I have a vacuum chuck for my wood lathe. It's very handy for holding bowls when finishing their bottoms. It can also be used to turn spheres and other objects. In fact, it's about the only way to hold roundish objects at a single point without marring the object being turned. You can see how these work here: http://sawsndust.com/a-vacuumchuck.htm .

I'm thinking a vacuum chuck for the Egg-Bot would have its uses. When used to print spheres, for example, it would allow more of the surface to be printed, and would automatically centre the sphere on the chuck (relative to its turning axis). Very little vacuum would be needed. One could use an electric or hand vacuum pump, even a vacuum cleaner.

All vacuum chucks for lathes that I'm aware of require the spindle that goes through the headstock to be hollow. One could easily make something similar for the Egg-Bot by relocating the turning stepper and having it turn a hollow spindle to which the object-holder is attached. The connection could be with gears, chain & sprockets, or belt and pulleys. There's got to be a better way, though.

I'm fishing for ideas to add a vacuum chuck to the stepper's shaft, with a plastic tube (providing the suction) attached to the chuck between a pair of air-tight bearings (i.e, so the plastic tubing would not turn when the motor's shaft turns). I've poked around trying to find whether something like this already exists, but no luck so far.

Any suggestions would be appreciated.

Cary

How well would vacuum chucks work on irregular-surface objects such as golf balls, miniature pumpkins, etc?

That's my biggest hangup on the whole idea at this point. Also the increase in complexity for people to have a vacuum source at their disposal to be able to use the Eggbot, which could get rather noisy/annoying after a dozen or more eggs at Easter time or in a booth at a fair/expo.

Also, the limit on the available drawing area of the surface is mostly due to pen interference with the frame and stepper itself, and not necessarily with the stepper chuck and "vice" on the other end. I honestly don't see what adding a vacuum chuck would do that the more simple setup isn't already currently doing.

This sounds tricky to do in miniature, although it is surely possible. A better question is whether it would really be worth the effort. Yes, it would let you get slightly closer to the "bottom" of the egg, but so would just using a longer 1/4" rod for the plunger (along with an extra spring or some spacers). You'd also need to modify the pen arm hinge to use a spring-loaded feed, rather than gravity feed to get all the way to the bottom.

Quote by: squall_line

How well would vacuum chucks work on irregular-surface objects such as golf balls, miniature pumpkins, etc?

That's my biggest hangup on the whole idea at this point. Also the increase in complexity for people to have a vacuum source at their disposal to be able to use the Eggbot, which could get rather noisy/annoying after a dozen or more eggs at Easter time or in a booth at a fair/expo.

I'd think that with some compressible material, like rubber, on the face of the egg-holder, you'd be able to hold the items you mentioned, and there's no need for its operation to be noisy. The vacuum pump I use in my shop runs off compressed air and is very quiet. Yes, the compressor itself is noisy, but a bottle of compressed air probably would keep a vacuum chuck on the Egg-Bot going for days. Even small electric vacuum pumps are not especially noisy (and can be very quiet if enclosed).

I'm now questioning the utility of a vacuum chuck, but I do think it would work with a variety of roundish objects. Also, thinking more about options for printing spheres has put me on what I hope is a more productive track...

Cary