Case Study: Impossible Deadline? …No Problem

Case Study:
Impossible Deadline? …No Problem

Once a tire’s tread is gone, the safety of your family and everyone else on the road is at risk. What if there was a tire that could grip a wet road just as well when it’s worn as when it’s new? Michelin developed such a tire and it was Harding Display Corp’s job to get sample parts of the new tire for store displays. The sample of the tire needed to show customers how the channels in the tires could convey water from a new tire as well as once it has become worn.


If At First Your Vender Bolts…Try A Better Vendor

Harding Display Corp took on this job as they would any other, but little did they know that the crucial part of their tire display, the tire sample part, was going to be highly difficult to produce. By mid-December, Harding was in panic mode. Their original injection molding vendor delayed the project many times, then finally gave up on the project. Harding made an emergency call to ICOMold for help.

Brian Bay, Senior Project Manager at ICOMold, recalls, “Harding came to us with a picture of a photorealistic computer rendering and a 3D model which was no longer a CAD model after being converted from a Catia model— and it was corrupted. It was like a thousand lines in space oriented to look like a tire. By this time, the original model couldn’t be accessed due to the holiday shutdowns. So, we had one of our engineers recreate the CAD model. However, the photorealistic picture showed a paper-thin blue wall representing water on the inside of the tread channel in the side of the tread. Since this paper-thin substrate can’t be molded due to it being too thin, the customer agreed to eliminate the blue substrate for the first 200 samples and the blue surface would be painted on.”

Because of the part’s curves and the many undercuts on the arch-like piece, a 5-axis CNC milling machine was used for making the mold. The substrate was supposed to be blue originally, but because the sidewall of the tread couldn’t be made paper-thin, we made the substrate and the tire T.P.E. (thermoplastic elastomer) both black. The only option was then to paint the sides of the channels. So, we attempted to paint the sides of the T.P.E. in the tread channel, but the results were less than desirable, to say the least. The remaining unpainted samples were shipped to Harding which, incredibly, met their deadline. Then Harding attempted to paint the water simulation onto the part, but had similar results.

Overmolding

Ed Power, Director of Business Development at Harding, saw the samples they had received and sent us an e-mail – “We have the pieces in hand and they are fantastic!!! WAY beyond my expectations. We still have to paint but we are off to a great start.”

So, Harding wanted 12,000 pieces of the tire display. Because of the complexity and detail of the part, one defect on a feature and the part would be scrap. In fact, the anticipated scrap rate would be 2 out of 3 pieces! We were obviously reluctant to quote considering that this would make the cost per piece shoot up. The cost per piece was too high for Harding – it would destroy their already bruised budget.

Harding then agreed to our redesign to make the substrate blue again, to show the where the water would move through the tire’s treads. This was far closer to the Harding’s desired effect, so they then abandoned the paper-thin water idea. We agreed, at great risk, to lower their price by 1/3 assuming they could improve the processing and reduce scrap to break even or possibly better. Once main production began, we were making two large shipments per week. Harding was surprised, and very pleased, that our new design improved the process so much that all the parts were shipped about two weeks prior to the anticipated completion date.