ENGINEERING INSIGHT
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The console of the Orcheo XQ ultrasound scanner was formed using a proprietary injection moulding process from Midas Pattern Co.
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The Wills Watson + Associates design firm sought to update the appearance of the ultrasound scanner, so that it adheres to the common visual language shared by most products in the medical and scientific sector.
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In the months preceding the debut of the Orcheo ultrasound scanner in late 2005, Sonoscanner—the device’s Paris-based manufacturer—was faced with a limited budget and timeframe to get the scanner to the market. Using a combination of metal fabrications and mineral acrylic composites to construct the device, the company was able to move from a product-design sketch to a preproduction prototype in less than five months.
Though the first version of the Orcheo scanner was well received in the marketplace, the product’s design did not really adhere to the common visual language shared by most other products in the medical and scientific sector, says Tony Wills, cofounder of the design firm Wills Watson + Associates (London). After Wills Watson won a contract to design the console body of the next iteration of scanner—the Orcheo XQ—the design firm began to draw up plans for a new console moulding.
Following that, the firm sent preliminary CAD data to Midas Pattern Co. (Bedford, UK), a moulding specialist that has developed a proprietary metallized resin injection moulding (MRIM) process.
Wills Watson uses a digital-prototyping CAD package known as Shark on their Apple computers, but it was not a problem for Midas Pattern to import solid models from that program into their system. Midas Pattern was then able to create a composite resin mould tool directly from a CNC-machined master model. Square faces, undercuts, metal inserts, bushes, and features that normally would need to be machined were cast into polyurethane mouldings using its MRIM process. According to Midas Pattern, MRIM tooling can be modified inexpensively in comparison with instruments made by traditional injection moulding.
Brian Watson, also a cofounder of the design firm, points out that the specialized moulding process enabled the design team to specify wall thicknesses in the console without worrying about the problems with excessive shrinkage. “Shrinkage doesn’t happen with cold-pour resins in the process that Midas uses,” he says. “The resulting console also feels solid and robust to the user, which is important for the perception of a quality product,” he adds.
It was also important that the moulded parts precisely meet accurate specifications. “The console body had to mate with a touch screen, tracker ball, and PCBs that were being made by another supplier in another country,” Watson explains. “It was a huge relief when we discovered that the precision provided by Midas allowed the parts to mate perfectly,” he says. “There was certainly no time to change anything if a problem had occurred.”
The Midas parts were also colour-matched to customer specification. “Midas can apply EMC paint, an undercoat that shields electronic equipment from emitting interference, which is essential for most medical applications,” Wills says.
After a successful prototype of the console had been moulded, Midas Pattern produced a small batch of the parts that allowed Sonoscanner to exhibit the new Orcheo XQ scanner at the Medica trade show in Düsseldorf and at the Radiological Society of North America’s show in Chicago.
