Rapid Prototyping Laminated Object Manufacturing Selective Laser Sintering Stereolithography Fused Deposition Modeling Solid Ground Curing 3 D Printing 1
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 2
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 3
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 4
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 5
Conversion to STL 6
The Slice • Pre-processing program – Prepares STL file for build – Most program allows user to adjust the model • Size • Location • Orientation 7
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. 01 mm to. 7 mm (technique) 8
The Slice • Auxiliary Structure – Supports the model during build – Useful for delicate parts – Some time difficult to remove • Damage to Model • Poor surface finish 9
Layer by Layer • Construction of the part – Several Techniques – Builds part one layer at a time • • Polymers Paper Wax Powdered Metal 10
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 11
Clean and Finish 12
Rapid Prototyping Techniques 13
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 of paper with a laser. • The excess paper is cross hatched for removal. • Produces large parts. – Wood like texture 14
LOM Process 15
LOM Examples 16
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. 17
SLS Process 18
SLS Examples 19
Stereolithography • Called SLA. (3 D 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. 20
SLA Process 21
SLA Examples 22
SLA Examples Cont… 23
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 24
FDM SAMPLES 25
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 26
SGC 27
3 D Jet Printing • Entire class of machines – 3 D Printing (3 DP – MIT, Soligen Corp. ) • Powder (excess is blown off) – ZCORP 3 D (Z corp. ) • Powder (excess is blown off) – Thermo-Jet (3 D 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 28
3 D Printing Process 29
3 D Printing Examples 30
3 D Printing Examples Cont… 31
3 D Printing Examples Cont… 32
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. h tml • http: //www. bath. ac. uk/~en 7 bnd/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/subsection 3_6_3. html 33
Source Credit Cont. • • http: //www. cs. hut. fi/~ado/rp/subsection 3_6_1. html http: //www. padtinc. com/rm/sla/default. htm http: //www. webworqs. com/nomura/stereo. html http: //www. howstuffworks. com/stereolith 3. htm http: //www. nsf. gov/od/lpa/news/02/3 dprinttip_images. htm http: //web. mit. edu/tdp/www/whatis 3 dp. html http: //web. mit. edu/tdp/www/applications. html http: //www. zcorp. com/content/product_info/keyadvantages. html 34
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