3D Printing Seminar

What is 3D Printing?


Text STL File


Iterative Design Presentation


  • Ways of manufacturing things:
    • Material removal
    • Forming
    • Casting
    • Additive
      • Hard Facing
      • Plating (electrotyping)
      • Metal Spraying
      • Coil Pottery
  • Tool-less fabrication of plastics
    • Cost of Change Diagram
  • Traditional plastics processes
    • Injection molding
    • Expense of tooling
  • At first, used as prototypes
    • Meaning of prototype
    • Uses for a prototype
      • Aesthetic appeal
      • Fit
      • Function
      • Manufacturing feasibility
    • Other ways of making prototypes

The Technologies

  • Stereolithography
    • Photo curing polymer
    • Explanation
    • [SLA] Charles Hull – 1984 – Apparatus for production of three-dimensional objects by  stereolithography US 4575330 A
    • Founded 3d Systems
    • 1987 SLA-1 (first commercial system)
  • Expansion into other methods
  • [SLS] Carl Deckard – 1989 – Method for selective laser sintering with layerwise cross-Scanning
    • US 5155324 A
  • (DTM, Inc. – sold to 3D systems)
  • [FDM] Scott Crump – 1989 (STRATASYS) Fused Deposition modeling
  • [DMLS] Hans Langer EOS GmbH
    • Direct Metal Laser Sintering
  • [BPM] Ballistic Particle Manufacturing
    • Objet
  • [DBM] Droplet-Based Manufacturing (includes Z corp)
    • Droplets as binders (Z Corp)
    • Began to be called 3D Printing (MIT Trademark)
  • [LOM] laminated Object Manufacturing
  • Emerging technologies – Printing Circuits, bioprinting, etc.
  • Breakoff of FDM to hobby sector (2004 Dr. Bowyer & Reprap)

Uses of 3d Printed Objects

Prototypes & Mockups of plastic and other components

1) Advantage: Can make parts that can’t be made

  • Inj. Molding Restraints
  • Mold parting
  • Wall thickness
  • Mold Required

2) Disadvantage: Can make parts that can’t be made

  • Does not show how difficult to mold
  • Does not reflect mechanical props of molded
  • But…Some models can be used as rapid tooling

Rapid Tooling

  • Casting tooling
  • Patterns & Molds
  • Injection mold tooling

As an Additive Manufacturing Process

  • Slow
  • Resolution low (by comparison)
  • Often requires post processing
  • Many advantages
    • Custom designs
    • Freeform interior cavities

How the process works

  • CAD Model – many formats (STEP, IGES, DXF, DWG, PRT…)
    • OR Scanned Geometry
  • STL File (Surface Mesh)
    • Tessellation
  • Slicing – contour generation &
  • G-Code Generation
  • CNC Equipment
    • (sometimes Host Software)
    • About CNC Machining
      • Differentiate b/t 3D Printing
  • Firmware on Controller
  • Motor Drivers

Actual Workflow

  • 3D CAD programs
    • Autodesk
    • Inventor
    • Autodesk 360
    • PTC Creo (formerly pro Engineer)
    • DSS SolidWorks
    • DSS Catia
    • Siemens NX (Unigraphics)
    • Siemens Solid Edge
    • Blender
    • Sketchup
    • Tinkercad
    • Cubify

Basics of 3D CAD

3D Space

Need Volume to be defined

Points, lines, arcs, planes cannot be printed

CSG Vs. BRep

Boolean Venn Diagrams


Exist on a plane


Swept Shapes



Sweeping along guide

Apply Booleans,






Basics of Slicing STL

FDM Printer Process Variables

Extrusion Speed

Extruder head speed

Temperature of Base

Temperature of Extruder Head

Support options

Raft options

Wall thickness options



Model Placement

Orientation is important

Parts are anisotropic


Material Variables

Melting point

Creep resistance



Post Print Processing

Raft & Support Removal


Painting & Coating

Other processes require different post-print processes



Health issues

Legal& Ethical issues, copyright, trademark law,  gun printing, etc.

 See: Print the Legend

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