Question About The Malleability Ofbronze Infused Stainless Steel

I recently received my first failed print in stainless. (To be fair, I didn't get it through Shapeways.) The piece is intended to slide over a leather belt to provide an anchor point for a key ring. I'm sorry that the images are not really "show" quality, but they are at full resolution...



And this is a screenshot of what I designed with the "trouble" areas circled...


I'm pretty sure I know what happened. At some point in the process, it simply buckled under it's own weight.

Anyway, I have two questions.
1.) Can this material be heated enough to allow a shim or wedge of some kind to be forced through the piece in order to remove the distortion (save the piece) or will it behave like cast iron and simply crack ?
2.) If I add support pillars in the cavity, can this type of distortion be prevented?

Any input at all would be greatly appreciated.

If it's any consolation, you're not alone.

Here my pain from 2016:
https://www.shapeways.com/forum/t/its-a-banana-why.34988/#post-132774

Sorry it's taken me so long to reply...

I read your whole post and I agree. It's the same issue I have. However, you never said what you ended up doing. Did you fix it? Or throw it in a drawer someplace?

Unfortunately, at the moment I don't have photos, but I managed to straighten my print enough to make it work. I took a chance (because I couldn't find an answer) and took a small butane torch to the side that sagged most and heated it until I started to see a slight "rainbow" effect from the heat and then hammered a couple of flat washers through it. And I'll say this. This shit is HARD!
I worked as an auto mechanic for over 30 years and have a wide understanding of metals in general. This stuff is like cast iron. You can only bend it so far when it's cold, before it fractures and breaks. If you get it hot enough, but BEFORE the melting point of the bronze, you can probably get quite a bit of flex out of it. It might be interesting to see what could be done with a good old fashioned forge...

I'll post some pics as soon as I can...

I ordered a couple of test items from Shapeways in the black bronze finish, and have found it to have quite a bit of ductility - way more that I would have imagined. I had a few cuff bracelet prints made and they will definitely handle the kind of flexing that people apply to bracelets to adjust them to fit, although they better have a pretty firm grip to make it happen!

I think you should be able to just take a wooden wedge and hammer it into the opening to restore the shape. As to why it sagged, I think that the part has to be self supporting to a certain extent while it is in the green state before sintering.

This is my experience also, that it's like very work-hardened bronze and will break rather than bend. Much depends on the shape of the piece, obviously thinner and multiply-supported areas are bendier than thick slabs, but basically you want the print to be the shape it should be.

Long unsupported areas will warp, that's a thing. Pillars will help.

Thank you for the confirmation. I've added pillars to the design. I just haven't uploaded it yet. Working with SS as a prototype can be costly, so I have to wait until I can afford it. I can't prototype in any of the plastics because the material characteristics aren't the same. That and the fact I'm afraid of another failure (sigh).

Again. Thanks for the input...

Finely got some pics. Once again I'm sorry about the quality. I had a co-worker snap them. My hope is to make this customizable without effort on the customer side.

And once again, I'm gonna state that this shit is HARD!
The hole at the bottom was designed at 0.25" and due to a miscalculation on my part, I had to drill it out to 0.3125"
I used a standard electric drill and a cobalt bit. At varying speeds and working from both sides it took me almost 15 minutes to ream it out.

Anyway, I just want to thank y'all for the input...

Sorry it's taken so long to reply...

Judging from the effort I had to put into getting this print "workable" there is no way in hell a wood wedge would work. (can't believe I just said that)

If I had the money, I'd like to try some "destructive" testing of this stuff. Just about everything I've read here, says you really need to use carbide to work it cold. I'm wondering if anybody has tried to MELT it??
How does it behave when it gets to the melting point of the "binder"?
What happens when you go PAST that temperature?
Could it be hammered in a forge?

Just wondering...

I've never tried melting any. There isn't any nonmetallic binder in the final print, it's stainless grains that have beeen eutectically welded together, with bronze wicked in after printing to fill in the porosity. About 60% steel 40% bronze. I've heard it's possible to weld it, though to get a perfect color match you'd have to print the rod too.

I imagine, without evidence, that its mechanical feel comes from the micro-lattice of stainless particles, which seems like it would be more rigid and brittle than a continous metal. Melting would disrupt that structure. As printed, although it's two metals it isn't an alloy because they're never both molten at the same time. If you melted a bunch of it bodily I don't know what it would do -- maybe it would start to separate out because the iron wants to float on top of the bronze? Idk metallurgy is hard.

Anyway I have a lot of scrap and could donate some for testing if you promise to post what happens.

I wish I could take you up on that offer. Unfortunately, at the moment I don't have anything hotter than propane. However. I'll ask around and see if I can lay my hands on something hotter. If I can, I'm more than willing to get pics and videos posted...I'll let you know if I do...

Actually now I remember, I did one time try welding it with one of those jewelry pulse-arc welders, that can weld anything to anything provided it's tiny. It worked. I didn't pursue the project for other reasons, and I didn't spend time refining the settings or anything, but it was clear this machine can weld this material.