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Engineering Team Using 3D Printers to Test Health Device Designs

Sundar Krishnamurty

Doug Eddy with 3D printer

A team of researchers in Sundar Krishnamurty’s mechanical and industrial engineering laboratory is putting a couple of new, high-end 3D printers through their paces now in their temporary location in Elab II while they await the building of new facilities at the Life Science Laboratories (LSL), expected to be finished in 2016. See News office Story.

The short, squat Connex 350 by Stratasys can handle two different materials with different mechanical properties, for example one more flexible, the other more rigid. The user pours a semi-liquid goop in, and shaped objects come out.

The 6-foot-tall, slim Formiga P110 by EOS uses “selective laser sintering” technology and can fabricate items in both metal and plastic. The user puts in a white powder made up of nylon particles, which in the machine are sintered by the laser. Sintering means the surface is heated just enough so it gets sticky but does not melt.

Krishnamurty is the site director for the Center for e-Design and co-director of advanced design and fabrication (ADDFab) group in his lab with Christopher Salthouse of the Center for Personalized Health Monitoring, which will be housed at LSL.

A key question, Krishnamurty says, is whether these printers can actually produce a functioning device or tool, or whether they are instead best used for making quick prototypes to test design. Their capabilities are not entirely known. So, while some members of Center for e-Design’s team are using the new technologies to make prototypes for medical device companies such as Boston Scientific, others, led by postdoctoral researcher Doug Eddy, are testing the printers’ operations and consistency, “to see if you get what you expected to get,” Eddy says. He is working with Raytheon and Siemens on hardware and software to fully explore and characterize the printers’ capabilities.

Krishnamurty adds, “All of our investigations will eventually be related to the life sciences.” He hopes 3D printing will eventually produce functioning tools.

Lucas Roman is a doctoral student in Krishnamurty’s lab who is primarily interested in the mechanical properties of objects made by 3D printers and whether they are actually useful as real tools. He will test them and work on “proof of concept” prototypes.

Frank Sup, assistant professor of mechanical and industrial engineering, studies using robotics and mechatronics for rehabilitation. He plans on using the new printer technologies to create new kinds of sensors and robotic devices for personal health monitoring and rehabilitation. He says traditional manufacturing can be prohibitively expensive for some types of personalized medical devices, but a 3D printer can affordably make a single sensor meant for use by just one person.

Tom Hagedorn is a doctoral student in Krishnamurthy’s lab and is working with researchers at UMass Medical School to develop new surgical tools with funding from Davol. He points out that tools and surgical instruments designed on a computer must be tested for ergonomics and human factors. That is, a tool might appear to be ideal on the designer’s computer screen, but when real surgeons and nurses hold a new instrument they may say it is uncomfortable and can’t be held properly. And as Hagedorn points out, “an unergonomic surgical instrument is unsafe.” Another advantage of these 3D printers is that the engineers can “print out a bunch of ideas and see which ones a surgeon likes better,” he notes.

The two new printers now being tested on campus together cost about $500,000; a third metal 3D printer will be added later. All will eventually move to the LSL for the Center for Personalized Health Monitoring by the ADDFab group.

In five years, Krishnamurty says, his group hopes UMass Amherst will be “the go-to place in the Commonwealth and in New England” for revolutionary design testing in precision manufacturing and the medical device community. (December 2014)