Problem solving to create the perfect overlay

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By Dean Karousos | Sep 08, 2015
Medical custom manufactured overlay

During a recent conversation discussing problem solving capabilities at GMN, a project worked on a few years ago with Sotera Wireless was brought up. This project was unique because a standard polycarbonate, typically used for overlays, didn’t meet Sotera’s requirements. To overcome this challenge, our team needed to think outside of the box to create a solution.

Sotera Wireless, a leader in mobile patient monitoring medical devices, was looking for an overlay for one of their medical devices. Along with DD Studio, an industrial design studio hired to design the device overlay, GMN needed to find an overlay solution with optical clarity, impact resistance, and chemical resistance.

One of the greatest challenges with this project was finding the right material for the overlay. Originally, the plan was to use an injection molding process, but this was found to have problems when the material flowed around the small holes. Next, a laser was chosen to cut parts from sheet-stock, but this process introduced its own challenges. First of all, the chemical resistance was a concern on the cut edges. In addition, while an acrylic laser cuts cleaner and better than a polycarbonate, it isn’t as durable and is prone to chip or shatter on impact.

To solve these problems, a unique material was used, Eastman’s Tritan MP 100, a proprietary impact resistant co-polyester. The Eastman co-polyester material provides a cleaner laser cut edge than polycarbonate, and is available in 0.060” sheets, the desired overlay thickness. Lastly, an Exxene hard coat, the Flexform 200, was applied to the overlay.

One more challenge was faced during the project: identifying a metallic ink without metallic flakes. The ink could not contain any metal because it would interfere with IR scanner readings. GMN spearheaded the research and development needed to find a solution that satisfied both Sotera’s functional and cosmetic requirements.

Sotera Wireless was overwhelmingly pleased with the product. GMN’s cost effective solution not only provided design solutions but technological innovations as well. This overlay is a good example of the benefits of vendor consolidation, innovative processed and a solution-based approach.