11/1/2008 | 3 MINUTE READ

Silicone Sleeve Grain Embossing

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Forget about cutting steel embossing rollers. Germany's Benecke-Kaliko has replaced them with laser-cut silicone sleeves that impart greater depth and definition.


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It looks like something you would see in a candy factory: a slow-spinning, laser-scribed "mother" roller receiving a colorful coating. Only it's not a candy factory, and the colorful coating-a self-leveling proprietary silicone mixture-is an inedible dull orange. Once the silicone set, the sleeve is carefully removed from the roller to reveal a three-dimensional negative of the grain found on interior soft-trim surfaces on its underside. It is then shipped to one of Benecke-Kaliko's (Hanover, Germany; www.benecke-kaliko.de) manufacturing plants, where it is placed over a production roller-grain side up this time-and put to work embossing the grain into foils (the surface you see and feel) made of TPO, PVC, or polyurethane.

"We still make steel embossing rollers for some applications," says Dirk Mathjis, Benecke-Kaliko's program manager, North America, Automotive Interiors, "but this technology is far superior in that it allows us to do things that are not possible with steel rollers." Those things include producing grains with a tolerance of 10-15 microns, the ability to place multiple grains on a single roller for comparison purposes, offering a quick turnaround time (about four weeks on a crash program, though more time is better), and easy replication should the surface of the silicone become damaged or wear. "The silicone offers greater control over the three-dimensional volume of the grain," says Günter Vogt, Benecke-Kaliko's senior designer, Automotive Surface Design and Slush, "which gives it the visual depth OEMs are looking for, as well as the ability to create unique grains with a multi-dimensional look." Vogt says the ability to precisely layer the surface of the roller creates unique graphics and special effects that can be highlighted by the use of contrasting lacquers. "It's possible to create a subtle metallic effect by washing the surface with solid color and silver lacquers that highlight the peaks and valleys," he says. The Fiat Group is one of the first to utilize this process to differentiate different models within a vehicle family, and its Alfa Romeo division is combining solid-color lacquer with 3D graining on its new MiTo small car.

"We assign a designer to work directly with each OEM," says Vogt, "so there is no chance of one company's design ending up in the hands of another. However, the technical information is held in common so that no one lags behind." Though the process starts with a sketch, work quickly proceeds to the creation of a prototype grain that is 3D scanned and digitized. A representative patch is made from this information and modified as necessary to get the depth and volume desired for the surface in the computer, and analyze how it will replicate on different foils and under different production methods," he says. So, for example, a grain used on a vacuum-formed piece might be 70% actual grain size to compensate for the stretching that occurs in forming.

Driving the growth of the silicone roller technology, says Vogt, are customers moving from larger to smaller vehicles, "who do not want to give up the look and feel of the vehicles they are leaving behind. Also, every time there is a crisis in the auto industry," he says, "the customer becomes more individual in his tastes." Nowhere is this more evident, he believes, than in the NAFTA region where Benecke-Kaliko is adding this technology to its recently opened plant in San Luis Potosi, Mexico, near the GM plant that will build the next-generation Saturn Astra. Says company CEO Dr. Dirk Leiss, "The desire to produce multiple grains and effects for common platforms provides a significant growth opportunity for us." Especially, he believes, when companies like Ford have outlined a refresh strategy that calls for significant changes to both the interior and exterior every three years.