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

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

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

Pros & Cons Pros: Cons Fast prototyping Small size 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

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

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

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

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

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

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

Other technologies Robocasting or Direct Ink Writing (DIW) Digital Light Processing (DLP) Electron-beam melting (EBM) Electron Beam Freeform Fabrication (EBF3)

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

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!

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

OpenSCAD Open sourced and free to use

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