3D printed hand to play the guitar

Juan and his sister Andrea Monroy launched a brand new online marketplace for 3D design and 3D printing called 3Dglück, which aims to provide 3D creation services to people across Latin America. Diego, a rock n roll lover, was born with a congenital amputation of his right hand.

The boy used other prosthesis as a child, but they never worked very well for him. They tended to break, be uncomfortable or featured a mechanical grip that was hardly worth all the trouble, and by the age of eight he decided that he didn’t want to have a replacement for his hand anymore.

That all changed when Diego met Juan. The designer thought 3D printing would be the best solution. “After talking to him and his family Juan Camilo understood their frustration and the fact that most of the time prosthesis are not exactly made to meet the needs of a specific person," Andrea said.

Diego was only interested in a prosthetic hand that would allow him to do different things, in his case, to play guitar.

“There is a quote by Louis Borges that says “I am not who I am, I am what I do with my hands”, that is exactly the way Diego perceives life. Why would someone want an expensive prosthesis if they cannot do extraordinary things like playing piano, guitar or take a picture? Why is the main goal covering the problem?", Andrea said.

Playing the guitar requires very exact motions and pressures on the muscles and cartilage of the human hand, so there’s a lot more to it than adding a pick to a plastic prosthetic. They therefore heavily relied on a book by Adalbert Ibrahim Kapandji on human physiology, "The Physiology of the Joints volume 6", which describes the detailed pronation and supination movements of playing a guitar. With this knowledge, they developed six prototypes, eventually adding a series of springs that enable the necessary pick movements.
So, the result was a different 3D printed hand, with only two “fingers”. It is worn with a non-skid fabric underneath to ensure a secure fit, and can be controlled using the pronation and supination movements of the arm.

The prosthesis had a total cost $300. And now Diego can play guitar.

Adapted from: https://www.3ders.org/articles/20150202-17-year-old-learns-to-play-the-gu...

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