Not printable but conform to the design rules?

Hi,

I was very pleased when a custumer ordered one of my designs in Silver Glossy. It was the "Amour Fou Pendant" which was printed in stainless steel a couple of times before. The next day I've got a message from shapeways service that the design is "not printable" ...

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Amour Fou Pendant in Silver Glossy
Reason: Thin walls
Additional information: too fragile too handle
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It is always frustrating if a model gets rejected but in this case I find no violation against the design rules. The wall thickness is above 0.8 mm and the depth is even 3 mm. It looks fragile but it is in fact pretty stable.
I wrote to the always friendly service and got the answer that "the walls indeed are thicker than 0.8mm but it seems that this model is too fragile like this" and that this issue will be forwarded to the production facility. This was on thurstday and I got no further infos about that.

I'm really upset especially cause this was a customer order.
As far as I know 3d printing is not an automated process. Instead every design will be proved by the people in the production facility during the preparation of the printing process. OK, everyone makes mistakes sometimes. I think this means to admit that this can happen the guys in the production facility, too. Maybe I've missed something in the design rules. I'm looking forward to get some useful feeback from the service.
If it was in fact a mistake by the production facility, I like to see a prompt and customer-friendly solution here.

Does anyone else got an issue like that?

Cheers!
Michael

Long thread on the rejection issue: https://www.shapeways.com/forum/index.php?t=msg&th=12976& amp;start=0&

If it prints ok in stainless it MUST print in silver, imo.

Of course, with all the recent rejections maybe they won't print it in stainless now.

Hey Michael, please use the thread fx pointed to. I'm trying to consolidate the rejections into one thread, as I'm pointing the team to that thread to address the issues of rejections. So please feel free to share your story there.

Hey Michael,

ouch, I can understand your frustration. I was under the impression that printability in steel would ensure printability in silver as well, so I did some asking around. Here's the answer I got:

Also, but I'm not sure how useful this would be for you:

.

It doesn't solve your problem I'm afraid, but maybe it gives a little more insight..

Bart

Let me see if I can add any light to this. Rather than posting in the other thread, I'm keeping this answer here relevant to just THIS model.

Even though your model does fall within the design guidleines, I think your model has some issues with physical support. As Bart mentioned, the raw wax has a different strength component than the raw steel does.

Consider this picture:


The item in red at the back, if you pick it up by either one of the spheres, it is going to break at the little connecting tube, even if the tube is 2-3 times thicker than the "minimum wall thickness". It's a matter of pure physics.. the amount of mass on the other end is more than the tube in the middle can support. But, for the object at the front in blue/green, it is possible that it could survive with the tubes at the absolute minimum thickness.

I would expect that your string of characters would snap in the middle, because there's not enough physical structure connecting the ends to keep them from twisting thereby applying too much pressure on the center.

You might try making the structure more complicated.. add some decorative cross-supports in some places, a long bar across the whole back for support, or you may have to make the whole thing thicker. I don't know which would be more acceptable from an artistic design standpoint. that's a question you'll have to make. It could be that if you focus on making the center parts thicker, you might be able to leave the outer ends thinner.