Ken Youssefi ENGR 10

D. T. Pham, S. S. Dimov, Rapid manufacturing, Springer-Verlag, 2001, ISBN:1-85233-360-X, page 6

Ken Youssefi

Rapid Prototyping ProcessesThrough 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 Youssefi ENGR 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 Youssefi ENGR 10

3D printing

3D solid model of the object The part is divided into slices

Only 10% of the slices are shown

Ken Youssefi ENGR 10

Rapid Prototyping Processes – ZPrintHarden Powdered Models

Binder

Powder storage

Ink storage, replaced by the binder

Colored 3D printer

Ken Youssefi Mechanical 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 spreadsa layer ofpowder material

Feed BuildPiston lowers making room for new layer

Ken Youssefi ENGR 10

ZPrint - examples

Concept ModelingSize: 21 x 33 x 20 cmPrinting Time: 12 hours

Consumer ProductsSize: 8 x 18 x 5 cmPrinting Time: 2 hours

MedicalSize: 25 x 20 x 10 cmPrinting Time: 5.5 hours

FootwearSize: 10 x 30 x 5 cmPrinting Time: 3 hours

AutomotiveSize: 25 x 28 x 11 cmPrinting Time: 8 hours