Irving Oil Case Study

Good Design, Closed Moulding Ensures Quality

Eye-catching "icons" or distinctive physical forms that signify a company brand — think Bob's Big Boy, the Midwestern restaurant landmark, for example — lend themselves well to composites because they often involve complex shapes that must look good in tough environmental conditions. FormaShape, a division of WhiteWater Composites Ltd. (Kelowna, British Columbia, Canada), known for construction of water park features, is replacing aluminum in brand icons and related architectural shapes with fiberglass composite materials. The company has already worked with two prominent Canadian petroleum marketing companies, Irving Oil (Saint John, New Brunswick, Canada) and Petro-Canada (Calgary, Alberta, Canada) to help each create new convenience store and gas station canopy designs as part of a rebranding process.

FormaShape's engineering manager Henry Czenczek says that one of the biggest advantages of FRP in branding applications is design flexibility: “You have unlimited forms, shapes and looks available,” he explains. Despite this ability to produce complexly curved forms, Czenczek says that potential customers still need convincing to appreciate the benefits of FRP over other products on the market, such as ACM cladding (thin aluminum sheet on both sides of a flexible thermoplastic core).

The Irving Oil project, FormaShape's “first real engineered project,” according to Czenczek, involved a rigorous design process. “Irving had a prototype site renovated using aluminum material and ended up not liking the look at all,” he says. To help ensure the success of its FRP designs, FormaShape employed a step-by-step project analysis to ensure that FormaShape and Irving Oil were on the same page and that the designs were truly functional. Wind loads on the shaped canopy structures and gas pump shrouds were the primary structural design consideration, dictating part thickness, stiffness and the attachment design, says Czenczek, After extensive customer feedback analysis based on the company's "function analysis system technique (FAST)" diagrams, FormaShape developed shop drawings and product specifications that showed how each of the fiberglass panels would be molded and fitted, and sent them to Irving for approval.

For this project, says Czenczek, Irving wanted the FRP parts — the protective canopy roofs over the fuel pumps, including fascia (canopy trim and brand signage panels) and shrouds attached to the pumps themselves — to have no visible fasteners. To address this, FormaShape initially designed a structural snap-fit solution, using integral aluminum extrusions molded into the parts. However, the customer was concerned that the snap-fit panels would be too difficult to remove during canopy maintenance. As a result, the canopy and fascia were redesigned to be fastened together with pop rivets, painted to match the canopy color, and unnoticeable from ground level, with traditional hinged openings for maintenance. Powder-coated aluminum trim strips, also painted to match, fit over the canopy and fascia edges. The flat "Irving" sign panel with thermoplastic letters is backlit and has a hinge along the bottom, explains Czenczek, to simplify electrical and lighting access. Pump shrouds, at customer eye level, were designed with a fastening system where an end cover plate fits into place over the rest of the assembly, with no rivets.

"The Irving signage has a flat front surface that transitions to a curved shape that is continuous around the four corners of the canopy. The design wouldn't have been possible with existing cored aluminum cladding material," he notes.

To meet the relatively high production rates (nearly 80 gas station sites have been completed to date) and ensure dimensional tolerances, FormaShape manufactures with light RTM — resin transfer molding in closed molds that combines low injection pressure with a vacuum. Because of the low pressure, the process enables use of lightweight FRP tooling to save cost. Czenczek explains that the process is cleaner and faster than hand layup, cuts air emissions, uses less resin, produces Class A surfaces inside and out, and allows molded-in ribs and fasteners: "It's part of our overall lean manufacturing strategy."

Once Irving Oil approved the final part designs, mold construction began with CNC-machined male foam plugs. Economical fiberglass molds were pulled from the plugs, using low-shrink polyester tooling resin supplied by Nord Composites (Conde Folie, France) and fiberglass chopped strand mat (CSM) combined with chopped fiberglass roving. The molds incorporate a layer of polymer concrete in the middle of the laminate, about 0.5-inch/12.7-mm thick, with embedded copper tubing for integral heating. While the polymer concrete adds significant weight, the molds are supported on wheeled carts to ease transport around the shop. Seven different molds were produced for the Irving project.

For part production, which is ongoing, molds are prepped with Frekote mold release, supplied by Henkel Corp. (Madison Heights, Mich.). A single ply of PolyMat reinforcement from Flemings Textiles Ltd. (div. of Scott & Fyffe, Kilmarnock, Ayrshire, U.K.), made with chopped strand mat skins and thermoplastic core that acts as a flow medium, is placed in the mold. Canopy and fascia parts use 450/M5/450 PolyMat while pump shrouds are made with heavier 600/M5/600 mat. Filled AROPOL unsaturated polyester resin from Ashland Performance Materials, Composite Polymers (Dublin, Ohio) is injected into the closed heated molds at a pressure of about 0.5 bar/7 psi, while a vacuum is pulled. Parts are cured at room temperature. The complete cycle takes about two to three hours, and no post-cure is required, notes Czenczek.

The finished products are 20 to 30 percent lighter than competing aluminum designs, and the demolded canopy parts, typically 8 ft/2.4m long and 3 ft/1m high, have integral male/female joints at the ends for joining. Lettered icon panels are attached to a subassembly through routed holes along their perimeter. The entire fascia subassembly is then stiffened with an aluminum frame and attached to the canopy. Parts are painted with an automotive-grade acrylic urethane paint system from BASF Corp. (Florham Park, N.J.), which FormaShape backs with a 10-year no-fade warranty.

Concludes Czenczek, “We've learned a lot working with FRP and our experience has driven us to our present system of a complete design process and efficient manufacturing methods.”

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