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Equipment designed to military specifications faces extreme
environmental conditions, and in the case of one Tablet PC, it included
being waterproof and operating in 70 deg. C ambient.
The manufacturer initially designed the ruggedized system as a sealed
enclosure containing a CPU board, PC board, two batteries, hard disk,
touch screen, speakers, GSM module and finger print sensor. To measure
the system's thermal performance, the company engaged India-based design
consulting firm, Waveaxis. Using Coolit, Waveaxis performed thermal and
flow simulations that demonstrated the design could not survive the
rigors of MIL-STD 810F.
Waveaxis redesigned the system, creating effective conduction paths
through a combination of heat sinks, heat spreaders, gap pads, and
finned heat pipes. The consulting firm's design even allowed a small
amount of forced convection through limited venting without sacrificing
the unit's water-proof characteristics. With the aid of Coolit, the
firm optimized the heat sink geometry and placement of the heat sinks,
vents, fans and ICs. No physical prototypes were needed. The entire
project achieved its design goals without building a single unit,
thereby saving the client thousands of dollars in prototyping and
physical testing costs.
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