![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](https://image.slidesharecdn.com/mae1659-221119210831-a1ab3ea3/85/MAE1659-ppt-3-320.jpg)
MAE1659.ppt
- 1. Advanced Manufacturing Choices MAE 156-256 Spring 2012, Dr. Marc Madou Class 9: Rapid Prototyping By Dr. Marc Madou
- 2. Two Ways for Fabrication: Subtractive manufacturing Additive Manufacturing
- 3. 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
- 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 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).
- 6. Materials For Rapid Prototyping • Materials covered: – Thermoplastics (FDM, SLS) – Thermosets (SLA) – Powder based composites (3D printing) – Metals (EBM, SLS) – Sealant tapes (LOM) Stereolitography (SLA) Selective Laser Sintering (SLS) Fused Deposition Modeling (FDM) Laminated Object Modeling (LOM) 3D Printing Electron Beam Melting (EBM)
- 7. Examples of Rapid Prototyping Applications: • Prototyping (90 %) – Concept models – Architectural models – Disney characters – Movies—or 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 ?
- 8. Rapid Prototyping by Industry Sectors:
- 9. Methods for RP • Stereolitography (SLA) • Selective Laser Sintering (SLS) • Fused Deposition Modeling (FDM) • Laminated Object Modeling (LOM) • 3D Printing • Electron Beam Melting (EBM)
- 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 casting – LOM, 3D Printing, marketing and concept protos.
- 11. Rapid Prototyping Techniques: Machine Cost Response Time Material Application Fused Deposition Modeler 1600 (FDM) $10/hr 2 weeks ABS or Casting Wax Strong Parts Casting Patterns Laminated Object Manufacturing (LOM) $18/hr 1 week Paper (wood- like) Larger Parts Concept Models Sanders Model Maker 2 (Jet) $3.30/hr 5 weeks Wax Casting Pattern Selective Laser Sintering 2000 (SLS) $44/hr 1 week Polycarbonat e TrueForm SandForm light: 100%; margin: 0">Casting Patterns Concept Models Stereolithography 250 (SLA) $33/hr 2 weeks Epoxy Resin (Translucent) Thin walls Durable Models Z402 3-D Modeller (Jet) $27.50/hr 1 week Starch/Wax Concept Models
- 12. 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)
- 13. LOM Objects
- 14. 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
- 15. FDM Abbreviation: FDM Material type: Solid (Filaments) Materials: Thermoplastics such as ABS, Polycarbonate, and Polyphenylsulfone; Elastomers Max part size (LxWxH): 36.00 x 24.00 x 36.00 in. Min feature size: 0.005 in. Min layer thickness: 0.0050 in. Accuracy: 0.0050 in. Surface finish: Rough Build speed: Slow
- 16. Most common FDM Systems • High Res: – Dimension ELITE • Large FootPrint (12x12) – Dimension SST1200 • Low cost – uPrint ($14,900) • Do it Yourself: – FAB@Home – RepRap
- 17. Stereolitography (SLA) • Patented in 1986 • 3D 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
- 19. 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 0.004” or less
- 20. SLS samples
- 21. 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
- 22. 3D Printing
- 23. 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
- 24. Examples of EBM
- 25. Do it Yourself FDM rapid prototyping (cost under $5K) • FAB@Home • 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.
- 27. Questions and Answers ?
- 28. 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