Wednesday, June 22, 2011

SensAble CAD tech powers rapid prototyping for prosthetic parts

By Lynette F. Cornell

Losing a nose to cancer is bad enough, but the process to get a new one can be a significant pain itself. In most cases, any unfortunate person being fitted for a prosthetic part must sit still for hours as a technician applies cold plaster to the part’s intended location. The patient then has to wait weeks for the mold to be turned into the part and return to the doctor’s office to have the piece fitted, hoping all the while that the piece will fit right and look natural. If it doesn’t, the patient must wait for the part to be remade with the needed adjustments and return to the office weeks later for another fitting check. That’s the old way, and it’s completely unnecessary with the ability to digitally scan and sculpt organic designs, according to 3-D design software and hardware developer SensAble Technologies Inc.

Founded in 1993, the Wilmington company has developed tools that allow design engineers and surgeons to interact in a digital world that heavily mimics real world conditions through haptic feedback. Technicians designing a prosthetic part with the haptic device experience the same physical properties of the materials they are digitally manipulating on-screen. With SensAble’s Freeform software, this means being able to craft a piece, such as a prosthetic nose or ear, completely customized to the person’s face but with the ability to quickly visualize how it will look on the patient and adjust as necessary.

Working digitally also relieves patients of sitting through a plaster mold-making process, a procedure that may not be practical for patients at certain stages of a disease. With a photogrammetry scanner, the doctor can touchlessly map the geographic contours of where the part will be located, creating an exact fitting for the part. The scanner also can be used for mirroring a remaining part, such as a hand or ear, to replace the missing one. According to Kevin Atkins, a corporate applications engineer at SensAble, the software also analyzes the manufacturability of each piece, ensuring the designed part can be physically produced. Additionally, he said, the digital files can be conveniently stored for future reference or part reproduction, whereas physical prototypes take up space.

SensAble has shipped more than 9,000 haptic device units, which are used in a range of applications, from modeling to virtual practicing of surgical procedures. As for competition, a few companies are developing similar modeling technology, particularly in the dental market, but digitally designed prosthetics are rather new, according to Joan Lockhart, vice president of sales and marketing at Sensable. “The majority of it is still made by hand,” Lockhart said.

SensAble was born out of technology developed by Thomas Massie and Kenneth Salisbury while enrolled as undergraduate students at MIT in the 1990s. In 2005, it launched a dental division, which uses the modeling system to design custom dental pieces, ranging from a single tooth to a set of dentures. Last month, the company bumped up its previous funding round from March of last year by an extra $1.3 million for a total of $3.3 million to expand its work in the dental market. Until its move to Wilmington last summer, the company was headquartered in Woburn. While medical modeling is one of SensAble’s largest market segments, its customer base spans industries from robotics engineering to toy design.

The Chamberlain Group in Great Barrington has been using the design system to make lifelike replicas of human body parts and systems, which are used by surgeons to master medical procedures before they work on a patient. The 12-year-old company began using SensAble’s software a few years ago to supplement their traditional use of CAD for the industrial design aspect of their products. The company has gained an increase in flexibility from using the SensAble system as well as more ease in scaling production, according to Lisa Chamberlain, the company’s managing partner.

“It’s much more time effective, especially in an iterative process,” Chamberlain said. Initially, the Chamberlain Group faced some hesitation from designers who were reluctant to switch from using the physical medium they were accustomed to, but eventually, the software’s ease of use won their approval, according to Chamberlain.