3D Printed Prosthetic Research

As a university researcher, it often takes a long time until I can actually share my work publicly. As a result this blog often only tells part of the story, for example I recently posted about 3D printing a prosthetic hand by e-NABLE. What I didn’t say is that this was part of research into adapting the design to perform different tasks. Recently undergraduate product design student Cory Dolman worked with me to prototype some new concepts, and his work has been picked up by UTS who created this great video about his process and the ideas we’ve been bringing to life. You can also read all the details on his blog which was maintained during the project with me here.

For anyone who is yet to realise the opportunities of 3D printing technology, hopefully this video goes some way to showing how quickly designers like Cory and myself are able to iterate designs, constantly testing our ideas and expediting the design process. We hope that as we refine these designs, we will be able to share them back into the e-NABLE community, and allow anyone with access to a 3D printer to not only benefit from the prosthetic, but also continue to iterate and improve it collaboratively. This is what excites me about 3D printing – it’s not just about the technology, but what it enables.

– Posted by James Novak

Advertisements

Oh That’s Handy – 3D Printed Prosthetic

20180114_e-Nable Prosthetic Hand

If you’ve been paying any attention to 3D printing over recent years, no doubt you’ve seen at least a few 3D printed prosthetics. From the Iron Man prosthetic arm to the prosthetics being 3D printed for our animal friends, 3D printing is ushering in a new generation of low-cost, customisable prosthetics. Perhaps you’ve even seen my build of the fully robotic InMoov hand which has been documented on this blog.

At the extremely affordable end of the spectrum for humans, Enabling the Future (also called e-NABLE) is one of the most well-known names, developing a range of  open source prosthetics since 2013, which can be freely downloaded, printed, assembled and sent off to those in need. As part of my research I have wanted to build one of the e-NABLE hands for a while now to understand more about them, particularly in comparison to the more complex InMoov robot arm. As pictured above, I’ve finally got around to printing the Phoenix v2 hand, which is wrist actuated to open/close the fingers.

When you look at all the details, it really is a clever design which is optimised for 3D printing on a desktop FDM machine, with almost no support material or waste, and tolerances that fit really well together. Anyone with a 3D printer could assemble one of these, most of the non-3D printed parts can be sourced at a local hardware store or found in your shed (screws and fishing line). The instructions are very clear, and there are loads of videos to help demonstrate the assembly process and how some of the technical aspects of the hand work. Because I printed in ABS rather than PLA plastic, the only small hurdle I had was in the thermoforming process of the gauntlet (the bent white piece that mounts to the users arm), which required me using a strip heater in the university workshop. If you find yourself in a similar situation, you can check out the details which were posted in one of my previous posts. However, I recommend using PLA if you have the choice to make this part easier, only requiring some boiling water as demonstrated in this video. In itself, this is a really cool technique that I will use in the future to create stronger parts; you can always learn a lot from 3D printing other people’s designs.

Overall the e-NABLE community really has done a great job in refining this design over the years, and I’m already working on some of my own iterations which will hopefully be fed back into the e-NABLE community in the future. If you’re looking for a project to build and learn from, or potentially getting involved in the community and building hands for people in need, Enabling the Future is definitely worth researching.

– Posted by James Novak

Thermoforming 3D Prints

20171113_Thermoform 3D Print

Sorry for the blogging silence, this is the longest break I’ve had since starting a number of years ago. Long story short I’ve made a big move recently for work and am only just starting to get back into printing and making new projects. If you follow my social media, you’ve probably noticed some new things starting!

One of the projects I’ve wanted to play with since previously building the InMoov robot arm is the Enabling the Future prosthetics (aka. e-NABLE). This week I 3D printed and built most of the Phoenix v2 hand, which of course is open source and free to download. A really inspiring company, and a vastly more simple design compared to the electronic InMoov! Some of the pieces, which I printed on an UP Mini 2 in ABS plastic, can be seen above. I’ll post full details once I get it up and running, just waiting on some elastics for the fingers. The gauntlet piece, which attaches to the users forearm, is printed in a flat position and then bent into a C shape afterwards. This is a really clever idea for providing the strongest functional part with optimal layer orientation. But how do you bend a 3D print?

Well the instructions from e-NABLE require dipping the piece in boiling water for a few seconds to make it pliable – if you 3D print in PLA, which has a lower melting temperature than ABS. Check out the video here. However ABS is not really going to be affected by boiling water, and just to make sure I did try this technique with my first print. It did get a bit of a bend, but mostly a snap!

For print #2 I instead found myself a strip heater in the workshop, which is perfect for heating a nice clean line and normally used to bend acrylic sheets. A few seconds on each side of the print and it bent perfectly without de-lamination or splitting, and was easy to re-heat to make small adjustments to fit with the hand print. This is a technique I’d never thought of using, but has really given me a lot of ideas for creating 3D prints which are post-processed like this into a stronger shape than if they were 3D printed in their final more complex form. I think some of the simple enclosures I’ve made in the past could be much stronger if considered more like a sheet-metal part, although then this begs the question why not just laser cut the design? Well in the case of this e-NABLE prosthetic, there are some 3D details for snapping in other pieces, which could not be done using a 2D process like laser cutting. This would be important to consider if using this process with 3D printing, but it’s certainly an interesting technique worth further experimentation.

If you’ve done something like this yourself, or have ideas for thermoforming a 3D print, leave me a comment.

– Posted by James Novak

InMoov Custom Mobile App

It’s been a while since posting about the InMoov robot hand I started building last year. Previously I had everything assembled and was using some direct controls in Grasshopper (plugin for Rhino) to test and tweak the movements of the fingers and wrist (click here to see the last video). That was fun, but not as fun as being able to control the fingers wirelessly from across the room!

Using MIT App Inventor, I’ve created a very basic mobile app that now allows the fingers and wrist to be controlled on my phone using a Bluetooth connection to the Arduino board. It’s nothing fancy right now, just some simple sliders that control the servos, but now that the basics are working some more automated movements could be set up eg. by using the built-in sensors of the phone, movements could be controlled by simply tilting the phone.

20161203_InMoov Display

In order to display the working InMoov hand at the CreateWorld Conference last year, I  also built a display box from plywood since the arm is not really attached to anything and there are a lot of electronics dangling around that are a bit too messy for display. It actually makes moving the hand around and working on it quite a bit easier now since it’s raised up as well. If I had files for this case I would share them, but I went old-school for this one and just created it freehand with a jigsaw – I’m not completely reliant on digital manufacturing (yet!). Inside the box on the right are all the messy electronics, and a hole for the Arduino USB cable to reach through to connect to computer when needed.

I’ve also 3D printed a stamp with my name and the edditive logo to “tag” this project. Using 3D printing to make custom stamps is something I wrote about in one of my first ever blog posts, click here to take a trip back in time. It’s always the little details that bring a project to life for me.

– Posted by James Novak

InMoov Robot Hand First Prints

20160812_InMoov 3D Prints

If you’re already following my Instagram you’ve had a sneak peek at one of my side projects – to build the arm/hand for the InMoov robot. No small project! InMoov is the world’s first open-source 3D printable life-size robot, and you can find some excellent instructions and all the files on the InMoov website, a fantastic credit to Gael Langevin the creator of this robot.

Above you can see the first 3D prints I’ve completed for the arm, all printable even on the small print bed of the UP Plus 2. Some of the prints are also done on my Cocoon Create. At a guess it’s taken about 25-30 hours of print time to get the parts shown above, and there are still plenty more to go, so this isn’t a project for the feint of heart. But it is a great challenge that combines 3D printing with electronics and some understanding of mechanics, like an advanced version of Lego.

20160814 InMoov Details

There are other similar open-source projects out there, such as Open Bionics or e-NABLE, but I chose the InMoov because the instructions seem really clear and detailed (very important for a build like this!), and there is a good level of complexity in the movements of the hand. Check out this video to see some of the movements. Hopefully once I get the hand up and running I can have a play around with the design and the method of controlling the hand, but for now it’s just about getting the hand built and working. Keep an eye out for the progress, hopefully with some of the electronics installed once the servo’s arrive from China.

– Posted by James Novak

Giving the Finger to 3D Printed Prosthetics

20160410_Prosthetic Finger

I’ve always wanted to try 3D printing one of the great open source prosthetic hands that frequently pop up in my news feed, and I have finally found an excuse, and a little bit of time, to dip my toes in the water with this prosthetic finger. This is the freely available Owen Replacement Finger, available from the well known 3D printed prosthetic company Enabling the Future. While the design is admittedly quite clunky, it does work, and it is somewhat customisable using the Customizer feature of Thingiverse to fit your hand/finger dimensions.

All the pieces printed in 2-2.5 hours on my Cocoon Create printer, with only a couple of the small details not printing correctly (in particular the guides for the fishing line on the back plate). But nothing critical. Add a small length of elastic cord and some fishing line and you have a basic moving finger. Many of the parts are designed to be fixed to a glove so that when you clench your fist, the finger bends, but for now I’m not interested in creating an extra finger for myself or anything – it’s just a trial as I lead into a research collaboration at university to look at finger prosthetics for some real life patients.

From this small print I can see why the full prosthetic hands make a great project – it’s fun to bring something like this to life with movement that begins to replicate our own human anatomy. Hopefully there will be more like this to come!

– Posted by James Novak