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26 The Costume Designer Fall 2015 BY CHRISTINE COVER FERRO 3D Printing T hree-dimensional printing, formally known as additive manufacturing, has taken a series of evolutionary leaps in the last few years. The intent of the technology when it was originally developed in the early eighties was to speed up the development of prototypes in industrial product design. Since then, the technology has found its way into just about every discipline, and scientists have developed the capacity to "print" with just about every material imaginable, from metals, to food, to biological tissue, to, quite usefully for Costume Design, fabric. 3D printing has become so prolific and varied that the rep- licators aboard Star Trek's Enterprise and Voyager no longer seem far-fetched. The process begins by creating a virtual design. Designs can be created from scratch using modeling software or by using a 3D scan of an existing object (or person) and modifying as desired. This design is then optimized for printing, adding support to intri- cate geometry as needed and breaking it down into very thin (as in 0.1mm) slices. The printer then builds each of these slices in a sequenced stack, creating the finished object. That 3D printing is being steadily integrated into the Costume Design and fabrication process won't be news to any design team that has recently done any sort of specialty fabrication. Components for comic book heroes and science fiction costumes have been prototyped with 3D printers for the last several years. The proliferation of the technology will only continue to make it more accessible, either in-house or through third parties, even when the project doesn't have a nine-figure budget. There are numerous processes that fall under the 3D printing umbrella. The most commonly encountered are: Extrusion Also known as Fused Deposition Modeling (FDM) and Fused Filament Fabrication (FFF), is probably what most people think of when they think of 3D printing. A thermoplastic filament is fed through a heated extruder that deposits each new layer onto a build plate. For pieces that have overhanging geometry, support structures need to be worked in. With FDM, a second water-soluble filament fills in the gaps until completion and is then washed away. FFF requires that breakaway structures be designed in and are then snapped off upon completion. The process can be slow, and layers may not always completely adhere properly, although this can be remedied with post-processing. The quality of personal-use machines is constantly improving, and the development of new filament materials has exploded in the last few years, allowing users to print in metal or wood composites, as well as more flex- ible plastics. Inkjet Either binder or material jetting, as the name suggests, work much like your home printer. Instead of ink on paper, the printer selectively sprays binder onto a powder bed in the case of binder jetting; and, for the latter, liquid or melted build materials are jetted through multiple heads onto a build plate and cured with UV light as each layer is deposited. Both systems allow for simultaneous use of multiple colors. Stereolithography Also known as SLA, stereolithography uses an ultraviolet laser to project the sequence of cross sections of the finished object onto a vat of liquid ultraviolet light reactive polymer resin. As the laser completes projecting each cross section, curing the surface of the resin, a platform in the vat moves down the distance equiva- lent to the thickness of the layers. The laser then projects the next layer onto the new liquid surface, and the cycle continues until the object is complete. Once the finished object comes out of the vat, a chemical bath cleans off excess resin, and further curing the piece in an ultraviolet oven fully cures the resin. This process is one of the most accurate in the market, but is limited by the resin's instability, as it will often become brittle over time. Selective Laser Sintering SLS, also known as laser melting, uses an ultraviolet laser, but the material on the platform is densely packed powder (plastic, nylon, or metals). The laser fuses the powder it hits, the platform moves down, a roller creates a smooth, new layer and the next layer is fused to itself as well as the previous layer. The process accommodates the most intricate structures without the support structures that would be necessary in other processes. Because the materials used are some of the strongest available within the tech- nology, pieces produced through this method can be functional How It Works