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Tooling venTure MulTi-size capabiliTy Several years before the 360Rush project, SplashTacular and JRL had conferred about the possibility of using a modifed closed cavity bag molding (CCBM) process that employed partial molds in slide sections. Partial molds are designed with moveable fanges or blockers that can be repositioned, enabling the company to make parts of more than one size from a single mold. JRL had experience producing some frst-article parts with CCBM, which uses a rigid A-side mold and a silicone or elastomeric bag on the B side, but had not tried it with a partial-mold confguration. "One of the problems in the past when we tried to use a closed molding process, such as light RTM, is that we had to build a full mold for every part, which gets expensive," says Jeremy Wilson, senior project engineer at SplashTacular. "We just felt there had to be a way to make this happen." Wilson credits JRL with make partial molds compatible with the CCBM process by developing a way to use a single reusable bag with a partial mold to produce parts with diferent lengths. One of the partial molds, for example, makes slide fume sections that are 90, 42, and 37.5 inches (2,286, 1,067 and 953 mm) long. Te length of the bag is dictated by the longest part. Te blocker is moved to shorten the part length. Te challenge, then, was to get the bag to seal and hold a vacuum around the blocker and conform to the blocker's shape. "We had to experiment," says Kevin Long, project manager at JRL, who reports that they "found a way to make the blocker without any sharp angles or bends so when you pull a vac- Silicone bags for the project were made directly off the tool, rather than from wax inserts or a hand-layed model. The technique worked well with slide molds because the parts have large and open shapes and are made Source | SplashTacular with identical ply schedules. uum and begin to infuse that section, the bag pulls down and seals without inficting damage." Te rubber seal around the fange of the entire bag holds the vacuum in that section, and the inherent elasticity of the silicone conforms to the shape of the blocker. Ultimately, the experiment yielded signifcant savings in tooling cost. Te slide's 134 parts were produced with 12 full molds and three partial molds. Notably, the three partial molds, which formed sections of the slide's fumes, accounted for more than half of the total parts. Afer the fnal design was approved and the partners were satisfed that their new tooling strategy was viable, tool build was initiated with the manufacture of plugs. CAD data was imported into a 5-axis CNC machine for cutting plug components, the majority of which were rough cut, with an undercut shape, out of low-density expanded polystyrene supplied by Carpenter Co. (Richmond, Va.). Te plugs were sealed with a proprietary resin and coated with ITW SprayCore's (Clearwater, Fla.) SprayCore 4500, a sprayable, syntactic vinyl ester. Te cured syntactic ofers a hardened layer of material that, Long says, exhibits low shrinkage and is easy to machine. Afer the plugs were milled, their surfaces were dry- and wet-sanded to a 400-grit fnish. Fiberglass toolmaker JRL Ventures (Cape Coral, Fla.) developed a method of using a single reusable bag with a partial mold (below) to produce parts of different lengths by means of a moveable fange or blocker (colored black). This partial mold can produce slide fume sections that are 90 inches, 42 inches and 37.5 inches in length. Source | SplashTacular CT oCTober 2013 JRL is a subsidiary of Cape Coral-based Marine Concepts. Engineering director Kevin Long says the company has been seeking to grow its share of business in the amusement park market over the past fve years. Afer attending shows, such as the International Association of Amusement Parks and Attractions (IAAPA) in Orlando, Fla., Long says the company realized it couldn't compete in molds for small, intricate parts made primarily in Asia. It did, however, perceive an opportunity in the water park segment, which usually entails the production of much larger parts. SplashTacular's 360Rush represented JRL's frst signifcant multimold contract in this market. JRL primarily used NX CAD sofware, supplied by Siemens PLM Sofware (Plano, Texas), to fnalize the slide design, surface part sections and fair section mating surfaces and edges. Finite element analysis (FEA) was performed on CAD models of the complete slide as part of the design process. SplashTacular used NASTRAN FEA sofware to conduct and analyze a ride simulation of two people descending through the slide and into the bowl. Te main program inputs were the heights, weights and proportions of the riders. SplashTacular engineers evaluated the simulation to verify that the linear motion of each rider stayed at or below a threshold speed at specifc locations on the slide. Rider speed and location within the fumes were assessed to ensure there is no chance two riders will collide as they enter the bowl. Te contribution of slide design to any anomalies in rider mechanics during the simulation was assessed by SplashTacular engineers, resulting in further modifcation of the CAD model. Additional NASTRAN simulations and iterations continued until an acceptable design was achieved. 37