This document provides an introduction to 3D printing, including a brief history, pros and cons, different technologies used, popular 3D printer brands, 3D modeling, and online resources. It explains that 3D printing involves building solid objects layer by layer from a 3D digital model, and that common technologies include extrusion (FDM), light polymerization, and powder bed methods using heat, lasers, or liquid binding to fuse materials together. The document also notes that while 3D printing enables fast prototyping and less waste than traditional methods, prints can be small and slow with limited material choices.

1. 3D printing workshop
Introduction to 3D printing
Instructor: ChungTsz Him (thchung@cse.cuhk.edu.hk)

2. What is 3D printing?
• 2D printing means printing on a surface(2D), e.g. paper printer
• 3D printing means printing solid objects by adding materials layer by layer
• Input a 3D-model
• Printing by printer
• Can use plastic, polymers, or even metal

3. History
• Actually not a new technology
• Charles Hull invented in 1984
• Become popular in recent years
• Due to advanced technology and lower cost

4. Pros & Cons
• Pros:
• Fast prototyping
• Lower costs
• Less setup and wasted materials comparing to
Molding(注塑成型), forging(鍛造) and
casting(鑄造)
• Cons
• Small size
• Few choices of materials
• Slow printing

5. Technology
• Extrusion – Fused deposition modeling(FDM)
• Heat and melt the materials first
• Then “extrude” material layer by layer
• Can use different kinds of materials (mostly plastic and clay)
• Used by the 3D printer in the IT Clinic
• Inexpensive BUT
• Slow and not accurate

6. • Light polymerized - Stereolithography
• Laser shoot on liquid photopolymer
• Liquid react with laser and become solid
• Accurate and can print large object, BUT
• Laser is dangerous and expensive

7. • Powder Bed - Selective heat sintering (SHS) / Selective laser sintering (SLS)
• Apply heat or laser on thermoplastic powder
• Powder sinter (but not yet melt)
• Very complicated and expensive

8. • Powder Bed - Direct metal laser sintering (DMLS)
• Similar to SLS
• BUT used on metal
• Powder Bed - Selective laser melting (SLM)
• Similar to SLS
• BUT will melt the metal powder
• Can print very hard materials, e.g.Titanium alloys, stainless steel

9. • Powder Bed - Powder bed and inkjet head 3D printing (3DP)
• Similar to SLS
• BUT use liquid binding material to combine the powder instead of laser
• Faster than laser
• BUT the powder may stick on the object

10. • Laminated object manufacturing (LOM)
• Use laser cuter to cut the adhesive-coated sheet of materials
• Low cost
• Can build large part BUT
• Less accurate than SLS

11. • Other technologies
• Robocasting or Direct InkWriting (DIW)
• Digital Light Processing (DLP)
• Electron-beam melting (EBM)
• Electron Beam Freeform Fabrication (EBF3)

12. 3D printer brands
• Makerbot (used in IT clinic)
• Movehand (a HK company)
• Tiertime
• Velleman

13. 3D modeling
• A 3d model file is STL file, e.g. ABC.stl
• Can use Computer-aided design (CAD) or 3D modeling software to build
• OR simply download from the internet!

14. Autodesk 3ds Max
• Student can create account and download for free

15. OpenSCAD
• Open sourced and free to use

16. Online resource
• Makerbot thingiverse:
• http://www.thingiverse.com/
• Youmagine
• https://www.youmagine.com/