3D printed stainless bolster

pafka

pafka

Joined
Sep 12, 2007
Messages
320
Maybe you have seen my post in KITH with the keyhole bolster. I machined it on a manual mill but even before I started I had this thought that this would be a good application for a 3D printing technology. So I found a service that will do that for you (pretty convenient with immediate online quoting based on the 3D model) and ordered two sample pieces.
They just arrived today.
Overall I am quite impressed.
I can see some faint lines/artifacts of the manufacturing process, but nothing unexpected.
I ordered slightly oversized variant to account for shrinkage (which may have been too cautious) and allowance for further machining/sanding/finishing, especially at the mouth where the blade will be fitted. The dimensions are very good, within the tolerances specified for the technology/material (apparently it is at least +-0.2mm which was achieved). For example the thickness was 14 mm and it came to 13.9 mm.
I paid about 48 Euro for two pieces (+20 for shipping). I can not make it that cheap no way. But of course this is because it was made in PRC. Quotes from EU were prohibitively expensive. I do not mention the specific service as I do not want to promote one specific vendor, I mostly want to mention the technology - so that you have it in your toolbox if you don't already.

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Tom Lipton mentioned this technology in one of his videos, I have thinking about it since. You will not go wrong watching this.
 
3d printed stainless, does that mean they build up the part from small bits of stainless?
Is it as strong as normal solid stainless?
 
This specific part was made with SLM (selective laser melting) - they deposit a layer of steel powder (specifically 316L), then melt a shape that corresponds to a "slice" of the final product at that height, and repeat. The question about final mechanical properties seems to be complicated, in some ways some materials may be better than conventional ingots, in other ways they can be worse. I do not know enough to be able to give a good answer. My thinking is that for a bolster this should not be an issue.
 
I watched a video several years back where they 3D printed a 1911 minus the springs. They proceeded to fire it from a distance because even they weren't sure if the printed parts were strong enough. Not a hitch. I've been wondering ever since how far out we are from that being the normal.
 
Any idea of the porosity compared to cast or billet? It will be interesting to see how it finishes. Cool tech!
 
Metal 3D printing has been around a lot longer than most people realize. The IMTS show in 2016 had a lot of different companies present that made metal 3D printing machines. fitzo fitzo I am no expert but with my understanding of how the process works the porosity would be somewhere in between castings and most billet materials.

pafka pafka Do you know if those parts you had made are solid clear through or is there some kind of internal structure to cut down on material usage and print time? Most 3D plastic printing is that way. It is uncommon to print something solid and without any intentional internal air pockets.
 
They do not offer any kind of infill options for this technology and material - it is my understanding that these parts are solid all the way. For filament 3d printing the reduced infil makes sense as you leave air behind - for SLM you would still leave the unmelted powder in the voids, I think that makes that possibility less appealing. But I am only speculating.
I weighed the finished part - my scale says it weighs 69.9 grams. Autodesk Fusion says it should weigh 74.9 grams. I would think that is close enough to say that it's solid.
 
Ok that’s good to know, thank you. I was going to suggest checking the weight vs the theoretical weight if you were not sure. It must be solid clear through.
 
Printing is already here as a normal. EU prices are not high if one searches a bit. Density is based on resolution so cheaper services tend to lower it to make it faster.
BUT, they all have a rule that no weapons should be printed, or part of it. Knives are weapons, even kitchen knives. For this one to get here, probably no one noticed a lie in the description. EU services will not ban knife related stuff. Chins rejected my kitchen knife handle out of titanium.
IMO, it is the way to go. A lot could be designed and printed, that could not be affordably made. And the choice of metals and plastics are really good today.
And I'll add a recommendation for design software. Plasticity 3D. Not hard to learn, with great capabilities. Cheap also.
 
that's a really cool application for the technology!
are you planning on hardening these components?

I was thinking just now how it would be cool to print up some aluminum cooling fin inserts that would fit in behind my radial platen. Maybe some bolt on fins for my quench plate, too...so many cool things that could be made!
 
I've been designing and having knife sheaths 3D printed from reinforced Nylon for years here in Germany. Plus knife grips and all kinds of parts. Works great. Metal printing is a fantastic process and more and more parts that were machined are now being printed or at least printed and then only need finish machining.
 

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