Thanks, I didn't notice the problem.
The site is hosted by Cadlink. It's a 1yr free bonus for buying signlab7. Although it is very easy to setup and upload pictures, the system stability and site uptime has been less than outstanding.
I constructed the vacuum table like an air hocky table, except I used 2 4x8 sheets of 3/4" MDF. I used the router to drill a hole every 6" in the table. These holes were plugged with automatic "ball valves" so there are no air leaks to reduce the vacuum. A grid pattern of adhesive weather stripping is used to isolate each "ball valve".
I can place a sign blank anywhere on the table and it is held in place automatically.
The best feature is that the design is so effecient that I use a Fein shopvac instead of a 5-10 hp blower.
hello Ernie, I hope I will not ask for too much... i'm looking to get one of this systems for my self from practicalcnc.... can you please post more detailed pictures on a vacuum hold down sysytem and pictures of it's main parts... valves... connection...etc. Also if you would a step-by-step instructions on how to do it.
Chris, when I need to cut through I use transfer tape on the bottom side this also helps to hold small parts in place. For lagre pieces I will use a piece of sacrifical material under the piece that I want to cut.
I use peg board as a layer under parts I cut all the way thru. The advantages of this approach are many:
1) it's cheap. 2) the holes transfer vacuum straight up to the part and minimize leakage to the sides. 3) the rough side really grabs the signfoam. 4) it can be cut to the general size of the sign to eliminate activation of unneeded ball valves. 5) it can be used many times before it's worn out.
I was thinking of writing an article on how to build a vacuum table but decided there was not much interest by sign makers.