From the Seas to the Streets

Can a technology developed for one industry have useful application in another?

Can a technology developed for one industry have useful application in another? Tim O'Neill, president and CEO of Advance USA (Old Lyme, CT) thinks so. Speaking of what they call STRATA, O'Neill says, "The process was developed in the mid-'80s as an alternative to spraying fiberglass for building sailboat hulls and decks." The reason behind the development was to have a more process-oriented method, one that was less subjective than the hand spraying of fiberglass. And it was used up through the mid-'90s to produce a series of small sailboats.

According to O'Neill, "We found that by using the technology for sailboats, we were able to reduce the weight of the structure by 30 to 40% compared to fiberglass and to get more structural strength and impact resistance." Given those attributes, it isn't necessarily a far leap to think of one other type of manufacturer of transportation products that is looking for the combination of light weight, strength and impact resistance.

So in the mid-'90s, Advance USA sold off its sailboat-making business and decided to focus on further developing the STRATA technology. And on moving its business to automotive.

Strata process
The STRATA process provides a sandwich-style build combining engineering thermoplastics and glass fibers. Decoma International of America and Advance USA have signed an exclusive licensing and manufacturing agreement in the auto marketplace whereby Decoma, a tier one supplier, will bring its automotive program management and product design skills and Advance USA will provide STRATA.

The process produces parts that have a sandwich-like structure. There are thermoformed plastic, fiber reinforcement, and foamed urethane combined into one piece. Which means that there are processing steps including thermoforming, reinforced fiber pre-forming, and liquid molding. The parts that can be fabricated are on the large side: between 25-ft2 and 250-ft2. They are able to achieve good surfaces, in terms of both smoothness and color. The parts, says O'Neill, are durable.

Among the application areas that he thinks the process can be used for include exterior body panels of a wide assortment: vehicle hard tops, hard tonneaus, recreational vehicle and heavy truck sidewalls, and the like.

O'Neill admits that there is entrenched competition from other processes and materials. "From our perspective," he says, "the technology that is in the most significant competitive situation is SMC [sheet molding compound]." Yet he claims, "We're lighter and more durable."

The process is performed in a series of steps. First up is the thermoforming of an engineering thermoplastic. There are two pieces formed: an outer (which may have been co extruded for purposes of attaining specific aesthetic properties) and an inner sheet. Next, there is the fabrication of inner, reinforcement layers: "Typically, it's e-glass, continuous fiber, not short or chopped," O'Neill says. The fibers are oriented in the direction of the load path, thereby enhancing the strength of the structure. "For a tonneau," O'Neill notes, "you may need significant structure in the cross-vehicle direction." The orientation of the fiberglass is the answer to achieving this necessary structure. The reinforcement layers are attached to the inside surfaces of the thermoplastic skins. Then the skins are moved to a matched die mold that is configured so that there is a cavity between the inner surfaces of the two skins. A polyurethane resin is injected into the cavity. This resin foams, expands to fill the core. According to O'Neill, the engineers at Advance USA have been able to use the foaming urethane not only to provide a core structure between the two sheets, but to actually wet out the glass fibers to bond them together in a matrix. (The foam, incidentally, contributes a sound-deadening effect to the component, which is beneficial with regard to NVH.)

In terms of production volumes, O'Neill says that they are looking at volumes as low as 5,000 to 10,000 units to as many as 100,000 to 150,000 units. According to O'Neill, the tooling required for the STRATA process is less costly than that required to make SMC or steel parts, yet he cautions, "We are not going to replace steel and SMC by any means across the board, but on big parts, where there are issues of structure, durability, and light weight, we are quite competitive."

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