Rapid Prototyping

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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_prototypin
  g/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?mpps_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_image
  s.htm
• http//web.mit.edu/tdp/www/whatis3dp.html
• http//web.mit.edu/tdp/www/applications.html
• http//www.zcorp.com/content/product_info/keyadvan
  tages.html