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7/28/2019 17 - Rapid Prototype
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Ken Youssefi MAE dept, SJSU 1
(RP)
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Ken Youssefi MAE dept, SJSU 2
The design teams should use two methods for
modeling and simulating a products performance.
Physical models (prototype)
Analytical (virtual, digital) models
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Ken Youssefi MAE dept, SJSU 3
Analytical (Digital) models
Computer generated models (3D solid model) are used to
perform finite element analysis (stress, deflection, thermal, ),
drop test, flow analysis, kinematics (motion) analysis andoptimization.
Stress and
deflection
analysis
Thermal analysis
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Ken Youssefi MAE dept, SJSU 4
Analytical (virtual) models
Flow analysisDrop test
Motion andForce analysis
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Ken Youssefi MAE dept, SJSU 5
Analytical (digital) models
Analytical models cannot be expected to produce accurate
results if the underlying physics is not well understood.
A detailed model may require a long development time.
Unexpected phenomena and effects are most likely to be
discovered during the physical prototype testing
Advantages
The analytical model, due to theoretical limitation, may poorly
estimate the actual product behavior.
Disadvantages
Analytical models are more flexible than physical models. It
is much easier to change parameters and to study differentdesign scenarios.
Less expensive than a physical model.
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Ken Youssefi MAE dept, SJSU 6
Physical models
There are two main considerations in the development of a
physical model; Cost and Cycle Time
It is not practical to build a prototype at every level of the
product development stages.
Due to competition, a new product has to enter the
market at a fast pace.
Improvement in solid modeling tools and design philosophy
(concurrent engineering) has reduced considerably the
number of physical prototypes needed to verify designparameters and configurations.
Analytical (digital) model should be used to study the range of
feasible parameters and then the physical model is used to
verify and fine tune the design.
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Ken Youssefi MAE dept, SJSU 7
Physical PrototypeA physical prototype is build for the following reasons:
Verifying and Learning
Does the product work?
Does the product meet the design team
specification and requirements?
Does the product meet the customer needs?
Integration
Prototypes are used to ensure that different
subsystems interface correctly.
Communication
A physical prototype makes it easier for the
management, customers and vendors to visualize
the design and understand its function.
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Ken Youssefi MAE dept, SJSU 8
Prototyping Processes
Through out the years, many different production
processes have been used to create prototypes (cast
metal molds, epoxy molds, silicon rubber molds, injection
molding, CNC machining ..). But in recent years, due tosophisticated computer software (3D parametric
modelers), Material Addition Rapid Prototyping hasemerged as the preferred process for many application.
Material Removal
Casting/Molding
Material Addition
Three major categories
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Rapid Prototyping (Direct Digital Manufacturing)
Ken Youssefi MAE dept, SJSU 9
The popular commercial rapid prototyping processes can
be categorized as: Stereolithography (laser fusion), Fused-Deposition Modeling (FDM), Inkjet printing and Lamination.
Solid freeform fabrication involves constructing a three
dimensional object one cross sectional layer at a time,
depositing a material or by solidifying liquid or hardening
powder. The object is first created using a 3D parametric
modeler (Pro/E, Unigraphics, SolidWorks, ).
RapidPrototyping
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RP Starting Materials
Ken Youssefi MAE dept, SJSU 10
Liquid polymers that are cured layer bylayer into solid polymers (plastics)
Powder that is bonded layer by layer intoa solid
Solid sheets that are laminated to form the
solid part
Solid polymer that is heated (melted) and
deposited layer by layer to form the solid
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Ken Youssefi MAE dept, SJSU 11
Stereolithography (Liquid-Based)
Stereolithography (STL or SLA) was the first RP technology
dating back 25 years.
The process uses photosensitive liquid
polymer as the material.
A laser beam is used to cure (harden) theliquid. The beam hits the liquid according to
the path program generated by the CAD
The laser beam solidifies one layer at a timewhile the platform is lowered by the thickness
of each layer.
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Ken Youssefi MAE dept, SJSU 12
The Stereolithography Process
You create a 3-D 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 3-D printer's laser "paints" one of the layers,
exposing the liquid plastic in the tank and hardening it.
The platform drops down into the tank a fraction of a
millimeter and the laser paints the next layer.
This process repeats, layer by layer, until the model iscomplete. This is not a particularly quick process.
Depending on the part size and number of layers, a typical
run might take six to 12 hours. Runs over several days are
possible for large objects.
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Ken Youssefi MAE dept, SJSU 13
Rapid Prototyping3D solid model of the object The part is divided into slices
Only 10% of the
slices are shown
Part is made onelayer at a time
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Ken Youssefi MAE dept, SJSU 14
Prototyping ProcessesStereolithography
The process is based on hardening a liquid photopolymer into a
specific shape. Smallest tolerance that can be achieved is .0005
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Ken Youssefi MAE dept, SJSU 15
The ultraviolet "oven"
used to cure completed
objects.
The platform at the end of a
print run, shown here with
several identical objects.
The platform in
the tank of
photopolymer at
the beginning of
a print run.
SLA
Video
http://www.youtube.com/watch?v=nwQ5HA8sE-khttp://www.youtube.com/watch?v=nwQ5HA8sE-k7/28/2019 17 - Rapid Prototype
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Ken Youssefi MAE dept, SJSU 16The wrench
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Ken Youssefi MAE dept, SJSU 17
Prototyping Processes
Fused-Deposition Modeling (FDM) starting material is solid
polymer
A thermoplastic filament
is extruded through a
small orifice of a heated
die. Layer thickness is
between .01 to .02 inch,
best achievable
tolerance in vertical
direction, tolerance of
.001 inch is attainable inxy plane.
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FDM
Ken Youssefi MAE dept, SJSU 18The jet plane
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mechanism
Ken Youssefi MAE dept, SJSU 19
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uPrint machine
Ken Youssefi MAE dept, SJSU 20
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Affordable 3D printer (ABS)
Ken Youssefi MAE dept, SJSU 21
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Ken Youssefi MAE dept, SJSU 22
Prototyping Processes - ZPrint
Binder
Powder
storage
Roller spreads
a layer of
powder material
Feed Build
Standard inkjetprinthead
Piston lowersmaking room for
new layer
Color
printer
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Inkjet Printing (powder 650 model)
Ken Youssefi MAE dept, SJSU 23
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Working wrench
Ken Youssefi MAE dept, SJSU 24
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Ken Youssefi MAE dept, SJSU 25
ZPrint - examples
Concept Modeling
Size: 21 x 33 x 20 cm
Printing Time: 12 hours
Consumer Products
Size: 8 x 18 x 5 cmPrinting Time: 2 hours
Medical
Size: 25 x 20 x 10 cm
Printing Time: 5.5 hours
Footwear
Size: 10 x 30 x 5 cm
Printing Time: 3 hours
AutomotiveSize: 25 x 28 x 11 cm
Printing Time: 8 hours
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Ken Youssefi MAE dept, SJSU 26
http://money.cnn.com/video/technology/201
1/01/21/t_tt_3d_food_printer.cnnmoney/
3D dessert printer
http://ccinsider.comedycentral.com/2011/08/04
/3d-printer-creates-stephen-colbert-bust/
3D model of Steven Colbert
http://www.pcworld.com/article/229927/makerbot_3d_prints_
stephen_colberts_head_stephen_has_wings_and_tentacles
who_knew.html
http://money.cnn.com/video/technology/2011/01/21/t_tt_3d_food_printer.cnnmoney/http://money.cnn.com/video/technology/2011/01/21/t_tt_3d_food_printer.cnnmoney/http://ccinsider.comedycentral.com/2011/08/04/3d-printer-creates-stephen-colbert-bust/http://ccinsider.comedycentral.com/2011/08/04/3d-printer-creates-stephen-colbert-bust/http://www.pcworld.com/article/229927/makerbot_3d_prints_stephen_colberts_head_stephen_has_wings_and_tentacleswho_knew.htmlhttp://www.pcworld.com/article/229927/makerbot_3d_prints_stephen_colberts_head_stephen_has_wings_and_tentacleswho_knew.htmlhttp://www.pcworld.com/article/229927/makerbot_3d_prints_stephen_colberts_head_stephen_has_wings_and_tentacleswho_knew.htmlhttp://www.pcworld.com/article/229927/makerbot_3d_prints_stephen_colberts_head_stephen_has_wings_and_tentacleswho_knew.htmlhttp://www.pcworld.com/article/229927/makerbot_3d_prints_stephen_colberts_head_stephen_has_wings_and_tentacleswho_knew.htmlhttp://www.pcworld.com/article/229927/makerbot_3d_prints_stephen_colberts_head_stephen_has_wings_and_tentacleswho_knew.htmlhttp://ccinsider.comedycentral.com/2011/08/04/3d-printer-creates-stephen-colbert-bust/http://ccinsider.comedycentral.com/2011/08/04/3d-printer-creates-stephen-colbert-bust/http://ccinsider.comedycentral.com/2011/08/04/3d-printer-creates-stephen-colbert-bust/http://ccinsider.comedycentral.com/2011/08/04/3d-printer-creates-stephen-colbert-bust/http://ccinsider.comedycentral.com/2011/08/04/3d-printer-creates-stephen-colbert-bust/http://ccinsider.comedycentral.com/2011/08/04/3d-printer-creates-stephen-colbert-bust/http://ccinsider.comedycentral.com/2011/08/04/3d-printer-creates-stephen-colbert-bust/http://ccinsider.comedycentral.com/2011/08/04/3d-printer-creates-stephen-colbert-bust/http://ccinsider.comedycentral.com/2011/08/04/3d-printer-creates-stephen-colbert-bust/http://ccinsider.comedycentral.com/2011/08/04/3d-printer-creates-stephen-colbert-bust/http://ccinsider.comedycentral.com/2011/08/04/3d-printer-creates-stephen-colbert-bust/http://ccinsider.comedycentral.com/2011/08/04/3d-printer-creates-stephen-colbert-bust/http://money.cnn.com/video/technology/2011/01/21/t_tt_3d_food_printer.cnnmoney/http://money.cnn.com/video/technology/2011/01/21/t_tt_3d_food_printer.cnnmoney/7/28/2019 17 - Rapid Prototype
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3D Metal Printing
Ken Youssefi MAE dept, SJSU 27
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Bioprinting Organs The Future
Ken Youssefi MAE dept, SJSU 28