1. 3D Printing
Yingcai Xiao

2. 3D Printing
What and How
Categories
3D Model Creation
File Formats
Printers
Applications
Services
Challenges

3. What is 3D Printing?
A manufacturing process
3D objects
Additive (one layer at a time)
According to 3D models

4. What is 3D Printing?
"Rapid prototyping slicing" by Materialgeeza - Own work. Licensed under CC BY-SA 3.0 via Commons -

5. How does it work?
Additive: one layer at a time
Common methods for producing layers:
FDM, SLS, SLA
FDM: fused deposition modeling
SLS: selective laser sintering
SLA: stereolithography

6. Categories of Additive Manufacturing
(American Society for Testing and Materials)
Extrusion Deposit
Vat Photopolymerisation
Material Jetting
Binder Jetting
Powder Bed Fusion
Sheet Lamination
Directed Energy Deposition

7. Extrusion Deposit A.k.a: fused deposition modeling (FDM)
Most commonly used
Prototyping
Inexpesive
"FDM by Zureks" by Zureks - Own work. Licensed under GFDL via Commons -

8. Extrusion Deposit Structure of an Extruder Demo of FDM
"Extruder lemio" by Lemio - Licensed under GFDL via Commons -

9. Extrusion Deposit Extrusion Materials
acrylonitrile butadiene styrene (ABS)
polylactic acid (PLA)
high-impact polystyrene (HIPS)
thermoplastic polyurethane (TPU)
aliphatic polyamides (nylon),
Polyether ether ketone (PEEK)
paste-like materials (ceramic, chocolate, …)

10. Powder Bed Fusion E.g.: Selective laser sintering (SLS)
"Selective laser melting system schematic" by Materialgeeza - Own work. Licensed under CC BY-SA 3.0 via Commons -

11. Powder Bed Fusion Selective laser sintering (SLS)
Developed in 1980s at UT Austin
Patent expired 2014
Materials: metals, polymers, nylon
In powder form.
Un-melted powder becomes supporting material.

12. Vat Photopolymerisation
Examples:
SLA (stereolithography)
CLIP (Continuous Liquid Interface Production)
"Stereolithography apparatus" by Materialgeeza - Own work. Licensed under CC BY-SA 3.0 via Commons -

13. Material Jetting Image source: CustomPartNet

14. Binder Jetting
Image source: additively.com

15. CAD (Computer-Aided Design) software e.g.: AutoCAD (free for students)
3D Model Creation
3D Scanners
e.g.: Kinect
CAD (Computer-Aided Design) software
e.g.: AutoCAD (free for students)
Visualization software
e.g. VTK

16. STL: STereoLithography By 3D Systems Triangulated surface meshes
3D Print File Format
STL: STereoLithography
By 3D Systems
Triangulated surface meshes
ASCII or binary
No unit
No color

17. 3D Print File Format 3MF: 3D Manufacturing Format www.3mf.io
Geometries (Triangulated, NURBs, …)
Materials (Color, Texture, Composite)
Open source

18. 3D Print File Format

19. 3D Print File Format 3MF: 3D Manufacturing Format www.3mf.io Microsoft
Consortium
Microsoft donated code reads STL/OBJ/3MF, writes 3MF

20. 3D Print File Format 3MF Example created by Kinect
Supported in Windows 10

21. 3D Printers
Prusa (RepRap.org)
MakerBot Replicator
LulzBot TAZ
MakerGear
Formlabs
Ultimaker
Polymaker (printing materials)

22. Applications Prototyping Manufacturing (cars, houses,..) Arts
Entertainment
Medicine
Food
Personal
Started here 9/22

23. 3D Printing Services
Printing Services:
Sculpteo
Ponoko
Shapeways

24. 3D Printing Services
Model Services:
Pinshape
CGTrader
MyMiniFactory
Thingiverse
Yeggi

25. Challenges in 3D Printing
True color objects
Supporting curved objects in FDM
Voxelization (non smooth surface and internal fracture)

26. Infographics by Sculpteo
Summary
Infographics by Sculpteo

27. 3D Data Representation
Yingcai Xiao

28. Characteristics of Data
DiscreteInterpolation
P1, P2
Regular/Irregular
Data Dimensions

29. Data Structure Design Criterion
Compact (save space)
Efficient (fast retrieval)
Map-able (easy to convert)
Minimal Coverage (small foot prints)
Simple (easy to use)

30. Dataset Data objects in the visualization pipeline are called datasets
consisting of two pieces: an organizing structure and supplemental data attributes.

31. Dataset Structure: topology and geometry
Topology: is the set of properties invariant under certain geometric transformations.
Geometry: is the instantiation of the topology; the specification of positions in a 3D space.
VTK Model: the structure consists of cells and points. The cells specify the topology; while the points specify the geometry

32. Dataset Dataset Attribute: Data to be visualized.
Associated with each point.
Typical attributes: color, texture, and user-defined data.

33. Cell Types A data set consists of one or more cells
A cell is defined by a “type” and an ordered list of point
Type: topology, cell type
Ordered list: geometry, points
Together: organizational structure
Use Set: all the cells using a point:
U(pi) = {Ci: pi Ci}

34. Cell Types
Vertex: zero-dimensional cell, It is defined by a single point.
Line: one dimensional cell. It is defined by two points.
Polyline: is a composite one-dimensional cell consisting of n connected lines. It is defined by an ordered list of n+1 points.
Triangle: is a primary two-dimensional cell. The triangle is defined by a counter-clockwise ordered list of three points.
Polygon: is a primary two-dimensional cell. The polygon is defined by an ordered list of three or more points lying in a plane
Tetrahedron: is a primary three-dimensional cell. It is defined by a list of four nonplanar point.

36. Attribute Data
Attribute data is information associated with the structure of the dataset. It is what to be visualized.
Dataset Attribute Model
Scalars
Vectors
Normals
Texture Coordinates
Tensors (The rank of a tensor is the dimension of the matrix containing its values.)
User-defined

37. Type of Datasets Dependent on topology of the dataset.
Uniform Grid (uniform in each direction)
Parameters:
Dimension: nx, ny, nz
Origin: x0, y0, z0
Spacing: dx, dy, dz

38. Rectlinear Grid IJK space. x = x[I]; y = y[J]; z = z[K];
Data array (i, j, k), i changes first, then j, k last.
Simple
compact (takes O(nx + ny + nz) more space)
speedy retrieval
Little more flexible

39. Structured Grid Dimension: nx, ny, nz Nonuniform spacing
IJK space (no formula)
Coordinates of each grid node need to be given.
x(I,J,K), y(I,J,K), z(I,J,K)

40. Most Adaptable Data Set:

41. Unstructured Grid No dimensions parameters: nx, ny, nz No IJK space
Coordinates of each node need to be given
Most flexible, can represent any structures of data
Not compact (need space to save xyz values and cell information)
Slow retrieval

42. Data Set Internal Memory Structure

43. Unstructured Surface Polygonal Surface
No dimensions parameters: nx, ny, nz
No IJK space
Coordinates of each node need to be given
Data value(s) on each node needs to be given

44. Structure Representation
P1 of T1 and P2 of T2 are connected at P(1,0,0)

45. Structure Representation The Wrong Way: Making Copies
class Tri { public: point P1, P2, P3; };
Tri T1, T2;
T1.P1.x=1.0;
T1.P1.y=0.0;
T1.P1.z=0.0;
…….
T2.P2.x=1.0;
T2.P2.y=0.0;
T2.P2.z=0.0;
………

46. Structure Representation: Wrong Way
Each triangle keeps a copy of the vertex values.
Drawback: if the coordinate of P is changed, all cells having a copy of its value need to be updated.

47. Structure Representation: Correct Way
Save the vertex values in an array (Point List).
Store the indexes of the vertexes for each triangle in the triangle definition  

48. Structure Representation The Correct Way: Indexing
P2.x=1.0;
P2.y=1.0;
P2.z=0.0;
P3.x=0.0;
P3.y=1.0;
P3.z=0.0;
Point List
P0.x=0.0;
P0.y=0.0;
P0.z=0.0;
P1.x=1.0;
P1.y=0.0;
P1.z=0.0;

49. Structure Representation The Correct Way: Indexing
class Tri{ public: int ID1, ID2, ID3; };
Tri T1, T2;
T1.ID1=0;
T1.ID2=1;
T1.ID3=3;
T2.ID1=1;
T2.ID2=2;
T2.ID3=3;

50. Structure Representation: The Correct Way: Indexing
Each triangle keeps an index list (cell list) of its vertexes.
If the coordinate of P is changed, none of the cells using it needs to be changed. Only the one copy of its value in the point list needs to be updated.

51. Dataset Structure: topology and geometry
Topology: is the set of properties invariant under certain geometric transformations.
Geometry: is the instantiation of the topology; the specification of positions in a 3D space.
VTK Model: the structure consists of cells and points. The cells specify the topology; while the points specify the geometry

52. Data Set Internal Memory Structure

53. Summary of VTK Data Structures