Demand for micro-medical parts fuels growth at MTD

Powered by rising demand from the medical device industry, sales at MTD Micro Molding (Charlton, MA) will grow 20% this year from the $5.3 million recorded in 2010, CEO Dennis Tully told in an interview.

And that's a slowdown.

"Our annual sales growth has been as high as 60% in the previous five years because of our focus on micro parts for the medical market," Tully said.

Dennis Tully of MTD Micro Molding
A focus on miniature medical applications is fueling growth at MTD Micro Molding, says president Dennis Tully.

By the end of the year, MTD will complete installation of a 1200-square-foot Class 8 cleanroom that, once filled, will increase the company's number of molding cells from 10 to 18.

One of the biggest challenges the company faces is convincing design engineers at medical device manufacturers how small they can go. "We regularly have meetings with engineers to educate them about exactly what is possible. They are generally surprised at how small they can design components," commented Tully.

So what is the state of the art in micro?

"A few years ago we said we had molded the smallest part ever at three decimal points of a gram, and no one challenged us. The parts we are making now are a fraction of that size - basically a speck of dust. You need a microscope to see it." Micro-molded parts typically have thicknesses under 0.040-inch at the widest point. Wall thicknesses can be under 0.001-inch. Tully said he doesn't know what the size limit is for a molded part.

Another challenge, of course, is making those parts consistently to specification on a large scale.

Tully said that MTD buys standard injection molding machines (from Sodick) and then adapts them to meet the company's specific requirements. Equipping the rest of the cell has been a problem. "The auxiliary equipment has not kept pace with the requirements of micro molding," said Tully. MTD's engineers specially configure dryers, for example, and also do a lot of work on heating and cooling of the tools, which it makes itself.

MTD in fact was founded in 1972 as a mold manufacturer called Miniature Tool & Die Inc. by Richard Tully, who retired in 2008. Dennis, his son, bought the company and changed the name last year to MTD Micro Molding to reflect the company's new capabilities. More than 95% of the company's business is in the medical field, which is unusual. Other major micro-molders in the U.S.A. also, or primarily, serve the electronics market, which has also moved to miniaturization.

Components made by MTD include fixation devices, fasteners, and parts used in micro-endoscopes and automatic-insulin-pumping mechanisms for diabetics. Customers include Abbott Laboratories, Boston Scientific, Cardinal Health, Medtronic and St. Jude Medical.

Resins used range from polypropylene to PEEK, and include a number of heat-sensitive bioresorbable materials, such as proprietary compounds of polylactic acid (PLA).

Tully said that MTD expects to buy more equipment to expand capabilities next year. One new capability that may be added next year is liquid silicone rubber molding.


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