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Shoe Manufacturing Snowballs with CAD, Rapid Prototyping

Spring Brook Mfg. and ATI used CAD and rapid prototyping to refine the snowshoe designs and reduce the time-to-market.



Rapid prototyping played a critical role in the design and marketing of the Saguache snowshoe, saving the company six to 12 months of process time.

When Spring Brook Mfg., Grand Junction, CO, finalized the design concept of its new Saguache snowshoe, the company turned to rapid prototyping to streamline the development process and accelerate market introduction.

Working with Hebron, KY-based Accelerated Technologies Inc. (ATI), a full service rapid prototype development company, Spring Brook was able to create and produce the new product in nine months.

Combining CAD and RP

The design concept of Saguache was first sketched by Spring Brook in AutoCAD. As the concepts were refined to a workable design, Spring Brook moved the design data to a SolidWorks' solid modeling tool.

Spring Brook took the SolidWorks model to L.L. Bean, and the two companies developed an agreement to jointly develop and market the snowshoes.

Within three days after finalizing the agreement, Spring Brook commissioned ATI to produce two selective laser sintering (SLS) prototypes of the snowshoe deck. The SLS prototypes were fabricated from DuraForm GF, a glass-filled polyamide chosen for its high definition features, smooth surface finish and mechanical integrity. The models were later used to display the product line at the first industry trade show of the season.

After producing and testing functional models of the complete assembly, Spring Brook turned its attention to the bindings.

Using the SLS prototypes, ATI fabricated a room temperature vulcanization (RTV) mold for the snowshoe deck. The rigid urethane castings were produced in a translucent green.

ATI utilized rapid prototyping in conjunction with RTV molding, a process which the company says is a fast and economical solution for prototype quantities of up to 100 parts. Within a short period of time, functional Saguache prototypes were produced for testing and a complete design review that included an evaluation of the aesthetic appeal.

Stereolithography (SLA) was used to build a master pattern to create an RTV rubber mold for the bindings. The first urethane prototypes were cast in a Shore A 80 material that mimicked the soft-touch, low durometer production bindings. After evaluating these prototypes, a second set of binds was cast in Shore A 90 material to increase the binding's stiffness.

Putting the Prototypes to the test

The prototype shoes were fully field tested. This "on-snow" functional review proved that the design delivered the targeted characteristics of being lightweight, rugged and functional. After the functional review, Spring Brook released the tooling order for the snowshoe decks. The design information was delivered through IGES files which were exported from SolidWorks and transmitted to the injection molder. The IGES files were used to design the tooling and generate the cutter paths. The first injection-molded decks were delivered within six weeks.

There was one positive surprise when the the first decks were reviewed: the chevron pattern of the traction ribs was highly visible through the translucent Lexan. According to Spring Brook, the dark, shadow-like appearance of the ribs accentuated the modern, high-tech look it had wanted to achieve anyway.

Rapid prototyping played a critical role in the design of the Saguache snowshoe, said Todd Grimm, director of marketing for ATI. "Without this technology, the development process and market introduction would have been delayed by six to 12 months."

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