How is 3DL Made?

© Guy Gurney 1) A 3DL^® sails begins with a three dimensional CAD/CAE design file created by a North Sails sail designer. North's proprietary design software creates a custom "mold" file for each individual sail. Because a 3DL sail stretches less than competing 2D paneled or “string” sail for a given amount of yarn, North designers can more accurately define the desired "flying shape" because the computer molded shape is that much closer to the resultant flying shape.
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© North Sails 2) A sophisticated computer program reads the design file, then instructs an articulating mold to assume the designed shape. Shown here is the underside of a 3DL mold with actuators controlled by a highly sophisticated computer program.
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© North Sails 3) After a base layer of Mylar film (made from Mylar sections joined together with modest shaping to lie reasonably smoothly over the 3D surface of the mold) is draped over the mold and tensioned, a 6-axis fiber head suspended from a computer controlled overhead gantry then applies structural yarn onto the surface of the base film, precisely following the 3D curve of the mold surface. The fiber head "draws" a pattern in yarn that matches anticipated loads in the sail. All structural yarns are applied under uniform tension and adhere to the surface of the film to ensure they remain in place prior to being locked by the lamination.
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© North Sails 4) Once the yarns are laid, a second film is positioned on top of the base film and yarn, tensioned, and then covered with a large vacuum bag that compresses the laminate at approximately 1,800 pounds per square foot. This second film contains a secondary mapping of yarns to handle incidental loads off the primary load lines.
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© North Sails 5) The gantry head is then removed and replaced with a carbon element heat “blanket” that cures the pressurized laminate by imparting a carefully controlled amount of heat through the laminate. This causes the laminate to conform tightly to the mold in a manner similar to a shrink-wrapping process. After curing, the sail is allowed to cure further for a full five days prior to shipping and/or finishing.
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© North Sails 6) When the laminate has cured, corner reinforcements, bolt ropes, batten pockets and protective patches are applied by experienced sailmakers. Because of the inherent material efficiency of the 3DL manufacturing process, a finished 3DL sail can be up to 20% lighter than a conventional paneled or a “string” sail of equivalent stretch. Or, it has a wider wind range (larger sweet spot) for a given weight.