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  1. 1. Additive Manufacturing Reshaping Manufacturing: Understanding 3D Printing Processes Prof. Brent Stucker Founder & CEO, 3DSIM, LLC Edward R. Clark Chair of Computer Aided Engineering Department of Industrial Engineering, University of Louisville Inaugural Chairman, ASTM F42 Committee on Additive Manufacturing
  2. 2. Additive Manufacturing AM has the potential to enable anyone to make many things they require, anywhere!
  3. 3. Additive Manufacturing AM enables… …an advanced manufacturing facility to be set up using only electricity, some raw materials, and a computer.
  4. 4. Additive Manufacturing AM enables… …an entrepreneur to start selling a new product without ever needing to buy a machine, purchase a tool or prove out a mold; and start shipping products the day after the design is finalized.
  5. 5. Additive Manufacturing AM is used for the… …automated manufacture of hearing aids so that you simply scan the ear, print out a custom-fitted hearing aid, insert electronics, and ship them by the millions.
  6. 6. Additive Manufacturing What is Additive Manufacturing? (3D Printing) • The process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies
  7. 7. Additive Manufacturing University of Louisville’s Involvement in AM • One of the best equipped additive manufacturing (AM) facilities in the world • Performing Basic and Applied Research, since starting with SLS in 1993 • Over 20 people focused on AM • Close partner of leading AM users – Boeing, GE, DoD, service bureaus, etc. • Over 70 member organizations in our RP Center – Includes Haas Technical Education Center
  8. 8. Additive Manufacturing Typical AM Process Chain 1. Create CAD Solid Model 2. Generate STL File 3. Verify File & Repair 4. Create Build File 1. Orientation, Location 2. Slicing 3. Support Material Generation 5. Build part layer-by- layer 6. Post-processing Click for Movie
  9. 9. Additive Manufacturing What is an STL Model File? • Represents 3D solid models using groups of planar triangles – Describe each triangle by • 3 vertices & unit normal vector – No topological information • Enumerate all triangles • No special order – Better accuracy = smaller triangles = larger files • Set triangle accuracy relative to accuracy of machine used • Holes between triangles, overlapping triangles, and inverted vectors can be problems • No knowledge of dimensions (mm or inches) Facet 1 Facet 2 Facet 3
  10. 10. Additive Manufacturing New Additive Manufacturing File Format • AMF – Additive Manufacturing Format – Additive Manufacturing File
  11. 11. Additive Manufacturing General Concept (XML) • Parts (objects) defined by volumes and materials – Volumes defined by triangular mesh – Materials defined by properties/names • Color properties can be specified – Color – Texture mapping • Materials can be combined – Graded materials – Lattice/Mesostructure • Objects can be combined into constellations – Repeated instances, packing, orientation
  12. 12. <?xml version="1.0" encoding="UTF-8"?> <amf units="mm"> <object id="0"> <mesh> <vertices> <vertex> <coordinates> <x>0</x> <y>1.32</y> <z>3.715</z> </coordinates> </vertex> <vertex> <coordinates> <x>0</x> <y>1.269</y> <z>2.45354</z> </coordinates> </vertex> ... </vertices> <region> <triangle> <v1>0</v1> <v2>1</v2> <v3>3</v3> </triangle> <triangle> <v1>1</v1> <v2>0</v2> <v3>4</v3> </triangle> ... </region> </mesh> </object> </amf> Basic AMF Structure Addresses vertex duplication, leaks of STL & UNITS
  13. 13. Additive Manufacturing Compressibility Comparison for 32‐bit Floats; need to look at double precision
  14. 14. CURVED PATCH (Curved using vertex normals) PLANNAR PATCH Optionally add normal/tangent vectors  to some triangle mesh vertices  to allow for more accurate geometry.  CURVED PATCH (or curved using edge tangents) Curved patches
  15. 15. Additive Manufacturing Multiple Materials Micro- structureGradient Materials
  16. 16. Additive Manufacturing Print Constellation • Print orientation • Duplicated objects • Sets of different objects • Efficient packing • Hierarchical
  17. 17. Additive Manufacturing Metadata <metadata type=“Author”>John Doe”></metadata> <metadata type=“Software”>SolidX 2.3”></metadata> <metadata type=“Name”>Product 1></metadata> <metadata type=“Revision”>12A”></metadata> <object id=“1”> <metadata type=“Name”>Part A ></metadata> </object id=“1”>
  18. 18. Additive Manufacturing How do we build parts using AM? • 7 Process Categories – ASTM/ISO Standard terminology, categories & definitions will be used • What are the secret limitations you might not be aware of? • What types of materials can you use? • What is each process good for?
  19. 19. Additive Manufacturing Vat Photopolymerization • An additive manufacturing process in which liquid photopolymer in a vat is selectively cured by light- activated polymerization. – Stereolithography – Envisiontec DLP – Micro-SLA – 2-photon lithography – …
  20. 20. Additive Manufacturing Projection Systems • Use a projector (LED or DLP) to illuminate the cross-section – Resolution limited by pixels of projector – Typically faster per layer – Common for micro- stereolithography
  21. 21. Additive Manufacturing Envisiontec Perfactory
  22. 22. Additive Manufacturing Developments in Vat Photopolymerization • Increased proliferation of DLP/LCD/LED technology to cure entire layers at once. • New photopolymer materials which mimic engineering photopolymers • Expiration of initial stereolithography patents are opening up the marketplace • Renewed interest in 2-photon polymerization for nano-scale components
  23. 23. Additive Manufacturing Secrets of Vat Photopolymerization • Always need supports – Thus, we must remove them – Downward facing surfaces are inferior • Photopolymers do not have long-term stability in the presence of light – They continue to react and degrade over time.
  24. 24. Additive Manufacturing Materials in VP • Over 20 years of photopolymer research, including by major chemical companies, has led to many resins which you can buy • No materials are “standard engineering-grade” polymers – Specially-formulated to mimic engineering polymers
  25. 25. Additive Manufacturing What is VP best for? • High accuracy parts that don’t have stringent structural requirements • Patterns – Investment casting – RTV molding – …
  26. 26. Additive Manufacturing Material Jetting • An additive manufacturing process in which droplets of build material are selectively deposited – Wax or Photopolymers – Multiple nozzles – Single nozzles – Includes • Objet • 3D Systems Projet • Stratasys Solidscape machines • Several Direct Write machines • Etc…
  27. 27. Additive Manufacturing Single-Droplet • Solidscape Modelmakers – 0.0005” layers – small, accurate parts made slowly
  28. 28. Additive Manufacturing Multi-Droplet • Thermojet and Actua from 3D Systems – Prints waxy-like materials • No longer in production, but still serviced
  29. 29. Additive Manufacturing Developments in Material Jetting • New Stratasys/Objet Connex 500 – Multi-material & Multi-color • Many traditional “2D printing” companies are investigating 3D printing – Thermoplastics are difficult • Viscosity issues – Metals are starting to be publically discussed • Significant interest in printed electronics – Major industry interest at the intersection between 2½D & 3D geometries
  30. 30. Additive Manufacturing Secrets of Material Jetting • Always need supports – Thus, we must remove them – Downward facing surfaces are inferior (particularly true if secondary support materials are not used) • Secondary support materials make support removal easier – Water Soluble – Different Strength – Different Melting Temp
  31. 31. Additive Manufacturing Material Jetting Materials • Only commercial materials are wax-like materials or photopolymers – Need low viscosity – Waxes melt at low temperature, but solidify quickly – Photopolymers are cured using light just after deposition • No materials are “standard engineering-grade” polymers – Specially-formulated to mimic engineering polymers
  32. 32. Additive Manufacturing What is Material Jetting best for? • Smooth, accurate parts that don’t have stringent structural requirements • Mixing of stiff and flexible materials/colors gives tremendous variability in design – Artwork – Full-color mock-ups – Gradient material assemblies – …
  33. 33. Additive Manufacturing Binder Jetting • An additive manufacturing process in which a liquid bonding agent is selectively deposited to join powder materials. – Zcorp – Voxeljet – ProMetal/ExOne – …
  34. 34. Additive Manufacturing Developments in Binder Jetting • 3D Systems purchased Zcorp and has changed marketing to “Colorjet” – Printing sugary food and ceramics (pottery & art) – Announced a color personal 3D printer • ExOne is pushing “sand printing” and builds metal parts for Shapeways • Voxeljet, fcubic, etc. make marketplace dynamic – Continuous build platform design has major ramifications
  35. 35. Additive Manufacturing Secrets of Binder Jetting • Parts from starch/plaster look pretty but are quite brittle – Post-process infiltration of these materials by cyanoacrylate or another material is needed for strength • Infiltration makes these parts very heavy • Metal parts are not engineering-grade – Mostly applicable to art – Need infiltrated (highest accuracy) or sintered (shrinks)
  36. 36. Additive Manufacturing Binder Jetting Materials • Majority of the build material is the powder – Makes the process very, very fast • Materials are by nature “composite” • Gradients in color/properties possible by printing different binders • Any powder which can be spread and then glued, reacted, catalyzed, or otherwise fused using a binder is a candidate • Living tissue and dental ceramics are promising
  37. 37. Additive Manufacturing What is Binder Jetting best for? • Color parts used for marketing or proof-of- concept. • Metal parts for artistic purposes or with limited engineering functionality. • Powder metal green parts • Sand casting molds
  38. 38. Additive Manufacturing Material Extrusion • An additive manufacturing process in which material is selectively dispensed through a nozzle or orifice – Based on Stratasys FDM machines – Office friendly – DIY community – Best selling platform – …
  39. 39. Additive Manufacturing Developments in Material Extrusion • Expiration of initial FDM patents has led to a vast proliferation of personal 3D printers – More “personal” machines sold @$1k-$2k than “industrial” machines for $10k-$200k – Lots of new materials, competitors, etc. – Many ways for consumers to access & buy these machines • 3D Systems & Stratasys offer personal 3D printers in addition to their industrial offerings • Renewed interest in “manufacturing” parts via extrusion – High-temp materials, concrete, fiber-reinforced composites, etc. – People seem to be taking it more seriously than a few years ago
  40. 40. Additive Manufacturing Secrets of Material Extrusion • Always need supports – Thus, we must remove them – Downward facing surfaces are inferior • Secondary support materials make support removal easier – Water soluble, easier to remove, etc. • Fundamental tradeoffs in build style mean you can NEVER be fully dense & simultaneously achieve maximum accuracy without post-processing
  41. 41. Additive Manufacturing Material Extrusion Materials • Commercial materials include easy to extrude engineering polymers – ABS, PC, PC/ABS, PPSF, etc. – Chocolate and meltable food products – Many DIY materials being explored • Syringe & pumped nozzles also available – Pastes, glue, cement – Frosting & other food products • Need materials which soften under shear load and maintain their shape after deposition
  42. 42. Additive Manufacturing What is Material Extrusion best for? • Inexpensive prototypes • Functional parts without stringent engineering constraints – Limited fatigue strength • Great platform on which to try lots of things – Living tissue – Food – Toys
  43. 43. Additive Manufacturing Powder Bed Fusion • An additive manufacturing process in which thermal energy selectively fuses regions of a powder bed – SLS, SLM, DMLS, EBM, BluePrinter, etc. – Polymers, metals & ceramics
  44. 44. CO2 Laser X-Y Scanning Mirrors Feed Cartridges Part Cylinder Counter-Rotating Powder Leveling Roller Laser Beam Selectively Melts Powder SELECTIVE LASER SINTERING
  45. 45. 45 Loose Powder
  46. 46. 46 Energy is Applied – Laser or Electron Beam Energy Radiation/ Heat from Energy Source
  47. 47. 47 The Powder Begins to Heat Due to Incident Radiation
  48. 48. 48 The Outside of the Particles Heat More Quickly than the Inside
  49. 49. 49 Smaller Particles Begin to Melt
  50. 50. 50 Larger Particles May or May Not Melt Depending Upon Dwell Time of Radiation
  51. 51. 51 Melted Portions of the Material Begin to Coalesce (Sinter) Resulting in a Physical Bond and Shrinkage
  52. 52. 52 When the Heat is Removed, the Part Cools as a Porous Solid
  53. 53. 53 Melting within a Powder Bed Can Lead to Curl
  54. 54. 54 Melting within a Powder Bed Can Lead to Curl
  55. 55. 55 Melting within a Powder Bed Can Lead to Curl
  56. 56. 56 Melting within a Powder Bed Can Lead to Curl
  57. 57. 57 Undesirable Shrinkage Controllable Shrinkage Heater Scanning System Comparison of Shrinkage With and Without Heaters
  58. 58. 58 Undesirable Shrinkage Controllable Shrinkage Scanning SystemHeaterHeater Comparison of Shrinkage With and Without Heaters
  59. 59. 59 Undesirable Shrinkage Controllable Shrinkage Scanning SystemHeater Index Comparison of Shrinkage With and Without Heaters
  60. 60. 60 Undesirable Shrinkage Controllable Shrinkage Scanning SystemHeater Comparison of Shrinkage With and Without Heaters
  61. 61. Additive Manufacturing Metal Laser Sintering Methods for Controlling Shrinkage Complex Scan Patterns Supports
  62. 62. Additive Manufacturing Electron Beam Melting (EBM) Arcam • Electrons are emitted from a heated filament >2500° C • Electrons accelerated through the anode to half the speed of light • A magnetic lens focuses the beam • Another magnetic field controls deflection • When the electrons hit the powder, kinetic energy is transformed to heat. • The heat melts the metal powder No moving parts!
  63. 63. Additive Manufacturing EBM versus Laser Processes • EBM Benefits – Energy efficiency – High power (4 kW) in a narrow beam – Incredibly fast beam speeds • No galvanometers – Fewer supports • EBM Drawbacks – Only works in a vacuum • Gases (even inert) deflect the beam – Does not work well with polymers or ceramics • Needs electrical conductivity – Needs larger powder particles
  64. 64. Additive Manufacturing Developments in Powder Bed Fusion • The most-used platform for “functional parts” • Significant R&D investments • Many metal laser sintering machine manufacturers – SLM Solutions, ConceptLaser, EOS, Phenix, Renishaw, Realizer • Starting to see new polymer machine manufacturers – Several companies entering the marketplace to compete with 3D Systems & EOS • Open versus Closed machine architecture battles • GE’s purchase of Morris Technologies (2012) is still having major ramifications on the metal laser sintering marketplace
  65. 65. Additive Manufacturing Secrets of Powder Bed Fusion • An Expert User is the most critical aspect of getting a good part – User-selected trade-offs between speed, accuracy and strength in polymer laser sintering – Takes about a year to learn enough to consistently make good parts in metal processes • Polymers are not 100% recyclable • Metal supports are a huge pain – $50k-$100k/year per machine waste is common • Blade crashes and/or over-supporting
  66. 66. Additive Manufacturing Polymer Materials in Powder Bed Fusion • You can use any material you want, as long as it’s nylon – Or if it meets the cooling curve • Opposite of injection molding – Fast heating, slow cooling
  67. 67. Additive Manufacturing Metal Materials in Powder Bed Fusion • Most casting and welding alloys can be processed using metal laser sintering – Very fast melting & solidification times gives unique properties & challenges – High reflectivity, high thermal conductivity materials are difficult to process (copper, gold, aluminum, etc.) • Titanium is the “sweet spot” for EBM
  68. 68. Additive Manufacturing Other Materials in Powder Bed Fusion • Ceramics are difficult, but possible to directly process • Green parts are easy to process – Powder metallurgy, sand casting, etc.
  69. 69. Additive Manufacturing What is Powder Bed Fusion best for? • Manufacturing end-use products – Polymer parts from Nylon 11 or 12 (including glass- filled nylons) – Metal parts from Titanium, Stainless Steel, Inconel super alloys, tool steels and more • Prototyping components where functional testing is required on the prototype
  70. 70. Additive Manufacturing Sheet Lamination • An additive manufacturing process in which sheets of material are bonded to form an object. – Paper (LOM) • Using glue – Plastic • Using glue or heat – Metal • Using welding or bolts • Ultrasonic AM…
  71. 71. Additive Manufacturing Developments in Sheet Lamination • Renewed interest in paper-based machines at the low-end by Mcor and others • Fabrisonics sells 3 platforms based upon metal ultrasonic additive manufacturing • Other solid state AM methods are being investigated – Friction stir AM, etc.
  72. 72. Additive Manufacturing Secrets of Sheet Lamination • Getting rid of excess material is difficult – Cut then Stack – versus – Stack then Cut – Mechanical properties are typically quite poor
  73. 73. Additive Manufacturing Materials in Sheet Lamination • Paper is used for proof of concept parts – Color printing on the paper gives color parts • Metal sheets can be cut and stacked for tooling and other applications • Ceramic tapes can be cut and stacked and then fired for ceramic parts • Polymer sheets (such as by Solido) can be bonded and cut to form prototypes
  74. 74. Additive Manufacturing What is Sheet Lamination best for? • Paper machines make cheap physical representations of your design • Original LOM-like machines can be used like wood as patterns for sand casting, or as topographical maps, etc. • Metal laminated tooling reduces the time to build large molds such as for stamping • Micro-fluidic ceramic parts can be made using ceramic tapes
  75. 75. Additive Manufacturing – Wire & Powder Materials – Lasers & Electron Beams – Great for feature addition & repair Directed Energy Deposition • An additive manufacturing process in which focused thermal energy is used to fuse materials by melting as they are being deposited
  76. 76. Additive Manufacturing Developments in Directed Energy Deposition • Electron Beam with wire seems to be leading for part production currently • DoD is interested in laser powder deposition for repair (America Makes project) – Manufacturers are marketing laser deposition heads as add- ons to existing machine tools
  77. 77. Additive Manufacturing Secrets of Directed Energy Deposition • Material needs something to land on (supports) – We don’t typically make 3D complex parts, just complex parts with mostly upward-facing features • There is a direct correlation between feature size and build speed. – Accurate processes are painfully slow – Fast process are very inaccurate • Surface finish & accuracy requirements almost always require finish machining
  78. 78. Additive Manufacturing Materials in Directed Energy Deposition • Most metal alloys can be deposited with some success – Rapid cooling affects properties • Polymers and ceramics rarely used, but possible Optical Absorption vs Wavelength Wavelength (microns)
  79. 79. Additive Manufacturing What is Direct Energy Deposition best used for? • Adding features to existing structures – Replace complex forgings with sheet structures that we build up near-net shape parts on • Repair & refurbishment of existing components – Qualified for many high-performance applications
  80. 80. Additive Manufacturing General Comments • Powder Materials • Modeling • Implications of AM
  81. 81. Additive Manufacturing Powders • Small powder particles – Give better feature resolution, surface finish, accuracy and layer thicknesses – Are difficult to spread and/or feed – Become airborne easily (repel in EBM) – React with oxygen easily • Spherical powders with a tight PSD are best • Powder morphology, packing density, fines, etc. make a HUGE difference in some processes
  82. 82. Additive Manufacturing AM can now enable us to… …control the overall geometry of a part, which could be made up of a truss network, where each truss has an optimized thickness and could have an individually controllable microstructure or material. • But we don’t know how to: • Efficiently represent this type of multi-scale geometry in a CAD environment, or • Efficiently optimize these multi-scale features, or • Efficiently simulate the link between AM process parameters and microstructure, or • Efficiently compute the effects of changes in microstructure on part performance Courtesy David Rosen, Georgia Tech
  83. 83. Additive Manufacturing Simulation Needs • We need improved computational design tools for additive manufacturing • Like those used for injection molding and casting/forging • But, physics-based tools are inefficient when applied to AM • Requires dramatic simplification of the process and/or geometry • Instead, AM-industry software focuses primarily on geometry and not process control or performance/quality • Forces the AM industry to continue the Build/Test/ Redesign cycle of traditional manufacturing.
  84. 84. Additive Manufacturing • Process simulations that are faster than an AM machine builds a part – Predict residual stress and distortion so we know how to place supports and how to pre-distort our CAD model • Material simulations which can predict crystal level details and the resulting mechanical properties • Lightning fast solutions on GPU-based platforms • We simulate only what we need to get a practical answer as FAST as possible • Come tomorrow morning to hear more….
  85. 85. Additive Manufacturing Engineering Implications • More Complex Geometries – Internal Features – Parts Consolidation – Designed internal structures • No Tools, Molds or Dies – Direct production from CAD • Unique materials – Controllable microstructures – Multi-materials and gradients – Embedded electronics
  86. 86. Additive Manufacturing Business Implications • Enables business models used for 2D printing, such as for photographs, to be applied in 3D – Print your parts at home, at a local “FedEx Kinkos,” through “Shapeways” or at a local store • Removes the low- cost labor advantage • Entrepreneurship – Patents expiring • New Machines – Software tools – Service providers Pharmaceutical Manufacturing in China
  87. 87. Additive Manufacturing Web 2.0 + AM = Factory 2.0 • User-changeable web content plus a network of AM producers is already enabling new entrepreneurial opportunities – – Freedom of Creation – FigurePrints – Spore – …and more 87
  88. 88. Additive Manufacturing Impact on Logistics • Eliminates drivers to concentrate production • “Design Anywhere / Manufacture Anywhere” is now possible – Manufacture at the point of need rather than at lowest labor location – Changing “Just-in-Time Delivery” to “Manufactured- on-Location Just-in-Time”
  89. 89. Additive Manufacturing Big Picture Possibilities • Additive Manufacturing has the potential to: – Make local manufacturing of products normative • Small businesses can successfully compete with multi-national corporations to produce goods for local consumption • Parts produced closer to home cost the same as those made elsewhere, so minimizing shipping drives regional production – Reverse increasing urbanization of society • No need to move to the “big city” if I can design my product and produce it anywhere – Make jobs resistant to outsourcing • Creativity in design becomes more important than labor costs for companies to be successful 89
  90. 90. Additive Manufacturing Questions & Comments? +1-502-852-2509