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.

Up to the Customers

While Polaris has been pleased with the cost and look of the cast frame, its customers ultimately will decide the fate of the Core concept bike and future cast frame applications. In the past, Polaris had received criticism from customers who did not like the look of the plastic tanks on the company’s cruiser models. Polaris’ industrial design team was curious to see if the public would accept a bike with a raw cast surface finish.

So far, the bike has scored high on customer interest, gaining attention at various shows, as well as via the Polaris website. Brew said that the first four days the Core concept bike was introduced on the website, traffic doubled. The company has received a large international response, as well.

After the round of shows, the development team will work with Craft Pattern to finalize the fuel system for the bike, which is the last thing to develop before the bike is operational. From there, Brew said it is hard to say whether Polaris will put the whole bike in production or take elements from it and incorporate them into other series.

“No matter what, it is a preview of what we could be doing with future bikes,” Brew said.MC