by Cre8ivdsgn » Fri Apr 05, 2013 2:42 pm
The cold fin portion might look heavy, but I bet its pretty light. Plus with the main platform made from a tiny piece of 0.125" 6061 al, I bet its not bad.
As far as separation goes, those magnets can be brutally strong, and having six points to distribute the forces through... well, just looking at the video I'm going to take a WAG and say the magnetic forces are at least an order of magnitude greater than the forces that could be generated by the NEMA 17 or even NEMA 23 motors. He'd have to smack the head against something to run the risk of separation.
My only gripe with the design is that the ball and socket joint need to be kept pristine. Those ball magnets - if they are rare earth - are composed of a powdered metal in binder, but then chrome plated. Its possible for the chrome plating to delaminate. And whether the surface is chrome or simple steel, debris will inevitably cause wear. It would be cool to have either the ball or screw have a wear surface of Rulon or something like, but it would have to be thin considering how rapidly the magnetic field strength drops off.
Andbody got any spare, artificial knee joints laying around?
Berry's joint strikes me as original and his idea of magnetic mounts is nifty. I like all the work he did with the 1/8" plate too - making the carriages and the main platform with that material.
Just a thought - in a past life I would shrink a small hole by setting a 1/2" steel ball over the hole and smacking the ball with a hammer. I did this to make a very fine laser aperature. But what I recall is that you could get a good sized dimple. What if he drilled a larger hole, smacked a ball to form th edges of the hole, and then epoxied the ball from the back end? Hmmm... I know I'm not that good with a hammer, but maybe with an arbor press?