Open Bionics 3D printed prosthetic hand

Why Marginally Clever Robots doesn’t make Prosthetic Arms, Hands, Legs, or Feet

Prosthetic arms, prosthetic hands, and prosthetic limbs are useful and good… but Marginally Clever Robots won’t be making them any time soon.  Read on to find out why.

Open Bionics 3D printed prosthetic hand

Prosthetic arms have hit the current technology ceiling

There’s little room to improve.  Battery technology isn’t changing, bearings aren’t changing, and the motors which drive the fingers aren’t changing.  The off the shelf parts used to build those arms aren’t getting any smaller or stronger.  Every custom part is one more problem for manufacturing.

Prosthetic arms require too much customizing

Just as no two fingerprints are the same, no two limbs-that-need-an-upgrade are the same.  Custom work is done by an expert, which means it’s expensive.

The prosthetic arms market is too small

Take the cost to develop an arm.  That’s time building one-of-a-kind prototypes that might never work.  Maybe they never leave the sketchbook, maybe they never make it out of the CAD program, maybe they get all the way to the first test before some subtle flaw is discovered.  Every one of those is parts, custom manufacturing, labor, and more. We’ll call that cost A.

Take the total number of people who can use that arm, B.  Your average cost to develop an arm is A/B.  If every arm is unique (see above) then B might as well be 1.

Take the cost to build one of these arms, including salaries, insurance, marketing… everything, C.  Your average price per user is (A/B)+C.  Most people haven’t got that.  That’s why prosthetic research companies are often hunting for funding.  Win all the good Samaritan awards you want!  It won’t keep the lights on.

In some cases costs can be shaved if the arm is made in parts: specializing in only hands, and then making custom forearms.  That reduces A somewhat.
image courtesy of

What about open hardware prosthetic arms?

The work could also be done as open hardware.  People of all skill levels meeting on the internet, giving of their free time to share ideas and openly solve the problem.  That’s great because then A and C come way way down.  This has been done, and there are several open hardware 3d printed prosthetics available (see picture above for an example).  Which segues into the next point,

Marginally Clever Robots wouldn’t make a 3rd rate prosthetic arm

Even if we were to say “money isn’t important, time isn’t important, just make an arm or a hand”… then we’d still want to make something useful that satisfies and lasts.  There’s an old saying, “cheap, fast, good: pick two.”  If we say no to cheap and fast that still leaves good.

You may have seen feel good “and on a lighter note” news bits about 3d printed hands for kids.  They look good in photos, and even sometimes get a celebrity involved.  Unfortunately they last maybe a couple of hours of a real child’s destructive enthusiasm.

Other companies are better positioned in the market

As an example, Bebionic know what they’re doing and make a modular arm that can be used as a hand or as a full elbow-to-wrist solution.  We wouldn’t compete with them any more than we would try to make a better cell phone than Apple.

bebionic prosthetic hand

At Marginally Clever Robots, we believe there are easier ways for us to make robot arms that will help people with disabilities rejoin the work force, feel empowered, and help themselves.

What can you do?

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