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The data interface between CAD software and the machines is the .stl format. An .stl file approximates the shape of a part or assembly dividing into triangulated surfaces or facets using a three-dimensional XYZ. The smaller the facets the higher quality surface in the RP processes RP process materials can produce accurate, relatively stiff - tough parts, including water-resistant, thermal resistance is required. Other material options include flexible materials with shape retention for mechanical snap-fits for locking case and cover applications. Compared to the high costs for tooling investment for injection molding, the Rapid Prototype fabrication service can be faster and less expensive when design, geometry verification and small quantities are required. RP TechnologiesA large number of RP process options with the main differences found in the way the layers are built to create the part. The SLA, & PolyJet are laying liquid resin thermosets that are cured with UV light activated photopolymers. SLS and FDM are melting, softening or fusing material to produce the layers. LOM Laminated Object Manufacturing uses a lamination system, where thin layers are cut to shape and joined together.
SLA Stereolithography SLA uses a focused laser beam over a vat of liquid photo polymer resin. As the laser draws the layer, the photo polymer changes from a liquid to a solid. When the cross-section is solidified, another layer of liquid photopolymer covers the surface of the previous layer and laser solidifies this layer, and so on. When the part is finished, it is removed from the vat and cleaned of its support structures and excess resin. Then it must go through a final post-curing process. There are several resins option available. Maximum sizes: 20"x20"x20". Material choices: Semi-Flexible, PE-Like (Ref: Somos 8110); Durable, PP-Like (Ref: Somos 9420); ABS-Like (Ref: Somos 14120/Accura 50); Rigid, PC-Like (Ref: Somos 11120/Accura 60); High Resolution (ABS-Like, Durable, Rigid); High-Impact ABS-Like (Ref: Somos DMX-SL 100). Tolerances of +/- 0.005" for the first inch, +/- 0.002” on every inch thereafter. Layer Thickness: High-Resolution: 0.002” - 0.004”; Standard Resolution: 0.005” - 0.006”. Finish Options: Standard, Primed, Painted, WaterClear.
SLS - Selective laser sintering Selective laser sintering (SLS) is another focused laser beam technology which draws the cross-section of the part being built on a layer of powder. As the laser draws, the heat of the laser fused the particles of powder together. At the end of the cross-section, another layer of powder is applied to the surface and then it too is drawn and fused, adhering to the layer below. When the part is finished, the unsolidified powder is removed from the part. The SLS process can use several different materials which offer the closest mechanical representation of an injection molded part including glass filled for extra rigidity, strength, heat and & chemically resistant. Currently materials available for functional testing elastomeric, polystyrene, sand form patterns, rapid steel and copper polyamide. Typically SLS parts are not used for appearance quality parts based on the granular surface finish and the finishing work necessary to achieve appearance quality. Materials: Nylon (Duraform PA), Glass-Filled Nylon (Duraform GF), Flame Retardant Nylon, Durable Nylon (Duraform EX), and SLS Flex. Size limitations: are basically 10 x 12 x 16" Accuracy: resolution quality and geometrical dimensional tolerance is ranged at: 0.003" - 0.005" of an inch, considering surface finish texture
FDM - Fused Deposition Modeling FDM Fusion Deposit Modeling excellent for Conceptual Models, Engineering Models, and Functional Testing Prototypes. This process uses an extrusion head to deposit a bead of material on a layer by layer platform contouring to the desired geometry. The most common material is ABS. or a medically approved grade of ABS Also used for investment casting molds. Maximum dimensions for parts in single build: ABS - 23"x19"x23", Polycarbonate (PC) - 14"x16"x16". Materials: ABS (red, yellow, green, blue, white, and black), Polycarbonate (white), & PC-ABS (black), Food-grade ABS material Tolerances are +/- 0.005" for the first inch, and +/- 0.002" Layer Thickness: Standard Resolution: 0.01”; Minimum wall thickness is 0.02”. LOM™ Laminated Object Manufacturing by Helisys Inc. uses layers of adhesive-coated paper are successively glued together and cut to shape with a laser cutter. A very crude mock-up process limited to small sizes
General Questions: Willis Whiteside willis@whitelightdesign.com
PROCESS
Modelmaking - Quick study concept
models (cardboard, Styrofoam, etc.) Breadboard – Crude
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