This video from Shopsabre shows some ABS getting cut. It’s being held down with a vacuum table.
At this part in the video:
you can see how they have created the fixture. What I can’t tell is where the vacuum is being pulled from. My guess is the spoil board is LDF or MDF and they are just using one zone of their vacuum system. The black gasket is creating the seal but I’m unsure what the inside channel is for. I’m also unsure how they are keeping the vacuum from seeping out all the other MDF surface area. Maybe the channel concentrates the pressure to that area?
Anyway I have a large order of ABS sheeting to mill and would like to replicate this but I can’t quite wrap my head around it. Thanks!
You are correct about the black gasket, and the fixture. the channel they have cut is to clean the surface of the MDF.
In this shot you can see the shine on the surface, that would pretty effectively block the air flow properties of the MDF.
So they have sliced off the surface of the MDF to get rid of that, or at least that is what i am seeing.
Maybe they have also put a seal coat on in which is what is making it shiny. That would explain the “wood grain” look to the top. It may be brush strokes.
Ok, So a full vac table under it and different spoil boards for each job.
Not really do-able for the hobbyist. Well for my wallet anyways.
I have been thinking about this fro my build. My base table is a MFT table with a grid of 20mm holes spaced 96mm x 96mm with a space about 300 high as a torsion box design that is all open.
So i was thinking of buying a vacuum cleaner motor (for like a ducted vac) and running that as the vacuum creator seeing i could put it a box that would be right under one of those holes, effectively giving me quite a lot of VAC pressure transferred to the top side of my table.
Now that I have that pressure on the tops side of my table I could easily create a set of MDF spoil boards that add up to the 18mm I have used for everything else. I fully intended to have separate spoil boards for storage purposes. The design for those I had in mind was using a 20mm disk glued to the underside in the same 96mmx 96mm pattern to hold it there and register it into the same location every time.
One of those sections could be a spoil board of say a 6mm MDF base layer sealed and has small channels cut into it as the Vac force spreader. Then a 18mm bit of MDF glued to the top of that 6mm bit (the bottom skimmed to release the surface to the vacuum)
Skim the surface of the table 18mm down a few mm to match the rest of the table abd you have a vac table.
Yeah, i know that is a lot to try and take in without pictures, check out my thread and you will start to see how i am going to bring it together.
I don’t understand the thought that you need so much vacuum you can do a full hold through the mdf. All it takes is a small shop vac and a bunch of 1/4 inch holes into the vacuum box. I did my 1st one this way and went to town with a full size router pushing as hard as I could, material never budged.
The mdf is just there to act as a replaceable spoilboard that is porous enough to pull vacuum through. If you didn’t have the mdf, you would be cutting through to the semi-permanent table top of the machine.
That’s a good point. My first vacuum table couldn’t have holes in it as I was using a drag knife with sheet vinyl. If you don’t drill holes into the board, it allows the table to be used for multiple different projects without worrying about covering holes that would release vacuum if left uncovered. I will consider your idea though on an upcoming production run where the work holding doesn’t change. Thanks for getting me to think outside of the box.
I like to be cheap when I can, cheaper to use a little vacuum than it is run my vacuum pump, so little holes wins :laugh: I tend to cut the same parts so a couple inches of painters tape over an extra hole takes care of the leaks.
