Hello everyone.

does any one know if the stainless steel polished (shapeways)
is suitable for masters.

and are they really POLISHED? or what.



thanks,
-Clay

The parts are 'polished' in the sense that the burrs and sharp edges are rubbed smooth. They're probably barrel-finished.

Polishing makes the pieces pleasant to touch, but it doesn't fix the inherent graininess of the stainless-steel modeling process. As the picture shows, exterior surfaces are more polished than interior ones. The grain is more pronounced than FDM or SLS, so I'd consider it less suitable for making molds.

Click the picture for a closer look.

how thin are those rings? On shapeways they say the min-thickness should be 3mm, but that looks quite a bit thinner...

How well does that ring work in metal? I have it in nylon, and it sort of works, but the material is weak enough that it's very easy to cheat.

The band varies from 0.60 mm at the edges to 1.4 mm at the middle.

I suspect Shapeways listed the wrong dimensions for the stainless steel. The manufacturing process is very similar to SLS polyamide, but with the added steps of infiltration with bronze (to make it solid) followed by polishing (to make it smooth).


The stainless steel ring is much more rigid than the polyamid ring so it's less vulnerable to 'cheating.' But stainless steel is manufactured in multiple steps, described above, yielding unpredictable tolerances that make the ring tighter in some places and looser in others.

A drawback of metal is that it's non-elastic. Someone did try to cheat on my stainless ring, slightly deforming one of the pieces. But I think they must have applied an unwise amount of force, since the pieces certainly don't bend easily.

I don't get it, those rings are a puzzle?

Yes, they were previously mentioned here.

The goal is to nest all 3 pieces together into a single 'engagement' ring, like the fully-assembled white ring shown at the link. The solid metal band is so big in the middle that the two outer rings won't slip over it, so the challenge is to figure out how to put them together. As Bram pointed out, the plastic version is flexible so people can 'cheat' by forcing the outer pieces to snap over the middle band.