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Rapid Prototyping & Manufacturing TechnologiesSupport structure can be removed manually or, when water soluble supports areemployed, they can be simply dissolved by put into particular chemical solution.However, soluble support is only available for building ABS model, other high meltingpoint plastic material such as polycarbonate (PC) and polysulphone (PPSF) are notapplicable.2.2.2 FDM materialThe build material is usually supplied in filament form with 1.8mm diameter, but thelayer thickness and vertical dimensional accuracy is determined by the extrusionnozzle diameter and the rate of feeding of the building material, which ranges from0.018 to 0.008 inches. In the X-Y plane, 0.001 inch resolution is achievable.Thermoplastic material is most often used which including Acrylonitrate ButadieneStyrene (ABS), Polycarbonate (PC), polysulphone (PPSF), and investment casting wax isdesigned for investment cast.ABSi ABS-M30* PC-ABS PC* ULTEM9085PPSF*Appearance Ivory White TanTensile Strength(MPa)Tensile Modulus(MPa)FlexuralStrength (MPa)FlexuralModulus (MPa)Notched IzodImpact (J/m)Heat deflection( o C)38 36 34.8 52 72 551993 2413 1827 2000 2220 206859 61 50 97 115 1101797 2317 1863 2137 2507 2206139 123 53.39 106 5995 96 326 127 153 189Density g/cm 2 ) 1.09 1.04 110 1.2 1.34 1.28Elongation atBreak (%)SupportStructure>10 4 1.2 3 4 3Soluble Soluble Soluble Bass Bass Bass*Material Available in ICPage 12IC Professional Training
Rapid Prototyping & Manufacturing Technologies2.2.3 Support StructureSupports in the form of solid type or box type are usually required for the Solid-basedRP system. Box type support is used in FDM. The support material used for FDMdepending on the type of model mater used for making the prototype and can beclassified into two main type – soluble support and break away support. The solublesupport uses a "water-soluble" material which turns into liquid in an ultrasonicheating tank filled with hot (70 degree F) amino based water solution for 4 hours, thesupport is then dissolved in the tank. However the soluble support is only suitable forABS grade model material as shown in the table above. Break away support is usedfor model material which melts at a higher temperature than ABS. Break away supportneed to be removed by hand tools upon the completion of the building of theprototype.The self support angle of FDM is 45 degree and 4 types of support styles are availablefor the creation of support namely Basic support, Sparse support, Surround supportand Break away support. The support curves can be created after the appropriatesupports style is determined.Basic supports will create supports under all part features that are exposed to air onthe underside. The top layer of each support column will have a solid fill and thelayers underneath will have a small air gap between toolpath passes. These passes arecalled the support raster curves. This type support is particular suitable for modelwith fine details in the down face however the build time is long and the moresupport material is used compared with the Sparse support.Sparse supports will create supports that use less material than basic supports. This isaccomplished by creating a new raster fill pattern that has a much larger air gapbetween raster. Like basic supports, the top layer of a support column is built with asolid pattern of raster. The next several layers have the basic raster pattern that has asmall air gap. Progressing downward, a new sparse support region is used below theseveral layers of basic support raster fill. The sparse support regions use a much largerair gap when building the tool path raster. In addition, the region is surrounded by asingle closed tool path-perimeter curve.Surround supports are used to surround small features or parts that require fewactual supports, but cannot stand upright on the platform during the part build.Surround supports will create the support tops just like basic supports but will alsosurround every layer of the model with a minimum thickness of supports.Break-away supports are similar to sparse supports but consist of boxes instead of acontinuous raster. There is no closed toolpath-perimeter curve around the breakawaysupports. They are easier to remove than other support styles for somematerials but build slower than sparse supports. Break-away supports are notrecommended for use with WaterWorks.Page 13IC Professional Training
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Page 5 and 6: 1.1.3 Engineering / Functional prot
Page 7: 1.5 The future market profile of RP
Page 20 and 21: 2.4 Three Dimensional Printing (3DP
Page 26 and 27: 4. Rapid Tool ProductionRapid Proto
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