Originally Published MPMN October 2002

PROFILE

Development of PDA-Style Device Gets Helping Hand from Molding Firm

Design for manufacture services contain costs

Zachary Turke

When Medtronic Inc. (Minneapolis; www.medtronic.com) decided to rethink the design of its programming units for neurostimulators and implanted drug pumps to achieve greater mobility, the company took the natural first step and approached a design firm. IDEO (Palo Alto, CA; www.ideo.com) and Medtronic employed advances in handheld consumer devices to successfully reduce the size of the two 20-lb briefcase-sized programmers and combine their capabilities into one unit. Satisfied with the design of the universal palm-sized N'Vision device weighing just 1.2 lb, Medtronic enlisted injection molding firm Phillips Plastics Corp. (Hudson, WI; www.phillipsplastics.com) to help turn the prototype programmer into a manufacturable product.

"I think the reason we were chosen is because, unlike many other injection molders, we offer design for manufacture services," says Kelli Varco of Phillips. "Oftentimes, design firms just consider the design in the abstract, not taking into account all the factors that affect physical production," she explains. "Because our design teams intimately know the production processes, they can often recommend design changes that will improve the product."

One such recommendation involved a component on the unit's bottom housing used to hold the stylus when not in use. Similar to a pen in shape, the stylus is a long accessory used to enter data into the programmer's LCD. The original design for the holder for this device called for a snap-fit feature that required complex tool construction for slides and lifters. Phillips's design team recognized that this feature was not cost-efficient and recommended a two-part assembly that accomplished the same task without requiring secondary assembly.

Containing an LCD touch pad and infrared lens, the programmer's top housing also benefited from Phillips's design for manufacture services. Originally, ribs or snap-fit features were specified to give this component the required rigidity. Space limitations made these options impractical. After reviewing several alternatives, Phillips recommended its Thixomolding process as a solution. Employing shearing force and heat, this injection molding process uses magnesium instead of thermoplastics to produce strong lightweight components. The new design produced a top housing that resisted twisting and withstood drop tests of 40 in.

Due to early involvement, Phillips was able to help finish the programmer design, build tooling, and deliver the first samples to Medtronic within 12 weeks. At final tally, the injection molder produced 16 device components, including the top and bottom housings, the telemetry module cover, the actuator buttons, and the stylus.

In addition to design for manufacture and injection molding services, Phillips performs overmolding, shielding, program management, material selection, decorating, and assembly. "We can take almost any project from design through manufacturing," concludes Varco. "And with our wide range of in-house capabilities, we can always make sure our customers' products are manufactured using the optimal processes."

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