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Possibly somebody wrote and supplied a software package and equipment which makes them able to take a 3D scan of the patient's body and produce a model to print? Or qualified biomedical engineers and doctors spent numerous hours developing 3D-printable universal prostheses in conjunction with the company that produces the printers? That takes considerable technical know-how to pull off, and possibly a good bit of money that isn't included in your costing.

My daughter is a bio-mechanical engineer and works with prostheses in her paid job. Nights and weekends she works with this charity organization. Spanish doctors head the outfit. There's an Indian software engineer working in the Netherlands that has written most of the code. Basically, a doctor working in a 3rd world hell hole takes a few measurements of the amputee's arm or leg and emails them to the s/w engineer who runs it thru his custom coded preprocessor and the G-code for a properly sized prosthesis is generated and emailed back to Calcutta or wherever. If there is a problem with the printout my daughter runs it on her machine at home and fixes up any glitches. So, yes, lots of time and effort and skill went into developing the system but the end result is a desktop 3D printer on a desk somewhere in the third world printing out prostheses in a low tech environment for just a few dollars a pop.

This kind of support would probably not be available free of cost to a typical consumer or business in the 3D printer market.

Not yet, but I remember the days when an Epson dot matrix printer cost north of a thousand dollars and required a service/maintenance agreement. Now an ink cartridge costs more than the printer. What used to be called a photo-realistic printer is now a non-repairable commodity item. 3D printers will be heading down that same path. Looking at the cost curve and the feature growth of 3D printers over the last several years I see Moore's Law in full effect.

Add to this that you will not get the full mechanical strength out of the material.

I think you are only looking at the downside of a 3D printed part here. If the entire assembly is designed to use 3D printed parts from the get go a designer has a world of options only limited by his skill and imagination. Did you see my response to the gunsmith who thought springs could not be 3D printed? Take a look at that article. Those springs don't look anything like a typical coiled spring and they probably couldn't have been made without a 3D printer but they have features that are hard to duplicate with a traditionally manufactured spring. 3D Printed Spring Exceeds Traditional Manufacturing

I was talking to a Honda engineer a couple of days ago that was very excited about some of the part designs that he was getting approved that were simply not possible to be made on mills. Double and triple undercuts. Parts that are enclosed inside of a shell. Parts too delicate to support themselves until their structure is completed being printed with a supporting media that is evaporated away when the printout is done. He said, that for all of their technical expertise Honda, until recently, had been very reluctant to approve a design that could only be made on a 3D printer. But not any more. He was like a kid in a candy store talking about what he was going to be able to do now. I really don't think they would have to pay him to show up to work if they'd heard the excitement in his voice.

I'm not saying they're completely useless, but they're limited unless you have alot of time on your hands and access to other tools/equipment.

Have you ever been inside a MakerSpace facility? For about $200/month you have access to ALL of their equipment. Laser sintering, top of the line printers, the works. Sometimes I wish I was a kid again so I could go play.

"the end result is a desktop 3D printer on a desk somewhere in the third world printing out prostheses in a low tech environment for just a few dollars a pop."

That is cool. No doubt about it. Still a pretty narrow niche as far as the broader consumer/manufacturing market is concerned.

3D printers will be heading down that same path.

Agree to disagree, at least any time in the next decade. I just don't see anyone ever getting that kind of quality out of extruders. That tech has limits. It will get better, but nowhere near the quality you can turn out with traditional machining for the vast majority of applications. Precision sintering machines are much better, but require numerous parts that cost over $1,000/ea. They cost that much because they have to be made the old fashioned way. They're precision machined and ground with very pricey equipment using good (expensive) materials. SLA is showing a little more promise on the affordability front, because it's not quite as tech-intensive and doesn't require high-powered lasers or an oxygen-depleted build chamber, but once again they're bumping up against hard limits cost-wise. Precise motion components cost real money, and there's no way to get around it right now. Rule #1 of business: you can't sell things for less than it costs to make them.

I think you are only looking at the downside of a 3D printed part here.

Not at all. I think it's fascinating. I have the education and technical chops (and access to software) to make use of at least some of its benefits. Unfortunately to get the full benefit, I'd need to get my hands on equipment that I might never have access to. I'm also going to lose access to the $50k worth of software I'm using in about 6 months. Only companies like Honda and Boeing can afford current state-of-the art 3D. That situation is almost guaranteed not to change any time in the next decade. Like I said in my initial post in this thread, I wish I were wrong. I just don't see the industry headed that way at the moment.

It's split into two tiers. On one hand, you have true industrial grade equipment/software that is not coming down in cost but gradually getting better quality. It's not accessible to the general public (or even most businesses) in any real sense. The current tech won't be for some time. On the other hand, you have consumer-level stuff that's coming down in price pretty rapidly but might not ever quite get there quality-wise due to limits in working with extruded thermoplastics.

Have you ever been inside a MakerSpace facility?

Have the keys to one. I fixed one of their printers, and in return the wonderful lady who runs the place threw me a set of keys. I am using a current-generation $1,200 printer (one of the highest rated products in its price range) on a project. It's the cheapest way I have of making the parts. That's only because I don't have to charge myself for my own labor.

Hope I'm not boring you with too many details here. If I included my time in the project costs, those parts would not be cheap at all compared to standard machining. If I'd used aluminum, I'd have to pay for machine time on things like a hydroforming table, and CNC mill, but they would be nearly no-touch. All I'd have to do manually is tap a few threads and I'd be done. Using extrusion, I only have to pay material cost. The downside is that I have to do many hours of actual manual machining to finish the parts. The only real benefit I get is a relatively small weight reduction compared to aluminum. It's a weight-sensitive application, so that is nice.

The reality is for $2000-$3000 I could probably build myself an entry-level CNC mill that would turn out better parts than any extruder ever will, and give me the option to use solid aluminum or steel. Maybe an extruder would be a nice addition to the shop if I already had a CNC mill and enough extra money laying around for it and a home copy of Solidworks or something like it. But back to reality. I have to finalize the drawings for a boatload of parts tonight, so I'm checking out for now.

FRegards