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Issue link: https://ct.epubxp.com/i/178128
INSIDE MANUFACTURING 2 Technicians initiate part production by pulling a vacuum of 23 to 28 psi on the bag. 3 The mold is infused with an ISO dicyclopentadiene resin that contains a blended catalyst. The resin enters through two ports at the top of the bag. 4 Filling the mold usually takes 12 to 15 minutes, depending on the size of the part. 5 Once the mold is flled, injection lines are clamped to maintain the vacuum and the curing process begins. The cured part is allowed to cool on the mold. 6 The part is pulled from the mold, and its backside is ready for gel coat. Source (all step photos) | SplashTacular 1 After application of the gel coat, a single layer of 18-oz woven roving is layed up on the mold and the silicone bag is positioned and secured over the cavity and fange. hold a vacuum during infusion. An added challenge to the tool design-and-build phase of the project — for partial, split and standard molds — was the complex three-axis part curvature along the length of most slide sections. Tis complicated the tool design and build, as well as part connectivity. "Te bolt line is not simply a vertical fange," Long points out, "so we had to take care during CAD modeling to ensure all the parts mated 90° to the mating surface." Multi-use capability For the vacuum bags, SplashTacular and JRL used sprayable grades of silicone supplied by a number of companies. Approximately 0.125 inch/3.18 mm thick, the silicone bags are more expensive than traditional disposable bag materials, but their upfront cost is mitigated by the fact that they are reusable. JRL further reduced the perpart bag cost on the 360Rush project by pulling the bags directly of the tools, rather than from wax inserts or a hand-layed model. Although this technique is not always advisable, it worked well with the slide molds because the parts have large and open shapes and are made with an identical ply schedule. "In a structure with cores you would not want to build the bag of the mold because you'd create wrinkles," he warns. SplashTacular uses in-house resin blending equipment to produce its own gel coats in 180 colors. But because of the blaze, blue and green gel coats (for the inner and outer surfaces of the slide and bowl, respectively) were custom mixed to SplashTacular's speci- CT oCTober 2013 Afer polishing, each plug cavity was prepped with mold release and then coated with Polycryl Corp.'s (Oakland, Tenn.) Diamondback Y-501 orange gel coat. Next, a layer of 1.5-oz glass mat, supplied by Composites One (Arlington Heights, Ill.), was hand layed over the cured gel coat and wet-rolled with Polycryl's Earthguard EG2500 vinyl ester tooling resin. Two additional layers of 1.5-oz mat were laid and wet rolled over a two- to three-day period. Finally, a layer of Earthguard EG3000 high-temperature vinyl ester resin, averaging 0.5-inch/12.7-mm thick, was applied over the glass mat and allowed to cure at ambient temperature to yield molds ranging in thickness from 0.375 inch to 0.75 inch (9.5 mm to 19 mm). Te cured, demolded tool surfaces were wet sanded to a 600-grit fnish and then power bufed using a three-step compounding process. Te blockers for the partial tools were formed by hand laying six consecutive layers of 1.5-oz glass mat, each of which was wet rolled with Earthguard EG2500. Afer the fnished tools were supported with steel framing, they were production ready. One of the unique aspects of manufacturing the slide was the high percentage of split or captive-shape tools. Of the 15 tools produced, 11 were split, including the three partial tools. "Because of the negative draf angles and undercut on many of the slide sections," Long explains, "you couldn't remove the part without removing part of the mold." Te split molds, therefore, typically feature three or four sections contained or cradled in the tool's steel-reinforced frame. Rubber gaskets along the seams of the split sections ensure that the molds 39