Ken YoussefiENGR 10 D. T. Pham, S. S. Dimov, Rapid manufacturing, Springer-Verlag, 2001, ISBN: X, page 6

Ken Youssefi Rapid Prototyping Processes Through out the years, many different production processes have been used to create prototypes (cast metal molds, epoxy molds, silicon rubber molds, injection molding, …..). But in recent years, due to sophisticated computer software (3D parametric modelers), Rapid Prototyping has emerged as the preferred process for many application. Rapid Prototyping Solid freeform fabrication involves constructing a three dimensional object one cross sectional layer at a time, depositing a material or by solidifying liquid or bonding powder. The object is first created using a 3D parametric modeler (Pro/E, Unigraphics, SolidWorks, …). The commercial rapid prototyping process can be categorized as extrusion, stereolithography, laser fusion, inkjet printing (3D printing) and lamination.

Ken YoussefiENGR 10 Inkjet Printing – 3D printing You create a 3D model of your object in a CAD program and save it as an.stl file A special software chops the CAD model up into thin layers typically 5 to 10 layers/millimeter. The 3D printer's inkjet prints one layer at a time, much like 2D printing. Liquid binder is used in place of ink to bond the powder. Special bonding agent (epoxy or Zbond) is brushed on to strength the model This process repeats, layer by layer, until the model is complete. Depending on the size of the object and the no. of layers, the process could take from 20 min. to 12 hours. The build platform drops down a fraction of a millimeter (one layer), a fresh layer of powder is spread out and the machine prints the next layer.

Ken YoussefiENGR 10 3D printing 3D solid model of the object The part is divided into slices Only 10% of the slices are shown

Ken YoussefiENGR 10 Rapid Prototyping Processes – ZPrint Harden Powdered Models Binder Powder storage Ink storage, replaced by the binder Colored 3D printer

Ken YoussefiMechanical Engineering Dept. Rapid Prototyping Processes - ZPrint Piston raises for the next layer, powder is spread over the build area, enough for one layer. Standard inkjet printhead Roller spreads a layer of powder material FeedBuild Piston lowers making room for new layer

Ken YoussefiENGR 10 ZPrint - examples Concept Modeling Size: 21 x 33 x 20 cm Printing Time: 12 hours Consumer Products Size: 8 x 18 x 5 cm Printing Time: 2 hours Medical Size: 25 x 20 x 10 cm Printing Time: 5.5 hours Footwear Size: 10 x 30 x 5 cm Printing Time: 3 hours Automotive Size: 25 x 28 x 11 cm Printing Time: 8 hours