Three students of IIT Madras had a unique problem to solve, and it had nothing to do with engineering, but restoring the limbs of injured animals on campus.
Lokesh Kumar, head of the 3D Printing Club of IIT Madras, and a second-year M.Tech (civil engineering) student, explains that there are many injured animals on campus and 3D printing could help them. This motivated him, K Akanksh, a second-year B.Tech-dual degree (civil engineering) student, and S Ragul, a Ph.D. scholar in the department of electrical engineering, to design prosthetics for such amputee animals.
Among the many applications of 3D printing, one — that gives animals a second chance at an active life — has found significant popularity on the internet. Inspired by how the technology helped Derby, the husky born with severely underdeveloped front legs; Bagpipes, the little (blue) penguin who had its leg amputated after it got stuck in a fishing line; and Akut, a loggerhead turtle whose mandible was mutilated, the three are working on prosthetic models that can be customised according to an animal’s needs.
They have already put the idea to test, though it is still in its preliminary stages. Since IIT Madras is not equipped with veterinary facilities they had to look outside for help. “We wrote to 16 NGOs in Chennai and Bengaluru, asking if they’d be interested in collaborating with us. People for Animals (PFA) from Bengaluru replied, saying they had a macaque that was missing two limbs, and we were welcome to have a look at it,” says Lokesh.
This invitation took them to the PFA campus, where they met Dr Karthik, who helped them scan the macaque’s amputated leg with a 3D scanner. Why not the amputated arm as well? “Putting in prosthetics for the arm is a much more cumbersome process. Chances of the artificial limb working on the legs are better,” explains Lokesh.
Perfecting the design
They brought back the scans, uploaded them into 3D modelling software and designed different types of legs. So far, the club has created three designs. Lokesh elaborates. “The first one was simple: it had an oval base and a cylindrical upper portion. The problem with this was that it was too rigid at the joints. We switched to a screw-based mechanism for the second model. The screw and bolt were used to provide flexibility to move forward and backward. But on application of pressure, the cylindrical upper portion would bend at an awkward angle. ”
As the saying goes, third time’s the charm. The group added springs to the third impression to bear the shocks. In addition, they put in holes to hold an elastic Velcro strap that will keep the leg in place. “We also plan to add cushioning to make it more comfortable,” he says.
When testing the third model on the macaque from PFA they found some problems with their design. First, the method of installation needs more research. “While this macaque didn’t meddle with the straps, one can’t be sure others won’t. And since she isn’t kept in an enclosed space, other macaques can tamper with it. This is why the colour of the leg we made also needs to change. We used bright green, which can make other macaques curious about it, and they could hurt the prosthetic-fitted animal,” says Lokesh.
Flexible material
The doctor also said that the leg needs to be thinner: “It is thicker than an actual leg,” admits Lokesh. “However, if we make it thinner, it might compromise the strength of the structure.”
As a solution, they plan to use NinjaFlex flexible polyurethane, which has better flexibility, longevity, and density of 1.19g/cc as compare to PLA, which has density of 1.25g/cc. “This will make the leg lighter,” assures Lokesh.
Though this isn’t a solution that can be mass implemented as it requires customisation according to the animal, it could help many injured animals that struggle to walk. While one might think this method is expensive, Lokesh says that it costs less than ₹500 per limb. And once the scans are uploaded, it takes seven to eight hours to make a small limb. It took the team three hours to make the bottom half and another hour to print the upper half for this macaque.
If needed, they can also insert a tracking device to monitor the injured animal. Amid charges that the wildlife inside IIT Madras campus are being neglected, this seems like a fitting solution to help some of them.