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Rapid Prototyping

Laminated Object Manufacturing

Selective Laser Sintering

Stereolithography

Fused Deposition Modeling

Solid Ground Curing

3D Printing

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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

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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

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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

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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

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Conversion to STL

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The Slice

• Pre-processing program– Prepares STL file for build– Most program allows user to adjust the model

• Size

• Location

• Orientation

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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)

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The Slice

• Auxiliary Structure– Supports the model during build– Useful for delicate parts– Some time difficult to remove

• Damage to Model

• Poor surface finish

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Layer by Layer

• Construction of the part– Several Techniques– Builds part one layer at a time

• Polymers

• Paper

• Wax

• Powdered Metal

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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

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Clean and Finish

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Rapid Prototyping Techniques

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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

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LOM Process

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LOM Examples

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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.

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SLS Process

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SLS Examples

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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.

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SLA Process

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SLA Examples

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SLA Examples Cont…

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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

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FDM SAMPLES

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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

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SGC

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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

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3D Printing Process

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3D Printing Examples

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3D Printing Examples Cont…

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3D Printing Examples Cont…

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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

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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