[Steveb1307]

Hey Guys, I am about to help a friend with a 10hp on CNC route and and I am a little unsure of the Principles behind the technology. Is it right that with this style of system if you were to completely block everything off it would not work. He has set it up but has a problem holding his product down(Flexible PVC Sheet) He is attempting to totally seal the bed and I am thinking this is not correct....ANy help or advice gretly appreciated

[CaptainVee]

If you use a low volume vacuum pump it must be- and remain sealed.

If you use a high volume pump than breaking the seal may (!) not always be a problem.

[Steveb1307]

Thnks for the reply, It is a regenerative blower type system. As more product is laid on the table it appears to lose vacuum. Do these system need a certain amount of air to pass through them or is it better to try and form an absolute vacuum. Thanks

[CaptainVee]

Absolute vacuum is best.

And depending on the volume of air being pumped that can rely on the tiniest of gaps needing to be closed.

[Steveb1307]

Hi, this is not a vacuum pump though but a regenerative blower. Therefore as I understood I thought it neede a certain amount of air passing through it to be effective, is this correct???

[Phife]

Regenerative blowers typically MUST have a bypass valve to allow air to keep flowing through.. On the 17hp one at work there is a bypass valves installed and calibrated to open at 11"HG, this works well for us.

We do alot of thin sheet stock too and the problem with the hold down for us was not enough flow through the spoilboard to hold the thin material down at the edges.

You must tape down the edges, and better still, drill and slot your table top to allow more air to flow through.

Get a by pass valve for sure, you will kill the blower by not allowing air through. You want a seal at the table and you want some sort of relief valve close to the pump thats properly calibrated to open a few "HG before the max vacuum the pump can generate.