Option C: CAD/CAM C4 – RAPID PROTOTYPE MANUFACTURE Wet Rapid Prototyping. A technique that uses a fluid support structure that can be washed and drained away. Stereo Lithography. Stereo lithography (SLA) is a 3D printing process that uses a vat of photosensitive resin and a vertically moving platform. It uses a laser beam, directed onto the surface of the photosensitive resin, to print the pattern of the current model layer by hardening the photosensitive resin. The platform then moves down by a layer thickness so the next layer can be printed. Dry rapid prototyping. A technique that uses break-away supports. Laminated Object Manufacture (LOM). LOM machines take the sliced CAD data from the 3D model and cut out each layer from a roll of material, using a laser or plotter cutter. These sliced layers are glued together to form the model, which is either built on a movable platform below the machine or on pins when using card. Solid Object Printing. Solid object printing, in particular wax modelling, employs inkjet deposition technology. A linear array of nozzles deposits molten wax on a platform, layer by layer, to build up the 3D model. Fuse Deposition Modelling (FDM). An FDM machine is basically a CNC robot that holds a small extrusion head. The extrusion head moves back and forth along a platform, building up a 3D model by feeding heated plastic wire through the extrusion head. Select Laser Sintering (SLS). SLS is a 3D printing process based on sintering. A CO2 laser is used to sinter a thin layer of heat- fusible powder that gradually builds up the 3D model. Compare wet and dry rapid prototype techniques. Wet techniques can be used for more intricate internal construction where it would be difficult to break away supports. Dry techniques use a breakaway structure, which can be difficult to remove from detailed areas. Benefits of being able to rapid prototype a product instead of using other CAM techniques. Consider… Product design Speed Time Costs Accuracy Waste. Limitations of rapid prototyping for volume-produced products. Consider the internal structure of a product, and number of components. Rapid prototyping (RP) benefits trials, testing and final part manufacture Consider reduced development time and costs, and user trials. Compare SLS, LOM and FDM rapid prototype processes. Consider… Speed Time Costs Accuracy Surface finish. Describe different design contexts where SLS, LOM and FDM would be applicable. Consider… Quality Cost Accuracy of outcome.