Need a vacuum table expert

[rslaback]

I have a 4x8 prt in my school district. I have always wanted to put a vac table on it but up to this point have not been able to make it happen.

I have mostly looked at the dual vac motor option that Brady came up with forever ago. However, recently I have gained access to a surplus Leybold WSU501 blower. http://www.pchemlabs.com/product.asp?pid=3966 for specs.

Knowing basically nothing about the actual air flow and pressure requirements of what is needed and what would be too much I have no idea if this blower would work for me or not. I just know it might have potential and I can get it for cheap.

I would appreciate any feedback that those of you who have designed systems could share with me.

P.S. The 3 Phase is not a problem.

[Brady Watson]

You don't want that pump for a couple reasons. First, this is a booster pump - meaning that in order for it to operate correctly, you need a pre-evacuated chamber or plenum before you can turn it on. You cannot use it from atmospheric pressure and then have it build vacuum up to it's max suction.

Second, It is only about 3hp. You'd need at the minimum about 5 total hp to do what you want, regardless of how many units - let's say Feins or Lighthouse motors etc - although you can do pretty well with just a couple of them because they are more efficient than the low RPM pump motors.

Max achievable suction on this is around 11 inches of mercury (if my conversion is correct), which you could achieve or get close to with a lighthouse motor. This pump requires maintenance and is really not the ideal solution to your application. Finally...this is a roots pump, which will HAMMER everyone's brain and telegraph vibration in a 250 foot radius.

If you are going spend that much, get a turn key solution from ShopBot, or roll with the Lighthouse motors. Gary Campbell did a really nice job taking what I introduced and made it all purdy. You can find info on that here (http://www.talkshopbot.com/forum/showthread.php?t=11813&highlight=black+vacuum).

When it comes to designing your system, you need to answer a few questions about the work you are going to be doing. If you are doing nothing but full or partial sheets, then a dedicated vacuum grid would be a good choice. Otherwise, if you like to clamp, screw and tape parts down from time to time & need versatility in the system, just bore a 2" hole in the middle of the table and cut a BradyVac plenum from a single sheet of Ultralight MDF. Flip it over and turn on your vac. Done. You can remove the plenum and get your spoilboard back again if you want to clamp something down or drive a screw into the table for parts non conducive to vac hold down.

-B

[rslaback]

Thanks for the reply Brady. I really appreciate it. I have a couple lighthouse motors I just haven't put them into use yet. I will have to check out that thread.

I doubt what I would have had to give for that blower (<$200) would make a dent in a turn key. :D