2015 10-08 - additive manufacturing software 1
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The document discusses the advancements in additive manufacturing and its applications in medical fields such as orthodontics and tissue engineering. It outlines the process flow for additive manufacturing, including software used for CAD modeling, STL file generation, and image analysis for biofabrication. Additionally, it highlights the need for new file formats tailored to the additive manufacturing community to improve interoperability and functionality.
2015 10-08 - additive manufacturing software 1
- 2. + Question #1 07/10/2015
- 3. + Question #2 07/10/2015
- 4. MEDICAL APPLICATION OF RAPID PROTOTYPING
- 5. + Invisalign Orthodontic Aligners • An aligner for orthodontic use manufactured using a combination of rapid tooling and thermoforming. Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid. ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.
- 6. + Surgery
- 7. + Surgery
- 8. + Surgery
- 9. + Surgery
- 10. + Tissue Engineering - Biofabrication • Living cells are extracted from patients and seeded onto a carrier (scaffold) which accomodates and guides the growth of new cells in 3D within laboratory environment.
- 11. + Tissue Engineering - Biofabrication • STL Data produced from Micro-CT scan data • Multiple specimens of identical structure can be made, reducing samples variations.
- 12. OPEN QUESTION
- 13. + Open questions • WHICH ARE THE INTELLECTUAL PROPERTY IMPLICATIONS OF LOW-COST 3D PRINTING? • IS THE OPEN SOURCE 3-D PRINTING AN ENABLING TECHNOLOGY FOR SELF-DIRECTED SUSTAINABLE DEVELOPMENT? • CAN A 3D PRINTED ORGAN BE PATENTED?
- 15. + Additive manufacturing Process Flow • Solid Modelling • Tesselation/Generation of STL file • Support Generation • “Slicing” of the Model • Model Physical Buildup • Cleanup and Post Curing • Surface Finishing
- 16. + from idea to design
- 17. + from idea to design
- 18. + from design to object
- 19. + from design to object
- 20. + from design to object
- 21. + CAD FILE STL FILE GCODE 3D object Triangle and vertex Toolpath FreeCAD FreeCAD (MeshLab) Slic3r (CURA) Printrun to 3DP File Description Software Additive manufacturing Process Flow
- 22. + Additive manufacturing Process Flow CAD/CAM system Image acquisi on Inkjet based Direct wri ng
- 23. DATA SOURCE
- 24. + Data source • Representation of a volume – CAD model – Instruments output • CT • RM
- 25. + CAD model Dimensions of CAD Elements Elements Type of CAD Model 0D Point Corner Model 1D Line Edge Model 2D Surface Surface Model 3D Solid/Volume Solid or Volume Model
- 26. FROM MEDICAL IMAGES TO STL Example 1
- 27. + Segmentation • Segmentation subdivides an image into its constituent regiorns or objects. • The level to whhc the subdivision is carried out depends on the problem being solved
- 28. + Software per l’analisi delle bioimmagini • OsiriX (www.osirix-viewer.com) • 3DSlicer (www.slicer.org) • ImageJ (rsb.info.nih.gov/ij) • MIPAV (mipav.cit.nih.gov) • itk-SNAP (www.itksnap.org)
- 29. + Image Analysis: OxiriX imaging software • Advanced open-source DICOM PACS workstation • Image processing • Better communication with surgeons
- 30. + Geometry extraction • From original CT DICOM image to final volume • Semi-automatic procedure • Positive results in 95% of cases
- 31. + Osirix Plugins: edge preserving smoothing
- 32. + Osirix Plugins: Level-Set segmentation • Two algorithm – Shape detection – Geodesic Active Contours • Evolution based on – Propagation – Curvature – Advection • Programming principles d dt y = -aA(x)×Ñy -bP(x) Ñy +gZ(x)k Ñy R Malladi et al. Pattern Analysis and Machine Intelligence, IEEE Transactions on, 17(2):158 – 175, Feb 1995. V Caselles et al. International Journal of Computer Vision, 22(1):61–79, 1997.
- 33. + Osirix Plugins: Level-Set segmentation
- 34. FROM 3D SCAN TO STL Use of 123DCatch
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- 50. EXCHANGE FORMATS
- 51. + Stereolithograpy Interface • Stereolithograpy was first commercial Solid Freeform Manufacturing (SFM) process, released in 80’s by 3-D Systems • 3-D Systems developed interface between CAD systems and their machine • STL files (*.stl) allow CAD systems to interface with 3-D system machines • Virtually all subsequent SFM processes can use this same format (SFM industry standard) • Many CAD programs now can export the *.stl file for easy conversion from CAD to part
- 52. + STL Files (*.stl) • STL files were based on a program called Silverscreen CAD • Silverscreen CAD represent boundary with all surfaces being approximated by polygons or groups of polygons • *.stl files use triangles or groups of triangles to approximate surfaces • Accuracy depends on the triangle sizes (Smaller facets produce a higher quality surface) • Triangles assigned normal vectors for outward surface normal • Parts are defined by representing all their bounding surfaces as faceted surfaces, using the triangular patches
- 53. + STL Files (*.stl) • 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.
- 54. + Example of *.stl Representation Representing a sphere
- 55. + Example of *.stl Representation
- 56. + Existing Formats (1/2) • 3D PDF – Proprietary, closed • ISO 14649 (STEP-NC) – Mostly for NC control, G-Code • STEP / IGES, SAT, Parasolid – Too complex, missing features e.g. no mesostructure • X3D VRML – Mesh, color, texture, lighting All: no provision for AM, e.g. materials, internal structure
- 57. + Existing Formats (2/2) • PLY – 3D Scanner data • 3DS – Limited mesh size • SLC – Limited information All: no provision for AM, e.g. materials, internal structure
- 58. + New format needed • Tailor to AM community needs – No content constraints • Retain Community Control – Not Proprietary • Neutral – Avoids association with existing companies
- 59. + Desired features • simple • ISO 9000-ish features like product tracking • Interoperability within different manufacturers • Compatible with FEA applications • Identification of parent CAD program • Restricted number of printings • Support multiple shells • Editable ASCII/Text format
- 60. + Desired features • Information about build orientation • Stability/robustness • No redundancy • Volume validity • Lock or encrypt the file with a password • Ability to put a permanent ‘watermark’ • Supporting geometry in native way • Keep triangle mesh / No triangle mesh
- 61. + Reaching consensus, adoption • Non proprietary / open source • Endorsement by major CAD / Manufacturers • Use ASTM / Voting • Backwards compatible (STL) • Expandable, XML • Publish for comments / discussion • Open source software • Conversion tools • Limit the scope: Not a CAD model
- 62. + Current STL
- 63. + The new proposed format • AMF – Additive Manufacturing Format – Additive Manufacturing File
- 64. + XML • Meta-format: Format of formats – Text based – Easy to read/write/parse – Existing editing tools – Extensible – Highly compressible • Mentioned by a number of constituents – E.g. Materialise – Based on work by J. Hiller (Cornell) Addresses needs: Editable / Extensible / Readable / Open / Non proprietary
- 65. + General Concept • Part (objects) defined by regions and materials – Regions defined by triangular mesh – Materials defined by properties/names • Mesh properties can be specified – Color – Tolerance – Texture • Materials can be combined – Graded materials – Microstructure
- 66. + Basic Structure Addresses needs: Simple / Watertight / Backward Compatible (STL)
- 67. + Compressibility Addresses needs: Small / Compressible Need to look at dependency on # of digits
- 68. + Multiple Materials Addresses needs: Multiple Materials, No leaks between regions (shared vertices)
- 71. + Material properties • By manufacturer’s name – <Name> ABS </Name> – <Name>Tango Black </Name> – <Name>Nylon 1234 </Name> • By physical property – </Property Type=“Elastic Modulus” Value=“4E9”> – </Property Type=“Poisson Ratio” Value=“1.2”> • External reference (URL) Addresses needs: Material specifications/libraries
- 72. + Color and Graphics • By volumetric region – Solid color • By vertex – Specify Vertex color – Specify Vertex coordinate in a bitmap Addresses needs: Color graphics
- 73. + Color and Graphics
- 74. + Tolerances • By volumetric region – Nominal tolerance – Allowed variation from original volume • By vertex – Specify point tolerance (?) – Point to point Addresses needs: Tolerance
- 75. + Non-meshed geometry? • Other representations are not mutually exclusive • Voxel maps – For digital/inkjet microstructure • NURBS – Add slope vectors to some triangle mesh edges – Other STEP types? • Functional Representations – implicit equations NURBS PATCH PLANNAR PATCH
- 76. + NURBS PATCH PLANNAR PATCH Nurbs patch • Optionally add slope vectors to some triangle mesh edges to allow for very accurate geometry. – Perfect sphere can be made with ~20 patches
- 77. + Print Constellation • Print orientation • Duplicated objects • Sets of different objects • Efficient nesting • Hierarchical
- 78. + Metadata <Metadata> <Datum ID=“Author” Data=“John Doe”></Datum> <Datum ID=“Company” Data=“…”></Datum> <Datum ID=“Description” Data=“…”></Datum> <Datum ID=“Originating CAD System” Data=“…”></Datum> <Datum ID=“Originating CAD File” Data=“…”></Datum> <Datum ID=“Comment” Data=“…”></Datum> </Metadata>
- 79. + Encryption <Metadata> <Datum ID=“Author” Data=“John Doe”></Datum> <Datum ID=“Company” Data=“…”></Datum> <Datum ID=“Description” Data=“…”></Datum> <Datum ID=“Comment” Data=“…”></Datum> <Datum ID=“Encryption” Data=“Prompt”></Datum> </Metadata>
- 80. + Watermark / Copyright <Metadata> <Datum ID=“Author” Data=“John Doe”></Datum> <Datum ID=“Company” Data=“…”></Datum> <Datum ID=“Description” Data=“…”></Datum> <Datum ID=“Comment” Data=“…”></Datum> <Datum ID=“Copyright” Data=“Owner”></Datum> </Metadata>
- 81. + Other features • URL can be used in lieu of material data to allow for external libraries • Validation checksums – E.g. Original vs. actual part/region volumes • Automatic error checking – Readers/writers must check for intact topology, e.g. • All nodes referenced by at least 3 triangles • All edges referenced exactly twice per region
- 82. + ISO STANDARD