Machine Design

Molding technique gets golf aid in duffers' hands fast

Rapid-injection molding (RIM) gets the credit for speeding a handheld global-positioning device to market before the start of the southern U.S. golf season.


The ProTrac device displays easy-to-read numbers showing golfers the distance to a hole, as well as center and back of the green, from anywhere on a course. It is powered by a golf cart's battery or runs off its own rechargeable battery. Its housing was first done with room-temperaturevulcanization (RTV) molding process, but though "The up-front costs of RTV seemed relatively inexpensive, it required a lot of hand tooling and refinements to create our customized product," says Tyce Fitzmorris, president of ProTrac maker Polaris Golf Systems. "It ended up being manually intensive and expensive on a per-copy cost," he adds.

Eventually RIM was the choice for creating the ABS-resin housing. The process, developed by The Protomold Co., Maple Plain, Minn. (, is fully automated and driven by the part 3D CAD model using high-speed CNC machining. The old RTV housing required three sections front, middle, and back, while the RIM housing has only front and back sections.

The RTV molding sections cost approximately $30 each, for a $90 per unit total. Final conventional molding costs ranged from $20,000 to $30,000. The RIM unit cost approximately $9 per section, with the final molding costs about $9,000 for 100 units.

Rapid-injection molding combines 3D CAD technology with highspeed CNC machining to expedite the manufacture of aluminum injection molds.

Custom housing unit for ProTrac, a handheld GPS for golfers from Polaris Golf Systems.

TAGS: Recreation
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