This week I started to move forward on setting up for a small sign thing for equestrians after making some prototypes that I like. Because these will be personalized, I needed a work holding setup that was accurate, quick and secure. Vacuum is excellent for this and that's the route I chose. I happen to have a nice Gast vacuum pump that I've owned for many years for lathe work. It's not appropriate for larger CNC tasks, but perfect for fixtures that hold smaller workpieces. So I relocated it from the lathe stand to under the CNC machine and then proceeded to create my fixture for these small signs.

I chose to use some Corian scraps for the fixture...no leakage, easy to cut and very durable. I created the design in VCarvePro, starting with the existing prototype sign profile to provide a recess that increases lateral hold and then milled an air chamber and gasket groove. The end result...

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Since I need provide for an air path from a connection to the vacuum pump, I setup for a double sided job using indexing pins so I could flip the workpiece and route a groove in the underside of the top layer to provide for that path. Note I stopped this groove shy of the edge so its essentially asymmetric nature wouldn't interfere with drilling a 1/2" hole in from the edge for the air connection.

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I then used Gorilla glue to laminate the machined piece to a second piece of Corian, using cauls to insure things stayed absolutely flat. Once that cured overnight, I cleaned up the edges and then drilled my 1/2" hole for the threaded air connection. Theoretically, I should have used a slightly smaller drill bit and then tapped the hole, but I'm not setup with tooling for that, so I decided that I'd get just enough bite from the threads cutting their own and then the epoxy would insure everything stayed tight and sealed. And that turned out to be accurate, especially since the nature of vacuum pulls the connector tighter, rather than the opposite as it would with compressed air.

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Interestingly, when I tested the holding power, even without a gasket installed (material arrives tomorrow), I could not pry the sign blank off the fixture even with a flat screwdriver.

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So this is setup job one ready to go. I have a few more things to work on before I start offering actual product, but I'm happy to be making progress. I'm setup with the local Corian distributor, too. I seem to be getting pretty comfortable with the toolpathing aspect of these simpler projects and get get through a design and set of cutting files pretty quickly at this point. Still "walking" before "running", but going in the right direction.