When Thales Navigation, a manufacturer of GPS systems, called Wagic Design (http://rbi.ims.ca/3846-560) in Los Gatos, CA, it had a problem—some of its portable GPS units required many individual modules and cables to set up a "package." And the portable equipment wasn't easy to configure and carry into the field. How could Wagic help with a new design?
Wagic actually offered several alternate designs. "The original design called for modules and cables, but Thales wanted to reduce complexity and cost. So, we eliminated the cables and created a modular design that users can quickly expand," says Neal Whitsett, Vice President of Engineering at Wagic.
Even though Thales supplied the GPS electronics and technology, Wagic's design team determined sizes and shapes of the printed-circuit boards, what connectors to use and where to place them, and the types of seals needed to provide weather protection. That last task involved keeping a GPS system dry even after submerging it in 1m of water for 30 minutes. "Thales furnished a 'marketing specification' that included plenty of restrictions and criteria we had to meet," says Whitsett.
One of the biggest challenges came in getting the best package—a case made out of cast magnesium—for the modules. Wagic had a vendor in the U.S. that could produce die-cast magnesium cases, but its capabilities couldn't meet the designers' exacting specifications for the new product. Through connections at Thales, Wagic found a supplier that uses relatively a new process—thixo molding—which offers better control over wall thicknesses. Joe Gallegos, Design Program Director, took responsibility for the case design.
The molding company hadn't done anything this complex so it learned much during the development of the case. "The complexity came when we needed to do the volumetric calculations: How much magnesium gets shot into the part and how do we increase the flow properly? Answering those questions took tremendous effort," says Whitsett. "At first, the injection time was about 10X off what the process finally required."
Sealing the case and the modules also presented challenges. In some areas Wagic used double tongue-and-groove construction with intermediate gaskets. Engineers also applied conventional sealing methods, but often had to adjust seals to meet unexpected changes. If parts didn't come out of a mold exactly as specified, designers had to figure out how to change the seals but still use existing tooling. In some cases, they went from a gasket seal to a UV-cure adhesive seal.
From Many, one: Designed for Thales
Navigation by Wagic Design, the modular Z-MAX GPS system lets user select
the modular functions they need. Special packaging makes the unit light
weight and weather resistant.
Unlike some design firms that concentrate on packaging, Wagic's team also handled some of the electronic designs, including the battery circuits and the battery charger. Idriss Ruiz, the director of Mechanical Engineering, tackled the design of the modular antenna, which fits on a handheld unit or on a backpack system. The design team also took responsibility for all the module connectors and interconnections.
Neal Whitsett, VP of Engineering for Wagic Design was a member of the start-up team of Delfin Systems and Edge Diagnostic Systems. Prior to Wagic, Neal spent 20 years working in product design.