Vacuum Pods vacuum requirement

For the type of work I do a typical spoil board vacuum system does not make sense for a number of reasons. I recently learned about vacuum pods and am looking at trying to use them for some of our work instead of our current method of screwing jobs to a board from the bottom and then bolting the board down.

A typical job is solid laminated lumber planed on the side that is going down and our new machine will have a flat aluminum table with threaded inserts so we should get a pretty good seal. I am looking at sonething like this Vacuumpods.com "Buy a Better Pod for Less..." or this Flat Plate One Piece Vacuum Pod

If I were running 8-12 of these how many CFM/HP would I need? I would hope not that many as I am assuming the leakage is minimal compared to a spoil board system. My cycle times are hours long and I sometimes leave the machine running over night on finishing toolpaths so I would want as small a pump as possible. However I definitely don't want any movement of the part. I see on the NEMI site they have spikes available which is something I would definitely try.

When I had a point to point machine that had pods it had a pretty small pump compared to the 10 hp on the router at that time. I never did know the exact size of it as it didn't have it on the tag. I do not have a number for you to compare, I'd think that a 5 hp would be plenty if not overkill to use for pods. Do you already have a pump?

One thing I'd consider is when you run unattended what happens if you lose vacuum?

macgyver said:

When I had a point to point machine that had pods it had a pretty small pump compared to the 10 hp on the router at that time. I never did know the exact size of it as it didn't have it on the tag. I do not have a number for you to compare, I'd think that a 5 hp would be plenty if not overkill to use for pods. Do you already have a pump?

One thing I'd consider is when you run unattended what happens if you lose vacuum?

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Thanks I was hoping it would be 5hp or less. I emailed 2 of the Pod manufacturers with this question and have not had a reply. I might try phoning. I don't have a pump yet and would like to buy the right size.

As far as losing the vacuum that is one more thing to worry about. I try to avoid running lights out but I do occasionally, I ensure I double check all the toolpaths run simulation and set up a video camera that I can check from home. Hopefully a second router will help with fewer overnight runs. I will look into adding a shutdown if vacuum is lost. I don't think that will be a problem with an industrial controller which the new machine has.

It is a good possibility that the new machine will have an alarm/stop when vac drops below a certain point. Mine has an alarm and stops when air pressure drops below 80 psi, shouldn't be hard to do the same on vac.

You might pm scruffy on here, he has made some pods for lifting and he might have the parameters for how much vac is needed.

I ordered 8 full sized pods and 2 1/4 sized pods from vacuumpods.com They tell me a 3/4hp pump is plenty. The Pods should be here in about a week and half and I am going to pick up a used pump. Not a huge investment and if it is not quite enough I can get a second one or pick up a slightly bigger one.

For now I am going to use tubing to feed them and just make sure we tape it down to keep it away from cutters. If they work well long term I want to build some sort of plenum underneath and something similar to the Nemi holes with a seal on top and a series of dowel holes for positive location when I am flipping jobs over.

Very rough rule of thumb. 2" vacuum equals 1 psi of hold down, at sea level. My point to point drill/router has a 10 hp rotary vane pump and is good for the majority of materials that would normally go through that machine, melamine, veneered FC or MDF core parts, general cabinet parts. But it would alarm out with very large mdf parts of ply parts. Vacuum level too low and we would need to sometimes exclude vac pods or apply packing tape to the sheet bottom.
My big router has a 5x12 plenum table and has a 25 Hp vane pump and that size pump is on the low side for a table that size. Many users go much bigger but my needs allow me some easy work arounds. Be aware that these pumps throw off a lot of heat, some call them vac pump heating devices.
Vac pods can also be made more effective by applying peel and stick fine sandpaper to their face. I have done that on many production special vac chucks. Another option is spray contact cement applied to the part bottom. Not a wet coat but gun/can at a distance to apply a fine, dry almost, spider web of adhesive. LET IT DRY! Should not transfer to your hand at all. And nothing on the pod either. Even better if it gets machined off in a second op.

This is something I am looking into as well. I have some used pods and I guess the one clear limitation or parameter that can be determined just from examining them is the size of the tube ports and the volume of air that could be drawn down them? These pods are off a Biese Rover that was scrapped and are apparently made to be used with the inserted air gasketing. I only went with these as opposed to a full vacuum table without gasketing in the hope they would require a lot less vacuum pump capacity.