Presentation on theme: "Advanced Manufacturing Choices"— Presentation transcript:
1 Advanced Manufacturing Choices MAESpring 2012, Dr. Marc MadouClass 9: Rapid PrototypingBy Dr. Marc Madou
2 Two Ways for Fabrication: Additive ManufacturingSubtractive manufacturing
3 Rapid Prototyping Some other names: Additive manufacturing Computer controlled moldless additive manufacturingPart is produced by producing multiple “slices” i.e. cross sectionsFrom 3D model [STL file (see next slide)] to physical object, with a “click”Layered manufacturingRapid prototyping:Variety of methods: more and more functional products rather than just prototypes
4 STL File*The STL (stereo lithography) file format is supported by many other software packages; it is widely used for rapid prototyping and computer-aided manufacturing (CAM). STL files describe only the surface geometry of a three dimensional object without any representation of color, texture or other common CAD model attributes.*An STL file describes a raw unstructured triangulated surface by the unit normal and vertices (ordered by the right-hand rule) of the triangles using a three-dimensional Cartesian coordinate system.
5 Basic Principles of Rapid Prototyping 3d model generatedSlicedEach slice manufactured and layers are fused togetherA voxel (volumetric pixel or, more correctly, Volumetric Picture Element) is a volume element, representing a value on a regular grid in three dimensional space. This is analogous to a pixel, which represents 2D image data in a bitmap (which is sometimes referred to as a pixmap).
7 Examples of Rapid Prototyping Applications: Concept modelsArchitectural modelsDisney charactersMovies—or is that real and thus manufactured?EtcManufacturing (10%)Implants and custom medical devicesAerospace partsPilot scale production of lab equipmentMolds .. A Stradivarius ?
10 Selection of Optimal Process Functional parts:FDM (ABS and nylon)SLS (thermoplastics, metals)EBM (high strength alloys, Ti, stainless steel, CoCr)Non functional parts:SLA: smoothest surface, good for castingLOM, 3D Printing, marketing and concept protos.
12 Process: Laminated Object Modeling (LOM) Object made by deposition and cutting of layers of tapesIntroduced in 1991 by Helisys Inc of Torrance.Cubic and Helisys offer this technologySlow, sharp edgesResearch on composites prepregnated moldless manufacturingInexpensive depending on accuracy, large scale models possibleSlow and inaccurate (knives vs lasers)
14 Fused Deposition Modeling (FDM) Extruder on a cartesian robotExtrudes thermoplast polymers “spaghetti”Moderately fast and inexpensiveStratasys is the market leaderFunctional parts, ABS and nylonBest choice for mechanical engineers and product developers !Can be used for direct digital manufacturingSystems starting from $14,000
15 FDM Abbreviation: FDM Material type: Solid (Filaments) Materials: Thermoplastics such as ABS, Polycarbonate, and Polyphenylsulfone; ElastomersMax part size (LxWxH):36.00 x x in.Min feature size:0.005 in.Min layer thickness:in.Accuracy:Surface finish:RoughBuild speed:Slow
16 Most common FDM Systems High Res:Dimension ELITELarge FootPrint (12x12)Dimension SST1200Low costuPrint ($14,900)Do it Yourself:RepRap
17 Stereolitography (SLA) Patented in 19863D System is the market leaderHighest resolution and smoothnessUV Laser beam cure cross-sections of parts in a liquid batch of photoreactive resinSubvariants: DLP entire layer projection
19 Selective Laser Sintering (SLS) Can be used for both thermoplastics and metalPowder is fed into a continuous layerLaser is used to fuse/sinter powder particles layer-by-layerProduces functional partsLayer thickness 0.004” or less
21 3D Printing Layer of powder is first spread across build area Inkjet-like printing of binder over the part cross-sectionRepetition of the process with the next layerCan produce multi-colored partsUseful only for presentation mediaLowest resolution of all techniquesMarket Leader: Z-Corp
23 Electron Beam Melting (EBM) Dispensed metal powder in layersCross-section molten in a high vacuum with a focused electron beamProcess repeated until part is completedStainless steel, Titanium, Tungsten partsIdeal for medical implants and injection moldsStill very expensive process
25 Do it Yourself FDM rapid prototyping (cost under $5K) RepRap
26 The Future ? Self-replication ! RepRap achieved self-replication at 14:00 hours UTC on 29 May 2008 at Bath University in the UK. The machine that did it - RepRap Version 1.0 “Darwin” - can be built now - see the Make RepRap Darwin link there or on the left, and for ways to get the bits and pieces you need, see the Obtaining Parts link.