Perfect and On-Time

As a manufacturer of prototype metal and plastic components, Craft Pattern and Mold is geared toward working on complex parts with tight deadlines, and the Polaris Core concept bike was no exception.

The industrial design team at Polaris handed over the order for the frame component, as well as 8-10 other castings and machined parts needed for the concept two-wheeler, shortly after Thanksgiving ’08. The deadline: before Christmas. Polaris planned on showing the bike at several shows throughout 2009, starting with one held mid-January. The bike required a week of assembly and photography for the launch and another week for delivery to the show.

“Those guys [at Craft Pattern and Mold] were fantastic,” Brew said. “It wouldn’t have happened if they just acted like a supplier. But they were more like a partner. It’s pretty staggering how quickly they turned it around.”

Tony Cremers, president of Craft Pattern and Mold, estimates his team spent three days engineering the casting and tooling before CNC cutting the patterns and coreboxes for the nobake sand molding process. Tool development took about a week, and the castings were poured the next day.

One of the biggest challenges in engineering the tooling and casting design was determining where to locate the cores and hold them in place without inducing casting defects.

“There weren’t many exit holes in the casting,” Cremers said. “So we incorporated chaplets to keep the wall thickness of the interior walls accurate.”

Craft Pattern and Mold’s engineering and tooling professionals worked with Polaris staff on developing a design that offered the best opportunity for success considering the accelerated timeline. Adding material to thin wall sections between core cavities and the addition of internal chaplet markers were readily accepted by Polaris engineering and incorporated into the design.

Because Craft Pattern and Mold was producing several other prototype parts for the Core motorcycle, first-pour casting success was critical to the project moving forward without delays due to part redesign and tool revisions.

“The backbone casting was the hinge of the whole project, so when it was poured 100% correct the first time, it was a relief,” said Steve Shade, Craft Pattern project manager.

Craft Pattern produced two prototype units, which were heat treated to a T6 condition and machined, before delivering the parts to Polaris on time and ready for assembly. The castings fit up with the other mating components flawlessly the first time.