Presentation on theme: "Advanced Manufacturing Choices MAE 156-256 Spring 2012, Dr. Marc Madou Class 9: Rapid Prototyping By Dr. Marc Madou."— Presentation transcript:
Advanced Manufacturing Choices MAE Spring 2012, Dr. Marc Madou Class 9: Rapid Prototyping By Dr. Marc Madou
Two Ways for Fabrication: Subtractive manufacturing Additive Manufacturing
Rapid Prototyping Some other names: –Additive manufacturing –Computer controlled moldless additive manufacturing Part is produced by producing multiple slices i.e. cross sections From 3D model [STL file (see next slide)] to physical object, with a click –Layered manufacturing –Rapid prototyping: Variety of methods: more and more functional products rather than just prototypes
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.
Basic Principles of Rapid Prototyping Rapid Prototyping 3d model generated Sliced Each slice manufactured and layers are fused together A 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).
Examples of Rapid Prototyping Applications: Prototyping (90 %) –Concept models –Architectural models –Disney characters –Moviesor is that real and thus manufactured? –Etc Manufacturing (10%) –Implants and custom medical devices –Aerospace parts –Pilot scale production of lab equipment –Molds.. A Stradivarius ?
Rapid Prototyping by Industry Sectors:
Methods for RP Stereolitography (SLA) Selective Laser Sintering (SLS) Fused Deposition Modeling (FDM) Laminated Object Modeling (LOM) 3D Printing Electron Beam Melting (EBM)
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 casting –LOM, 3D Printing, marketing and concept protos.
Process: Laminated Object Modeling (LOM) Object made by deposition and cutting of layers of tapes Introduced in 1991 by Helisys Inc of Torrance. Cubic and Helisys offer this technology Slow, sharp edges Research on composites prepregnated moldless manufacturing Inexpensive depending on accuracy, large scale models possible Slow and inaccurate (knives vs lasers)
Fused Deposition Modeling (FDM) Extruder on a cartesian robot Extrudes thermoplast polymers spaghetti Moderately fast and inexpensive Stratasys is the market leader Functional parts, ABS and nylon Best choice for mechanical engineers and product developers ! Can be used for direct digital manufacturing Systems starting from $14,000
FDM Abbreviation:FDM Material type:Solid (Filaments) Materials:Thermoplastics such as ABS, Polycarbonate, and Polyphenylsulfone; Elastomers Max part size (LxWxH): x x in. Min feature size: in. Min layer thickness: in. Accuracy: in. Surface finish:Rough Build speed:Slow
Most common FDM Systems High Res: –Dimension ELITE Large FootPrint (12x12) –Dimension SST1200 Low cost – uPrint ($14,900) Do it Yourself: –RepRap
Stereolitography (SLA) Patented in D System is the market leader Highest resolution and smoothness UV Laser beam cure cross-sections of parts in a liquid batch of photoreactive resin Subvariants: DLP entire layer projection
Selective Laser Sintering (SLS) Can be used for both thermoplastics and metal Powder is fed into a continuous layer Laser is used to fuse/sinter powder particles layer-by-layer Produces functional parts Layer thickness or less
3D Printing Layer of powder is first spread across build area Inkjet-like printing of binder over the part cross-section Repetition of the process with the next layer Can produce multi-colored parts Useful only for presentation media Lowest resolution of all techniques Market Leader: Z-Corp
Electron Beam Melting (EBM) Dispensed metal powder in layers Cross-section molten in a high vacuum with a focused electron beam Process repeated until part is completed Stainless steel, Titanium, Tungsten parts Ideal for medical implants and injection molds Still very expensive process
Examples of EBM
Do it Yourself FDM rapid prototyping (cost under $5K)
The Future ? Self-replication ! RepRapRepRap 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.Make RepRap Darwin Obtaining Parts link
Questions and Answers ?
Rapid Prototyping Process Flow Solid Modelling Tesselation/Generation of STL file Support Generation Slicing of the Model Model Physical Buildup Cleanup and Post Curing Surface Finishing