3D Printed Prosthetics for (realatively) cheap.

[Darmalus]

Have some good news about prosthetic limbs.

But it's what's inside the hand that makes the difference. While many 3D-printed prosthetic hands use myoelectric controls, where a sensor placed on the skin reads the electrical signals sent to the muscles underneath, the most common means of control is a relatively low-tech system of cords that pulls the fingers.

The Open Bionics hand uses a similar system, where steel cables act as tendons that curl the fingers, but these are attached to motors that act as muscles, with each finger individually powered to increase manual dexterity. This gives the wearer a much finer degree of control. The motors can also sense when movement is stopped by an object, which allows a gentle but firm grip.
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Because the hand is 3D printed, each one can be modeled specifically for its wearer. The Open Bionics team scans the arm to which the hand is to be fitted and uses that as a basis for the print, scaling the length of the prosthetic as required. The scanning process can be completed within a few minutes.

Once the design is finalised, the hand takes around 40 hours to print. And, moreover, the cost is a fraction of the higher end prosthetics. A finished hand would sell for less than £1,000 (about 1,570 or AU$2,200 converted directly) and it would cost even less if users could make it themselves using the company's open source plans and instructions.

http://www.cnet.com/news/3d-printed-rob ... son-award/

What a time to be alive.

The opinion of Grace in this video:
https://www.youtube.com/watch?v=CkNeVBaRjag

Reminds me of an older thread we had where it was mentioned that a lot of soldiers were stripping the "flesh" off their prosthetics to make them look more robotic since it was "cooler".

[biostem]

That is fantastic stuff! It's also interesting to see such people kind of moving more towards functionality, instead of just trying to make a less functional, but more realistic looking hand.

[salm]

Indeed. "Normal" Prosthetics are usually somewhere in the uncanny valley and look rather stupid. Even hearing aids, band aids and badages are often made in this sort of medical, fake skin color that simply looks sick and while I´m not a huge fan of rhinestones the shape of that arm is rather elegant.

[Broomstick]

I think those notions of cosmetics over form are fading. In the past, we couldn't build much functionality into artificial limbs, so there was focus on making things look normal. Now? You want a working hand or a natural looking hand? People are voting "working". Also, with various media portraying cyborgs and robots and stuff not only as villains but also heroes society as a whole is more accepting of the clearly artificial bits.

Hearing aids, though - why do they make those tiny things that no one can seem to manipulate, change the batteries, etc? Especially for older folks with poor visions and numb fingers? If I ever wind up with hearing aids screw that, I'll take something bigger, one of those behind-the-ear things that I can actually get a grip on and install a decent sized battery in it without needing tweezers and a magnifying glass. And screw the matching skin color - gimme bright purple with flaming red accents.

[Iroscato]

I suppose there has been a bit of a shift in the stigma attached to prosthetics. Perhaps the Iraq/Afghanistan war played a part in that with the number of soldiers needing them. The Paralympics in recent years may have helped as well.

[Simon_Jester]

I think we may see a bit of a convergence back to 'normal-looking' as the technology improves

I am (naturally) reminded of The Moon is a Harsh Mistress, where the protagonist (Manuel O'Kelly-Davis) is a miner who lost an arm in an accident and started a second career as an electrical engineer and computer technician.

He refers to a variety of prosthetics that he wears for different purposes, such as the "number three arm" with micromanipulators he uses for the kind of magnifying glass and tweezers work Broomstick refers to. ( ) And the "number seven arm," which is presumably heavy-duty in some way, we infer, because it is not something you'd want to get punched with. And the "social arm," which is designed to look as human as possible for when O'Kelly-Davis is simply going out and about and has no particular need for special capabilities.

We're not there yet- but within half a century or so it's very possible that we will. If it becomes possible to have both human form and human-equivalent function in a prosthetic arm, the trend might reverse itself. Then again, maybe it wouldn't, and I for one have no particular wish that it be pulled that way.

[Broomstick]

I think it more likely it will come down to personal choice, with a fully functional prosthetic having a "natural appearance" option as well as "functional" or "wildly decorated" options. Sort of like how hair coloring can either replicate natural shades or vivid non-natural colors.

[biostem]

Do you think the main arm part is hollow or honeycombed at all? If you are a below-the-elbow amputee, it'd probably take a while to rebuild those muscles, since you really didn't have any weight on it prior.

I wonder if it's waterproof, or would the person have to take it off prior to going swimming or such.

I wonder if they could build storage compartments or other tools into it - built in flashlight, etc.

[Napoleon the Clown]

Hollow/honeycombed: Depends on how heavy the material is to begin with. Typical weight they aim for with arms these days (whole arm) is 7 lbs or so, which is right about what the average arm weighs.

Water tolerance: I can't tell you anything solid, but it wouldn't be too hard to at least make them so you can be outside on a rainy day without problems. Getting submerged... I'm sure they can make them tolerant of that, but I honestly haven't seen anything indicating water resistance out of the latest designs. I'm guessing they advise against submerging them. Where the technology is right now, a wearer needs to remove a prosthetic arm or leg sometimes or they end up getting pressure sores. We're making strides in reducing this, but it's still an issue.

Storage compartments/built in tools: I don't see why not. Right now, though, the limbs we've got are more about replicating the function of a biological arm or leg, not being badass cyberpunk tech. I honestly would expect that to become a thing down the line, but right now I think everyone is putting more focus on making them more affordable and functional in daily use.

[biostem]

Hollow/honeycombed: Depends on how heavy the material is to begin with. Typical weight they aim for with arms these days (whole arm) is 7 lbs or so, which is right about what the average arm weighs.

Water tolerance: I can't tell you anything solid, but it wouldn't be too hard to at least make them so you can be outside on a rainy day without problems. Getting submerged... I'm sure they can make them tolerant of that, but I honestly haven't seen anything indicating water resistance out of the latest designs. I'm guessing they advise against submerging them. Where the technology is right now, a wearer needs to remove a prosthetic arm or leg sometimes or they end up getting pressure sores. We're making strides in reducing this, but it's still an issue.

Storage compartments/built in tools: I don't see why not. Right now, though, the limbs we've got are more about replicating the function of a biological arm or leg, not being badass cyberpunk tech. I honestly would expect that to become a thing down the line, but right now I think everyone is putting more focus on making them more affordable and functional in daily use.

I was partially thinking about how I keep stuff in both my right and left pockets, and trying to get something from one pocket using the opposite hand is quite difficult, so something like a compartment in the forearm might be a good alternative.

But yeah... I would see why you'd want to keep things simple - lowers costs and issues w/ such compartments possibly reducing the durability of the limb.

[salm]

I appears that they are still trying to get the weight down. Stuff in compartments would add to the weight, so I guess putting in compartments would be rather counter productive until the weight of the arm is low enough.

[Elheru Aran]

Yeah, I was thinking about that. Depending on the size of limb that needs replacing, it makes sense to have a light prosthetic so that muscles which have not been accustomed to having a limb hanging on them for some time can re-adjust with a minimum of fuss.

[Zeropoint]

Indeed. "Normal" Prosthetics are usually somewhere in the uncanny valley and look rather stupid. Even hearing aids, band aids and badages are often made in this sort of medical, fake skin color that simply looks sick and while I´m not a huge fan of rhinestones the shape of that arm is rather elegant.

I was just talking about this with a friend the other day. I don't care for the beige/pink plastic look; it just makes the bits look embarrassed about what they are. If you can't make the prosthetic pass for the real thing at conversational distances, then don't make a half-assed attempt at looking "kinda-sorta like flesh". EMBRACE the technological nature of the prosthetic. Own it and flaunt it. Give me a prosthetic with glossy black carbon fiber and gleaming stainless steel. (I'd also take a steampunk-looking arm decked out in polished walnut and brass)

The rapidly improving functionality of the prosthetics is also going to help--if someone has a prosthetic hand that can handle everyday tasks, and has some capabilities that the human hand lacks (to make up for the areas where it inevitably falls short), then wearing one won't make the user an object of pity. For an example, see those double-amputee athletes with the spring leaf feet--maybe they can't play footsie with you, but they can run faster than any unmodified human!

[His Divine Shadow]

I hope improvements continue at a steady pace in this field.

One thing that would be useful would a glove that increases grip/pinch strength. There are alot of people today with pollicized index fingers as thumbs, so they can pinch and grab things, but it's much weaker than a real thumb. Some improvement in the strength area would probably go a long ways to making life easier for these people.

[salm]

I was just talking about this with a friend the other day. I don't care for the beige/pink plastic look; it just makes the bits look embarrassed about what they are. If you can't make the prosthetic pass for the real thing at conversational distances, then don't make a half-assed attempt at looking "kinda-sorta like flesh". EMBRACE the technological nature of the prosthetic. Own it and flaunt it. Give me a prosthetic with glossy black carbon fiber and gleaming stainless steel. (I'd also take a steampunk-looking arm decked out in polished walnut and brass)

The rapidly improving functionality of the prosthetics is also going to help--if someone has a prosthetic hand that can handle everyday tasks, and has some capabilities that the human hand lacks (to make up for the areas where it inevitably falls short), then wearing one won't make the user an object of pity. For an example, see those double-amputee athletes with the spring leaf feet--maybe they can't play footsie with you, but they can run faster than any unmodified human!

Oh, I agree. Prosthetics should be treated more like glasses. There are plenty of fashionable glasses out there. The same should be possible with prosthetics and hearing aids and stuff like that.

[Napoleon the Clown]

I hope improvements continue at a steady pace in this field.

One thing that would be useful would a glove that increases grip/pinch strength. There are alot of people today with pollicized index fingers as thumbs, so they can pinch and grab things, but it's much weaker than a real thumb. Some improvement in the strength area would probably go a long ways to making life easier for these people.

Progress is going to continue indefinitely, pretty much. The US government is currently throwing money at prosthetics research because there are so many wounded veterans, and they know that there will always be more. There are a lot of other groups that throw money at it, too. There are charities that direct money toward prosthetics research, I'm sure. It's a field that is not going away. And it's more than just arms and legs. Ears, eyes, hearts...

As I understand it, right now the primary difficulty with replicating human strength in prosthetics is that the motors that can do that are often less precise. There's also power usage to consider. Batteries are still heavy as hell for the amount of charge they can hold. Improvements are being made, but that's a thing that needs considered. Reliability of parts is also of concern. We might be able to get to a point where prosthetics can exactly duplicate, or even exceed, normal function is most areas but it'll probably be quite a while. Even now, though, we're largely to the point where a prosthetic arm makes daily activities possible and a prosthetic leg lets someone walk around without much concern.


As far as customization goes: As we get better at making them I'm sure that'll become more and more of a thing. That's one thing that 3D printing offers, even. Some degree of customization. It's unlikely there's going to be a significant amount of metal used in any of them due to weight allowances, but we'll see. I could see an industry popping up that will be focused on decorations for your prosthetics.

[His Divine Shadow]

X-fingers are another interesting product, simple, body powered, just look at how naturally it moves:

https://www.youtube.com/watch?v=mhBKslv ... e=youtu.be

[biostem]

But for X-Fingers, it looks like that man still had his palm, thumb, and first segment of each finger - which while an impressive prosthetic, is still far simpler than replacing an entire hand.

[His Divine Shadow]

The X-fingers come in various setups, but I don't think that looking at it the way you are doing is correct. The X-fingers are engineering marvels in their own right and the fingers they make move and can be controlled very naturally at a very lowtech level, which is what makes them special. They're not competing with each other.

[Broomstick]

There are a lot of people missing part of their fingers or hands, and that is still an impairment even if not as bad as losing an entire arm. The more options the better, I say.

As far as compartments in artificial limbs - something small, for something light (a key, a single ID card, etc.) might be practical on some level but weight is a huge consideration. I think it could be done now, but perhaps there isn't enough benefit to offset any cost.

Would be interesting if they could incorporate a retractable charging cable along with the battery - it would useful if someone could, say, sit at a desk working but also be plugged into the wall charging their limb(s) at the same time.

[Simon_Jester]

Even a reasonably lightweight not-so-retractable cable, which you could nonetheless pull out, roll up, and stick in a pocket, would be good. That's probably already a thing though; I am almost entirely ignorant of developments in prosthetics.

[biostem]

Just how dense/durable is the 3D printed material? I'm assuming that it's more about being able to tailor the prosthetic to the individual patient, as opposed to making the lightest or most durable replacement.

I'm also assuming that there's still a good amount of manual work needed to separate, sand, and assemble the prosthetic, not to mention any finishing adjustments or fitting that may be needed.

Do most amputees wear some sort of sock or slip between the prosthetic and their stump? I can't imagine that having the plastic against your skin all day would be very comfortable or hygenic.

[Zeropoint]

From my experiences last term, I can tell you that at least some forms of 3D printed plastic can be reasonably strong in the direction of the filaments, but they have a grain, like wood, and like wood are much weaker against tensile stresses perpendicular to the filaments.

By filaments in this case, I'm referring to the strands of plastic laid down by the print head--they don't bond to each other as well as I'd believed up to that point.

[biostem]

From my experiences last term, I can tell you that at least some forms of 3D printed plastic can be reasonably strong in the direction of the filaments, but they have a grain, like wood, and like wood are much weaker against tensile stresses perpendicular to the filaments.

By filaments in this case, I'm referring to the strands of plastic laid down by the print head--they don't bond to each other as well as I'd believed up to that point.

Hmm... I wonder if using the 3D printer to make a custom mold, then using conventional injection molding or something similar, would result in a similarly priced, but more durable, prosthetic.

[Broomstick]

Do most amputees wear some sort of sock or slip between the prosthetic and their stump? I can't imagine that having the plastic against your skin all day would be very comfortable or hygenic.

Yep, usually there's some form of sock, particularly for leg prosthetics. A custom-molded socket helps a lot, but there is invariably friction, the stump changes over time (weight gain/loss, muscle atrophy, etc.), and yeah, everything needs to be cleaned on a regular basis.