[WoodMizer]

I was wondering if anyone could offer some advice on a vacuum pump?

I have a CAMWOOD 408 (4X8 table, 6hp water cooled spindle etc.) and it came with a Travaini 7.5Kw vacuum pump (model EVO1OM).

My question is this: Is this pump strong enough to hold down a piece of MDF (used as spoil board) as well as a piece of plywood on top of the MDF?

I had the pump running the other day (finally got around to wiring it into the circuit breaker) and it just doesn't seem to produce enough suction. I have a rapid speed of 60"/m at the moment and if the clamp is not really locked down the wood will shift when the tool is going around a corner. I'm thinking it really would need more suction to hold down a 3/4" piece of plywood with a 3/8" tool at this speed.

I phoned EX Factory and they told me that this pump was a bit of an after thought and may not work for this setup.

Any one have any ideas?

[MCPservice]

In most applications that I have ran across for your size table, 20hp positive displacement pumps are usually the smallest that I have seen used. There are a couple of things you could do with your setup.

1. Does your table use grids cut into the table and if so are you using some kind of table to seal the surface of the table to the spoil board, try to capture as much of the vacuum pressure as possible. You can also paint the edge of your MDF to keep the vacuum for being lost around the side.

2. If you are not using all of the table, you need to cover the area of the table that is open, cardboard, plastic, something to not allow lost of vacuum.

3. If cost allows, you can buy a stronger pump or a second pump and split your sides and allow each side to run on it's own pump.

Hope these ideas help.

[ger21]

Did you seal the edges of the MDF?

Do you have a really good seal on the bottom of the MDF, so that you can't hear any leaks?

These two are important.

But perhaps the most important is that plywood can be extremely difficult to hold, unless it is 100% perfectly flat. The reason is that most plywood today warps very quickly, and if one corner starts to warp upward, it's very easy to lose vacuum. If you can see any gaps around the edge when sucked down, it probably won't hold.

We use two 25HP pumps on a 5x12 table, and plywood still gives me trouble.
One thing I do is cut all the parts on a sheet leaving about .1", then go back and cut the last .1". That gives me the best results.

I have no experience with your specific pump, so can't tell you for sure if it would work. Do you know the CFM and in/mercury it can pull?