Today 3-D printing technology is changing the prostheses field, allowing engineers and physicians to develop fully customized prosthetics and even DIY assistive devices for patients in need.
Now a team of student engineers from Rice University has developed a device that will help ensure that children who fashion 3-D-printed prosthetic hands get the most out of their wearable.
The printed palm, created by the group that calls itself Carpal Diem, is a testing suite that validates how well 3-D-printed hands transfer force from the wearer, in this case for children born without a fully formed hand, to the prosthetic intended to help pick up and manipulate small objects.
While 3-D-printed hands are working wonders for children who need them, the Rice students believe that 3-D-printed prosthetics aren’t as efficient as they should be.
“Children born without full hands are forced to adapt to the world and figure out how to go about their daily routines,” said Amber Wang, Rice student who worked on the project. “If a prosthetic hand is not absolutely perfect in its function, the child will probably discard it and return to his or her own adaptive ways.”
The suite consists of a motorized wrist-and-palm assembly that can move up to 60° in either direction; a set of objects that include a cylinder, a sphere and a rectangular prism with embedded force sensors; and a control program with a graphic user interface.
To use the palm, an operator must use the program to bend the wrist and close the printed hand’s fingers and thumb around an object. The sensors in the object send information on force strength and distribution to the computer.
“If a kid has to put in five pounds of force to only get one pound of grip, that’s a lot of lost efficiency because of how these hands are designed,” said Rachel Sterling, mechanical engineering student who worked on the project. “Until we reach a force efficiency of 100 percent, the hands aren’t going to be useful.”
By the end of the year, the team members will give the first prototype of the testing device, along with a detailed protocol for its use, to their mentor, Dr. Gloria Gogola, a pediatric hand surgeon at Shriners Hospital for Children—Houston, who has worked with many Rice engineering teams in recent years. Eventually they would like to publish the specs for those who want to develop the testing device on their own.
The printed palm was originally designed as part of the Rice students’ senior capstone design project, which is required of most Rice engineering students.