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Medical manufacturers find balance in design

By: Bill Bregar

May 22, 2014

CLEVELAND — Ergonomic design of medical furniture like tables for surgery or CT scans involves the study of the human body, industrial designer Mike Maczuzak said at the Plastics in Medical Devices conference.

And one-size certainly does not fit all.

“Especially when designing medical devices, it’s really important that we keep trying to find ways to accommodate more people,” he said.

During the Cleveland conference, Maczuzak teamed in a design session with Dan Snyder, technical sales engineer at Plastikos Inc., an injection molder and mold-maker in Erie, Pa. Snyder told attendees how they should approach plastics parts manufacturers for prototype molds and for full-production tools.

Maczuzak is president of SmartShape Design Corp. in Cleveland.

He gave an example everyone in business understands: airplane seats in coach. He explained how airlines make their seat-design decision — a numbers game, to fit as many people on a flight, and make seats with basic comfort to the largest number of people. There’s a tradeoff, as any taller person knows after spending a flight with knees crushed against the seat in front.

Medical product designers also often use this compromising approach. They split the difference, he said, and make chairs, tables and other furniture that is tolerable but not comfortable. But people in hospitals have to be there — it’s not voluntary — and they deserve better, he said.

Maczuzak displayed slides of a TransMotion motorized chair on wheels, with built-in power that converts it into a wheelchair that can fit people with different-sized bodies, and then become a stretcher. A person could start in the hospital waiting room, go through testing and treatment, all in the same chair.

Another example is hand-held surgical devices. On one device, SmartShape made about 30 basic models, then narrowed it down and turned out full prototypes complete with levers and springs. Designers got feedback from surgeons. The goal: a device not too big for small hands and not too small for big hands.

Snyder said he asked Plastikos’ medical customers what issues they faced with suppliers. A common remark: original equipment manufacturers and mold makers must collaborate as early as possible.

“What it’s going down to is, when you’re taking that CAD model to something you’re going to make tens of millions of parts out of, you need effective communication,” he said.

Key issues are how to gate the mold, options for mold cooling, lead time and, most importantly, establish exactly how the customer will validate that tool. Once a mold goes into production, pulling it out to make changes is much more difficult, Snyder said. Often medical molds have complex slides and two-shot capability.

OEMs need to create a checklist covering the entire process, he said. And Snyder suggested visiting a mold supplier early, to meet the people who will design and build the mold.

Early communication also helps to avoid rushing the tool through. Snyder pointed out that many mold components, not just the cavity, have to be custom made — one reason molds seem to be so expensive. And it’s important for the mold-maker to build a mold for easy maintenance, allowing, for example, the replacement of a frozen insert in the future.

“Trying to retrofit a mold down the road to be easier to maintain, is always hard,” he said. “Following those design strategies will also save you money as well.”