learning biology through 3d printing
TRANSCRIPT
Learning Objectives • Introduce 3D printing operation theory • Show how 2 distinct types of CAD software
(parametric and mesh modeling) can be adapted to 3D printing applications
• Engage in an Anatomy bone labeling exercise
• Reveal difficulties that our grant faced when initiating this 3D printing curricula
• Summarize resources available to instructors
National Science Foundation Advanced Technological Education MODEL 3D Modeling Original Didactic Experiences in Learning 3D • Website 3d.waketech.edu • Twitter @waketech3D • Instagram @waketech3D • Email [email protected]
http://3dprintingindustry.com/3d-printing-basics-free-beginners-guide/technology/
What is 3D Printing? • The translation of digital
information into a physical object.
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• Insert introductory video
What is 3D Printing?
Operation Theory
• 3D printing is also known as additive manufacturing and rapid prototyping.
• 3D printers build objects by adding material layer by layer.
• 3D printers differ from traditional CNC machines that subtract a substance from a starting block of raw material.
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Additive
https://thecynicalchef.files.wordpress.com/2008/11/pancakes-047.jpg
Subtractive
http://cdn6.bigcommerce.com/s-lz5sf2/product_images/uploaded_images/what-is-whittling-knife.jpg?t=1455310108
Overview of 3D Printing • There are 3 common 3D printing techniques:
1) Binder Jet Printing (powder particles are bound or fused together)
2) Stereolithography (liquid resin is hardened by a laser beam or light)
3) Fused Filament Fabrication (plastic filament string is melted and deposited)
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Fused Filament Fabrication
• A spool of filament (typically plastic) is fed into a hot metal tip.
• Computer controls direct the hot metal tip to extrude and deposit melted filament onto a print bed.
• Additional melted filament is deposited and adheres to the preceding layers and an object is formed layer by layer.
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Fused Filament Fabrication
3D Printing is Nothing Special
• Making plastic widgets via Fused Filament Fabrication is very similar to making plastic widgets with plastic injection molding.
http://2.wlimg.com/product_images/bc-full/dir_35/1047127/injection-plastic-molding-763014.gif
Injection Molding
Creating Filament on Spool
Loading Filament from Spool
Nothing New… • Binder Jet RF Housholder
1979. Commercialized by Dr. Carl Deckard & Dr. Joseph Beaman in the 1980’s.
• STL Alain Le Mehaute 1986. Chuck Hull commercialized it in 1986.
• FFF Scott Crump invented in 1988.
http://3dprintingforbeginners.com/wp-content/uploads/2015/10/Femur-printed-on-Makerbot-Replicator-2.png
http://aptgadget.com/wp-content/uploads/2015/08/TRUMPF_DepositionLine.jpg
http://www.xconomy.com/wordpress/wp-content/images/2015/08/Carbon3D-Printer.jpg
Why All the Recent Attention?
• 2 companies, Stratasys and 3D Systems, bought 3 patents for 3D printing techniques.
• Patents began to expire in 2014 (25 years after creation).
• Reprap and open source improvement of printers
• “Maker” movement utilizes open source technology & inexpensive microcontrollers like Arduinos & Raspberry Pi to spur innovation.
https://upload.wikimedia.org/wikipedia/en/8/8c/3D_Systems_Logo_-_from_Commons.gif
https://www.3printr.com/file/2015/10/Stratasys-3.png
http://www.sloma.org/images/makers2014.png
3D Printer Uses
• Custom/ Promotional Materials
• Fashion
• Medical
• Art
• Impossible geometries http://www.slashgear.com/nefertiti-bust-secretly-scanned-3d-model-released-to-public-24428989/
Considerations for 3D Printing Objects
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http://3dprintingindustry.com/3d-printing-basics-free-beginners-guide/technology/
Orientation vs Grain
• Orientation vs grain animation-done • Overhangs animation-done
Overhang
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Generating 3D File Information
Mesh Becomes Sliced Layers
Layer Height
Infill Percentage
No Supports
With Supports
Infill and Layer Height
http://www.quora.com/Why-do-3d-printers-use-a-honeycomb-structure-to-print-out-objects http://blog.teambudmen.com/2013/09/understanding-shells-layer-height-and.html
http://enablingthefuture.org/2014/11/13/tech-talk-thursday-intro-to-3d-printing/
Why Do you want a 3D Printer?
-Is your end goal to create a usable product? -Will it mostly be used for rapid prototyping? -What sort of detail will you need? -What material fits your needs? Is the material cost effective? -What size objects will you produce?
Printer Specifications to Consider
http://www.protoparadigm.com/news-updates/tag/printer_theory
Grant Courses Cross Divisions Technical (students design printed part)
Non-technical (part is printed as learning tool)
ASSOC. ENGINEER. TECH. -EGR 285 (capstone) - DFT 154 Intro to Solid Modeling -TDP 110 Intro 3D Printing COLLEGE TRANSFER -DFT 170 Engineering Graphics (Solidworks) -MAT 273 Calculus III -PHY 251 Physics 1 -BIO 111 Biology I -BIO 168 Anatomy & Physiology I
1) Strengthen Curriculum
2) Improve Student Learning Performance & Industry Skill Acquisition
3) Collaborate with Industry & Educational Partners
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Goals and Courses
BIO 111 BIO 168
DFT 170
PHY 251
EGR 285 TDP 110 DFT 154
MAT 273
Creating 3D Printed Learning Tools
• The proposed 3D printed objects for our non-technical courses, Calculus and Physics, could either be found in a CAD library online
• OR parametrically modeled by students in our drafting classes
Traditional 3D MODEL CAD Libraries • Makerbot’s Thingiverse • AUTODESK 3D Model Library • GrabCAD • Shapeways • SketchFAB • SketchUp 3D WAREHOUSE • Turbosquid • Yeggi
BIO 168 Project Parameters • Idea: reproduce plastic anatomy models • 3D printed models would complement existing
learning tools: computer 3D model viewer, bone models in the classroom, & textbooks • Students are tested on real bones in class so
there was a digital to tactile disconnect
Labeling Activity • Areas students consistently
struggled: 1) saggital (cross-section) view of skull 2) hand bones 3) feet bones • You’ll find our 3D printed labeling
activity and paint pens at your seats • Share and use the same color with
different patterns for several bones
Label Foot Bones
Label Hand Bones
Issues With printing Anatomy Bones • Non-technical class so we looked for anatomy
models in online libraries • Models requested by instructors either didn’t exist,
were too detailed or were not detailed enough
Finding Medical Quality 3D Scans
• Thingiverse http://www.thingiverse.com/
• Embodi3D http://www.embodi3d.com/
• NIH 3D Print Exchange http://3dprint.nih.gov/
• Morphosource http://morphosource.org/
Why No Free Models Online? • New technology (low cost 3D printers are only a few years old) • Animation and medical modeling is very time intensive skilled
work. Modelers don’t want to give away their work for free • There are CAD files for creating the plastic molds (negatives)
for models you can buy from traditional companies • Once the file is shared online, there’s no going back
Parametric Modeling vs Mesh Modeling
• 3D printers work best for items that are designed in a parametric 3D modeling program
• I.e. Solidworks, AutoCAD, SketchUp, Inventor, Fusion360 etc.
• The designer chooses the shape, angle, dimensions, and thickness of the object
• 3D printers handle parametric models well because human design is typically based on simple geometry at the human scale
• 3D printers translate printed information on an X, Y, Z coordinate plane system
• Mesh models represent organic shapes more accurately but are hander to physically realize
Parametric Modeling vs Mesh Modeling
Generating Mesh File Data • Since Mesh is just connected polygons (triangles
or “T” splines) there are no guiding parameters • Mesh model detail depends on quality of scanner • Higher quality scanner=more polygons in mesh
Mesh Models were Too Detailed • 3D Medical scanners, like MRI and CT machines
scan everything: bumps, holes, imperfections, even marrow inside of the bones.
• We just need a representative model of the exterior “shell”
Necessary Model Specifics • Bones must be connected to each other • Need to still show the detail of the bon edges to see
how and where they connect Thingiverse Trial 30% scale model Final Morphosource 100% scale model
A Note On Tools
• Fusion360
• Meshmixer
• Zbrush
• Avizo
• Materialise
Learning Limitations of Our 3D Printers
• Bowden tube vs direct drive mechanisms • Our F306 3D printers have a long Bowden
tube and experience a great amount of retraction
Direct Drive Feed
Starting to Get Success • Printed on Makerbot’s direct drive (no Bowden tube) • Printed a prepared & hollowed out anatomy file • Filament supplier was a new company with bad
manufacturing quality control • Sent it back because of inconsistent diameter
http://www.protoparadigm.com/news-updates/filament-tolerances-and-print-quality/
Irregular Filament
http://www.protoparadigm.com/news-updates/filament-tolerances-and-print-quality/
Temperature change
Ambient Moisture
Physical Damage
In 12 months filament degrades due to UV exposure and moisture
absorption and becomes unusable
Environmental Influences on Print
More Printer Limitations • Makerbot’s axes are driven by stiff rubber belts
not kevlar string • Belts can only move linearly • Wrapped kevlar stretches and moves out of line
Fused Filament Fabrication
Future Projects • Help from Duke’s Evolutionary Anthropology
Department • Free used funds for MicroCT machine • Can clean up models with professional quality
medical modeling software
Printing Considerations
• Finding high quality detailed files • Bones that were connected • Hollowed out interior and simplified exterior • Type of printer (bowden vs direct drive) • Axes controlled by kevlar vs rubber belt • Filament quality • Deleted unnecessary extra information (carpals
and tarsals) to save time, filament and complexity
Recap of Resources:
Recap of Resources
• Website 3d.waketech.edu • Twitter @waketech3D • Instagram @waketech3D • Email [email protected]
Any Questions?
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