I kept it as simple as possible, because I have never built anything like this. If you would like to make a more professional like vacuum tray, you might consider to follow the descriptions of @evansd2 or @timjedwards. They have both posted detailed pictures of their designs.
So I connected the battery directly to the fans and I use the on / off switch of the battery, which means I have to pull the tray partly out to use the switch. It looks like this:
All parts are cut on a GF pro.
Cutting fabric is the main reason I bought my glowforge…looks like I’m going to have to start sourcing vacuum tray components!
Nice! Have you tested how long the fans will run on a charge?
Nice! This looks like something I might be able to do. Thanks for posting this.
Genius! Well Done! 
So far I used the battery for a maximum of 3 hours. After that there was still 25% power left.
I’m going to have to try one I love tiny pieces
THIS IS GENIUS
Jonathan
PS: My unit is new and as tempting as this mod sounds, i gotta ‘behave’ for a year and not mod my GF
There’s no modification to the Glowforge in any way. The vacuum tray just pops right in.
I was thinking a hole for power cable, using a magnetic dock, so when tray is inserted in, it connects to power connector – ya know HOLES!!! 
Why would you do that? It’s totally functional with zero mods, seems like your way would be much harder with no gain?
I mean it’s a fancy idea, and that would be interesting and cool on some level, but it seems like putting wifi on a hammer. 
Hmmmm WIFI on a hammer!!! you may be onto something there!!!
Worthless without an accelerometer embedded in the head.
I have known blacksmiths that won’t use hydraulic hammers as it is harder to be as precise about the hit. Perhaps with camera s and AI they could work much faster?
New part recommendation: fan model THA0412BN
This fan pulls far more vacuum than the other models in the series, 2.4 in H2O, compared to ~1.4 for the THA0412AD series.
https://www.digikey.com/en/products/detail/delta-electronics/THA0412BN/2745095
I know I am very late to the vacuum tray party but, I finally got around to making one. This project owes a lot to the previous examples here.
I did the design in Inkscape. I used one of the tabbed box generator extensions ( GitHub - paulh-rnd/TabbedBoxMaker: Inkscape tabbed box generator plugin - quickly design complex "finger jointed" boxes ) for the two main bodies: the tray and the fan box. I modified the output to break the pieces into sizes the Glowforge can cut and, to add additional features like holes for the fan and electronics and channels for air flow.
The tray is Thick Draftboard. I lined the bottom with aluminum foil for extra protection in case any stray lasering gets through. It’s probably overkill but, I sealed the seams with silicone caulk to reduce air leaks. The cutting surface is a piece of perforated stainless steel plate sandwiched in a layered Medium Draftboard frame. That is held down to the rest of the tray using magnets, with an EVA foam gasket to help with air leaks.
My original intent was to use the same mesh others were using. I couldn’t get it as flat as I wanted. So, I switched to the perforated steel plate.
The fan box is Medium Draftboard with press-fit holes for the power connector and switch. The fan is bolted on to the end opposite the switch. This uses a 12v fan and a standard 12v power supply. The cord hangs out through the front of the lid of the machine. The electronics are basically a summary of the recommended parts from this thread.
I painted all the MDF black so it would look more finished and less cobbled together.
Cutting the plate steel without access to a shear was a new adventure for me but, worked out really well.
The cutting surface is a little higher than the standard tray and, the air assist clears the fan box by a hair. If I were going to make another one, I am confident I could shave some height off both components. It works well. So, I probably won’t, unless I run into problems as I use it more.
Here is a 1.6-minute video of it in action:
Blog post with more photos: Vacuum Work Hold-Down Tray - Evermore Stud.io
Very snazzy looking! If you don’t cover the rest, does it not pull down at all, or just not enough?
Wow! Well executed. This will certainly by nice to have when you are cutting your fantastic pop up cards.
The more area that is covered, the stronger the hold-down. There is some with some of it uncovered but, there is a big increase with most of the surface covered.
Yeah I keep printer paper handy to lay down on the screen around my workpiece. Suction drops off quickly with open space.
