Rapid Prototyping

Rapid Prototyping Laminated Object Manufacturing Selective Laser Sintering Stereolithography Fused Deposition Modeling Solid Ground Curing 3D Printing

What is Rapid Prototyping • Builds parts Layer-By-Layer • Class of technologies that construct physical models from CAD data • Some what like a 3-D printer • An Additive process • Visual Aids or Design Testing • Rapid Tooling or Rapid Production of parts

The Basic Process • Create a CAD model of the design • Convert the CAD model to STL format • Slice the STL file into thin cross-sectional layers • Construct the model one layer atop another • Clean and finish the model

CAD MODEL • Build a Model • Solid Modeler Packages • Such as Pro-Engineer tend to represent objects more accurate then wire frame packages • Yield better results • Existing CAD or Create a model for RP

Conversion to STL • STL Format • Establish consistency • ****.stl – stereolithography, the first RP technique • Represents a 3-D surface in an assembly of planar triangle • Like facets of a cut jewel • Planar elements • Can not represent curve surfaces exactly • Accuracy vs. manageability

Conversion to STL

The Slice • Pre-processing program • Prepares STL file for build • Most program allows user to adjust the model • Size • Location • Orientation

The Slice • Orientation • Weaker and less accurate in the Z direction then in the x-y plane • Orientation partially determines the amount of time for build • Higher in the Z – lot more time to build • Place shortest dimension in the Z • Reduces the number of layers • Layers are slices from .01mm to .7 mm (technique)

The Slice • Auxiliary Structure • Supports the model during build • Useful for delicate parts • Some time difficult to remove • Damage to Model • Poor surface finish

Layer by Layer • Construction of the part • Several Techniques • Builds part one layer at a time • Polymers • Paper • Wax • Powdered Metal

Clean and Finish • Final Step is post-processing • Removing prototype • Detaching supports • Curing (if needed) • Minor Cleaning • Surface treatment • Sanding, sealing, painting and so on

Clean and Finish

Rapid Prototyping Techniques

Laminated Object Manufacturing • Called LOM. (Helisys) • Paper is coated heat-activated glue so it will stick. (spool) • Paper is bonded with last piece with heated rollers. • Design is cut out of paper with a laser. • The excess paper is cross hatched for removal. • Produces large parts. • Wood like texture

LOM Process

LOM Examples

Selective Laser Sintering • Called SLS. (DTM – Carl Deckard) • Melts powdered material a layer at a time. • Uses leveling rollers • Laser is used to melt powdered material. • Traces part and sintering metal powder • Makes functional parts. • Many different powders can be used.

SLS Process

SLS Examples

Stereolithography • Called SLA. (3D Systems –first 1986) • Photosensitive liquid resin hardens when exposed to a laser. • Low-power high focused UV laser • Traces out layer, solidifying resin • Liquid epoxy or acrylate resin • The part is created layer by layer. • The part needs to be cured after it is created. • Great accuracy and surface finish.

SLA Process

SLA Examples

SLA Examples Cont…

Fused Deposition Modeling • Second Most Widely Used • Filament of heated thermoplastic is extruded from the tip • X-Y plane • Like decorating a cake • Platform lowered and head deposits a second layer upon the first • ABS, PC, Casting Wax, Polyphenolsulfone

FDM SAMPLES

Solid Ground Curing • SGC - (Cubical) • Similar to stereolithography • Uses UV light • Selectively hardens photosensitive polymers • Cures entire process at a time • Photomask • Printed on glass plate • UV light passes through the mask to the polymer

SGC

3D Jet Printing • Entire class of machines • 3D Printing (3DP – MIT, Soligen Corp.) • Powder (excess is blown off) • ZCORP 3D (Z corp.) • Powder (excess is blown off) • Thermo-Jet (3D systems) • Molten wax or polymer (no excess) • The model is built up layer upon layer at a time. • Ink-jet printer head technology • Different materials can be used. • Versatile

3D Printing Process

3D Printing Examples

3D Printing Examples Cont…

Source Credit • http://home.att.net/~castleisland/lom_int.htm • http://www.milparts.net/lom.html • http://www.ind.tno.nl/prototyping/rapid_prototyping/lom.html • http://www.bath.ac.uk/~en7bnd/rp/lom.htm • http://home.att.net/~castleisland/sls_int.htm • http://www.materialise.com/mt.asp?mp=ps_laser • http://www.cs.hut.fi/~ado/rp/subsection3_6_3.html

Source Credit Cont. • http://www.cs.hut.fi/~ado/rp/subsection3_6_1.html • http://www.padtinc.com/rm/sla/default.htm • http://www.webworqs.com/nomura/stereo.html • http://www.howstuffworks.com/stereolith3.htm • http://www.nsf.gov/od/lpa/news/02/3dprinttip_images.htm • http://web.mit.edu/tdp/www/whatis3dp.html • http://web.mit.edu/tdp/www/applications.html • http://www.zcorp.com/content/product_info/keyadvantages.html

Rapid Prototyping