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
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Additive Manufacturing
Reshaping Manufacturing: Understanding 3D Printing Processes
Prof. Brent StuckerFounder & CEO, 3DSIM, LLC
Edward R. Clark Chair of Computer Aided EngineeringDepartment of Industrial Engineering, University of Louisville
Inaugural Chairman, ASTM F42 Committee on Additive Manufacturing
Additive Manufacturing
AM has the potential to enable anyone to make many things they
require, anywhere!
Additive Manufacturing
AM enables…
…an advanced manufacturing facility to be set up using only electricity, some raw materials, and a computer.
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.
Additive Manufacturing
AM is used for the…
…automatedmanufacture 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.
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
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
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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?
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– …
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
http://www.cmf.rl.ac.uk/latest/msl.html
Additive Manufacturing
Envisiontec Perfactory
www.ajm-magazine.com www.crdm.co.uk
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
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.
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
Additive Manufacturing
What is VP best for?
• High accuracy parts that don’t have stringent structural requirements
• Patterns– Investment casting– RTV molding– …
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…
Additive Manufacturing
Single-Droplet
• Solidscape Modelmakers– 0.0005” layers – small, accurate parts made slowly
Additive Manufacturing
Multi-Droplet
• Thermojet and Actua from 3D Systems– Prints waxy-like materials
• No longer in production, but still serviced
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
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
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
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– …
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– …
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
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)
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
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
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– …
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
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
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
Additive Manufacturing
What is Material Extrusion best for?
• Inexpensive prototypes• Functional parts without
• Great platform on which to try lots of things– Living tissue– Food– Toys
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
CO2 LaserX-Y Scanning
Mirrors
FeedCartridges
PartCylinder
Counter-RotatingPowder LevelingRoller Laser Beam
SelectivelyMelts Powder
SELECTIVE LASER SINTERING
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Loose Powder
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Energy is Applied – Laser or Electron Beam Energy
Radiation/Heat from
Energy Source
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The Powder Begins to Heat Due to Incident Radiation
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The Outside of the Particles Heat More Quickly than the Inside
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Smaller Particles Begin to Melt
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Larger Particles May or May Not Melt Depending Upon Dwell Time of Radiation
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Melted Portions of the Material Begin to Coalesce (Sinter) Resulting in a Physical Bond and Shrinkage
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When the Heat is Removed, the Part Cools as a Porous Solid
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Melting within a Powder Bed Can Lead to Curl
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Melting within a Powder Bed Can Lead to Curl
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Melting within a Powder Bed Can Lead to Curl
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Melting within a Powder Bed Can Lead to Curl
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Undesirable Shrinkage Controllable Shrinkage Heater Scanning System
• 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)
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
Additive Manufacturing
General Comments
• Powder Materials• Modeling• Implications of AM
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
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
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.
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 leveldetails 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….
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
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
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– Shapeways.com– Freedom of Creation– FigurePrints– Spore– …and more
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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”
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