So my 5 Pro hasn’t even shipped yet and I am already thinking of ways to improve it. I am going to be cutting up a lot of thinner sheet goods on the machine and a vacuum hold down system would make doing so much easier. This got me thinking if there would be a way to make one that would be compatible with the hybrid table on the 5 Pro. Specifically make a series of MDF slates for the 5 pro that incorporate a vacuum system into them.
Basically I was thinking of making 4.5’ long versions of the slates that were made up of two pieces of 3/8" MDF glued together. In between would be channels for the vacuum to pull air out of. The top would have hundreds of small holes to evenly spread the vacuum out. The inside channels would be sealed with paint or something to keep the vacuum from leeching through the MDF. The part that stuck off the end would have a 1.5" hole on the top side. The holes would then be plumbed together using 1.5" PVC fittings and the shop vac hose would be attached to that. Might even put ball valves on each slat so each slat would be a zone.
Basically the two halves of the slats would look like this:
If you seal the sides it might work well. If not, you will lose too much suction with all that extra surface area. I would also not glue the pieces together in case you need to replace the top of one. Accidents happen.
Yeah I will probably seal the sides and bottom too. As for not gluing I would be worried about not making a good enough seal where the two parts meet. Plus I am more worried about accidently hitting a fastener than having to replace both parts. MDF and my time are cheap. Endmills and flying metal not so much.
I don’t have a lot to add other than this being one of the ideas/options we had in mind when we came up with the Hybrid Table. I’m eager to see how it’ll work.
You could use something similar. Just put a threaded insert into the bottom part.
A good vacuum will pull the top part of the MDF down to the bottom plate well enough to create its own seal. The fasteners are just there to prevent it from sliding around when the vacuum isn’t on.
Was also thinking a vacuum table would be great…was thinking of ordering a few extra aluminum slats and cutting 2" holes in them for piping. More of a traditional vac table, and could bolt the grid/MDF board using the original MDF slat spacing. Thoughts? Probably 2 zones for my 4x4 table (4x2 per zone)…I had good luck using the lighthouse motors with my shopbot and they are fairly affordable.
So now that I have the S5 Pro and am looking at clearances and the like, having the vacuum attachment port coming out the top would work IF you do not have the Sweepy Pro which I do. I am trying to think of a solution that does not involve drilling holes down through my table. I am wondering if something like 1/2" PEX pipe run from each slat to a manifold of some kind would provide enough vacuum.
I think that would work depending on what kind of vacuum system you are trying to do. It would work great for the gasket-no-leak-at-all type but I think that isn’t enough volume to do the traditional vacuum-through-MDF/LDF style. After making a few of these I have determined that you get better performance if you don’t go lower than about a 1.5" inside diameter pipe per 2 sq ft. You could still get it to work with 1/2" PEX but I think you would have a harder time getting a good vacuum. Each of those slats at 54" is 1.5 sq ft. I wouldn’t go any lower than 1" and I would personally just do 1.5" to be safe.
EDIT: The total diameter becomes less important the farther down the manifold. You don’t need to have enormous pipe once each slat converges into one. It does not need to be 1.5" x #-of-slats, just larger like 2"-3". This is because you should not have lots of surface open to the air when using it. On our table we have zones we can close and we mask off areas that we can’t close but aren’t fully covering. The larger diameter just helps with maintaining vacuum at higher airflows when you start cutting through your work piece.
If you already know this stuff just ignore me. I figure it could still be useful for people who look at it later.
My current plan is to make each slat have its own valve. I was planning on testing with 1/2" PVC pipe through a ball valve that would connect to a 1" manifold.
Do you mean holes in the top plate or bottom plate?
The top plate should be made from LDF preferably and have no holes. MDF can work as well if you can’t find LDF. Either material should be skim cut on both sides to remove the hard outer layer. If you then seal the edges with some sort of paint you will get better performance. The vacuum works through the MDF/LDF because it is so porous.
I would do 2 ports with a checkerboard pattern on the bottom plate per slat if you are using 1/2" pex. If you are making the bottom plate out of MDF as well, be sure to seal the whole thing with some sort of paint or spray. It will improve the vacuum significantly. You don’t want leaks from the bottom plate at all.
I am planning on using a shop vac. I only have access to MDF. The top I was planning on making look like an air hockey table. There are channels through the inside to those holes. I was kind of basing it off this video:
Some distributors call LDF other things like “lightweight MDF”. It isn’t super critical especially if you go with 1/2" thick MDF instead of 3/4" as the top plate.
I have generally avoided that style because they lose a bunch more suction if you uncover a hole while cutting vs a plain MDF top. Typically you have to put another thin layer of permeable material (such as Datron’s vac card or this: Black Box Grip-Lock Mat - Black Box Vacuum) on top in order to prevent loss of vacuum. You also must cover any unused area every time. I know that style can work and have used it in the past, it just takes more thought and planning to use. The industry standard on large machines is to use a plain MDF/LDF top because of the ease of use and lower CFM requirements to get the same level of vacuum. I’ll never go back now that I do it this way. You can see my Avid based machine with the table I made here: Chasing zeros on a Shapeoko 3 - #26 by nwallace
The picture shows the table before I put the 5x10 piece of LDF down.
A large shop vac should work fine. One thing to keep in mind is that most shop vacs are cooled by the air they suck in. In a case like this there won’t be much air moving through which could shorten the life of the motor if it gets too warm. Just keep an eye on it and try not to run it for hours at a time.
A good quality shop vac can work fine if you are okay with the limitations. If you are going to be running it all day you need something like this:
This is about the cheapest option for a vacuum designed for this purpose that I have seen. Technically you could make something similar with a vacuum motor and your own enclosure but it would be hard to match all the features of the Black Box Storm for the same or lower price. Cooling the motors and a pressure relief valve would probably be the hardest parts. We use the Hurricane for our machine and it works great. They are noisy even with the sound deadening base they come with. Not a big deal for us since it is in a workshop. Not sure how loud the Storm is but I bet it is a little louder than a normal shop vac. They get a little warm and have vents for cooling that would need to be accounted for if you wanted to stick it in an enclosure. For reference, here are some vacuum motors on Grainger Industrial’s website:
