The Fire Gauntlet is an attempt to make a one-shot printed glove with hinged joints, which is also my entry for the Siggraph 2010 contest. I had a concept I'd been sketching for a while that was intended to be made of individually printed steel parts, but the cost and complexity of that project was way beyond what could be done in two weeks, so I modified it to something more achievable that I thought might make a good display model.
The density-based model discount set me thinking on ways of achieving density, like arranging pieces together that would be assembled into larger models. I initially considered an architectural model with concentric shells, but the price limit of $200 was too low. I recently got access to a structured-light 3D scanner, so I decided to use that technology to help make the Fire Gauntlet concept a reality in the short time frame. The initial idea was much more ambitious than the final model ended up being, due to the engineering nightmare and general unlikelihood of accomplishing what I was trying to do. The idea morphed from a collapsible structure with sliding joints to a simpler glove that contains a few sliding joints as a test. Note the faux actuators on the back of the knuckles.
Reflective or translucent objects must be coated for acquisition in structured-light scanners. The scan was not very clean because the white talc spray I covered my hand with began flaking off, and those shapes created noise in the data. The data set is also only partial because it simply isn't possible to access all parts of my hand without moving it and destroying the scan. As it is, I had to carefully follow the rotation of a mechanized platform that starts and stops abruptly.
Here is the scanned surface I started with, and a rendering of the final design.
There are so many directions of joint motion in the hand that replicating them perfectly would be at least very bulky, and largely impossible due to the pivot points being located within the hand. Printed hinges need so much clearance that they are very sloppy and allow some lateral motion, so a very small hinge has some characteristics of a ball-joint. I decided to try to take advantage of this by using them like bushings to provide resistance as a hinge goes through it's range. By setting two hinges on a plane with a different orientation, the hinge will be inclined to stay in it's neutral position.
Minimal clearances are used, and there will almost certainly be some fusing on the first run. there are about 300 parts and I was racing to finish. Chances are I made at least one mistake, but even if I can't simply slide it off the frame and onto my hand, I am really happy with how the model turned out. I'm also thinking would help a lot if I give it a nice paint job to simulate an aged metal look. If I had the extra time and money I'd print the parts in steel and assemble them with decent fasteners. The results would be very impressive but not useful for much, except perhaps a really, really great oven mitt. At the very least I'd like to make one more generation that refines the linkages and addresses some functional issues. Also I'd like to extend the length, to make it a proper gauntlet.
To be more progressive about it, the idea does have interesting implications. In the future, with more robust materials, one could use a human-sized build chamber and print out a whole suit with specific tools and equipment designed into it. Add servos and electronics and you have a very accessibly priced wearable device customized to different tasks and individual bodies. I could see that having value for certain specialized jobs or for people with disabilities. The possibilities are really just starting to be considered, and hopefully seeing something like this in person will inspire more imaginations and help people see the potential in their own futures.
Here is the model page:
https://www.shapeways.com/model/133199/fire_gauntlet.html