ve got three 1/8" x 3/4" aluminum bar cross members notched around the honeycomb frame so that it’s in direct contact with the bottom of the honeycomb in order to counteract the deflection from both the weight of the honeycomb and the vacuum. I laminated a sheet of aluminum to the interior bottom surface in the event that I ever add a laser with enough focal length to get there. If/when I add a higher than 15W laser to my setup, I may have to angle my laser head slightly to keep the laser from reflecting off of the aluminum and back into the lens. I cut 7/8" holes in each of the plexiglass windows and used a small bit of clear silicone in the corners to hold them in place.
Already saw it over there 
Very nice job. Looks a lot better than my rebuild job.
Thats nice honeycomb. So much more choice on Amazon than when I built mine. Is that aluminum or stainless steel?
I believe it’s galvanized steel. I fastened it in the casework with screws so it can easily be replaced if it takes a beating from the laser over time.
Good. Mine is aluminum. It stands up to the laser fine, but you have to be super careful not to drop or drag stuff across the top because its so thin it damages very easily.
So funny @ezambob I came up with similar (but smaller) version of what you did. I used 3D printed adapters for those hoses just like you did (are yours 3D printed?)
I ended up abandoning that idea in favor of this one:
This had some advantages for me… and for our users:
-It doesn’t rely on 3D printing
-It’s lower profile so you get some more Z clearance (probably more of an issue with our deployment mechanism than on your setup)
-You can build it with a 2x4 sheet of plywood
The idea is that you can fasten it down to your table and hang the dust port off of the end of the machine on either end. For smaller machines like 4x2s you can hang it off the back or the front and still be able to reach the entire honeycomb with the laser.
I have the 4" hose run into one of these fans:
I actually have the fan plugged into one of the relays in my control box so it fires up automatically when I start a job, and back off when I am done. I have the duct run outside my shop. It does a surprisingly good job at removing smoke.
Now that you all know we just launched a laser I am thinking of open-sourcing this design so that folks like yourself can make it. (You’re welcome to download and use this one if you want)
I really like that exhaust fan. The 15W laser will generate a lot of smoke if you are cutting. I use my dust collector, but that is very noisy. If you are just getting rid of smoke and not vacuuming down, this is a great solution.
This fan is nearly silent. The stepper motors make more noise. I am a big fan (ha) of this setup.
For a V2 I’d like to make one that is 24x48. I’m thinking that I might need a bigger (or second) fan for that though.
Hey Eric,
I needed to rebuild mine because it was too tall and I burned out the honeycomb with a new laser.
I liked your design a lot so I copied most of it. I added a sight window on the side so I can see if the laser is cutting through, added a stainless steel sheet on the bottom to keep from cutitng through the bottom and added some draft holes to the end opposite the vacuum hose connection. This thing is a lot more compact and lighter than my original one. Thanks for the design.
I also went to steel honeycomb this time. Its much more durable than the aluminum one and being able to use magnets on top is nice too. If you use a shop vac or dust collector you can use the vacuum as a hold down too (I just use some heavy paper to block off the rest of the honeycomb), but I would recommend emptying your dust bin or bag first just in case there are any embers (thats rare, but possible).
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Really nice design, Jim! Does this work well when engraving too? Smoke extraction is definitely an issue with open diode lasers.
That is some excellent plagiarism @jjneeb ! I’m impressed!
Agreed, that’s exactly why I made this thing. So far it’s been fantastic for me. I’m lucky enough to have the thing vented to an outside wall. As long as I remember to turn it on the smoke is very minimal.
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Yes. For engraving, just don’t block off the sides of the honeycomb with paper and it will get most of the smoke from the sides. The air assist tends to blow the smoke a little sideways to help as well. If you don’t want to hold down and just are trying to get rid of smoke, then the duct fan Eric shows up above is probably best because its very quite, compact, and low power compared to a big dust collector. Venting to the outside keeps it nice and clear inside the garage (the downside is I’m pumping my airconditioning outside 
)
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Jim, What’s the hardware that you used as the center supports for the honeycomb and how did you attach it to the stainless steel base?
Hi Bob,
Those are elevator bolts (they are the ones with the very big, flat heads), with threaded rod couplers so I can adjust the height easily. I just attached them with good old JB weld to the SS bottom sheet.
I have been doing a large batch of Christmas tree ornaments and got tired of the constand noise of the dust collector, so I ordered one of these fans just in time to use it on the last 150 ornaments.
It obviously does’t have the static pressure of a large DC, but it pulls the loosest ornaments down flat enough to the honeycomb, and gets rid of all the smoke. Best of all, it is virtually silent compared to the fan on the laser.
I’ve been really impressed with that fan. Have you seen the dust shroud someone designed and posted here?
I printed one myself and it’s great.
Ya, that shroud is nice, especially if you mostly do engraving and little cutting.