Transcript Document 7173115

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Layered Solidification Processes
Liquid-Based Approaches
 Stereolithography
Powder-Bed Based Approaches
 3D
Printing (Z-Corporation)
 Selective
Laser Sintering
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Stereolithography (SLA)

First commercial layered
manufacturing technology (1988)

Photo-curable liquid resin

www.3dsystems.com
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SFF: Stereolithography (SLA)

UV laser beam solidifies the top layer
of a photosensitive liquid.
UV Laser Beam
Photopolymer
Build Stage
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Stereolithography: Principle
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Stereolithography
Pre-process:
 Orient
part.
 Choose
 Slice
slice thickness.
parts and plan supports.
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Stereolithography
Process:
 Position
build platform (stage)
just below liquid resin surface.
 Smooth
surface with re-coater blade.
 Scan
the outline of the current slice,
loosely hatch part interior with laser.
 Lower
the build platform for next layer.
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Stereolithography
Post-process:
 Raise

part and drain out liquid.
(except liquid trapped by loose hatch)
 Break
off supports.
 Rinse
in isopropanol and water.
 Dry
with air hose.
 Post-cure
(strengthen) in UV oven.
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Stereolithography
Characteristics:

Slow process

Supports must be removed by hand

Lab environment necessary (gasses!)

Needs trained operator

Laser lasts 2000hrs, costs $20’000!

Little material choice, ($700 per gallon)

Parts can be brittle, fragile
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Stereolithography
Characteristics (cont.):


High accuracy

Layer thickness 0.001 - 0.006”

Minimum feature size 0.003 - 0.012”
Large build volume

Up to 20 x 20 x 23”
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Powder-based Approaches
Key Properties:
 Needs
no supports that must be removed!
 Uniform
 This
bed of powder acts as support.
powder gets selectively (locally)
glued (or fused) together to create the
solid portions of the desired part.
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SFF: 3D Printing -- Principle

Selectively deposit binder droplets onto a
bed of powder to form locally solid parts.
Head
Powder Spreading
Printing
Powder
Feeder
Build
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3D Printing: Some Key Players
Z
Corporation: http://www.zcorp.com/
Plaster and starch powders
for visualization models.
 Soligen:
http://www.zcorp.com/
Metal and ceramic powders
for operational prototypes.
 Therics
Inc.: http://www.therics.com/
Biopharmaceutical products,
tissue engineering.
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3D Printing: Z Corporation
The Z402 3D Printer

Speed: 1-2 vertical inches per hour

Build Volume: 8" x 10" x 8"

Thickness: 3 to 10 mils, selectable
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3D Printing: Z Corporation
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3D Printing: Z Corporation
 Digging
out
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Optional Curing: 30 min. @ 200ºF
Keep some powder in place
<-- Tray for
transport
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3D Printing: Z Corporation
Cleaning up in the de-powdering station
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3D Printing: Z Corporation
The finished part
 Zcorp,
 6"
6
diam.,
hrs.
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120 Cell -- Close-up
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Parallel Projection of the 4D 120-Cell
 Zcorp,
 6"
6
diam.,
hrs.
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Morin Surface
3D-Print
6" diam.
5 hrs.
This is the half-way point of a sphere eversion
(without causing creases or tears).
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3D Color Printing: Z Corporation
The Z402C 3D Color Printer
Differences compared to mono-color printer:

Color print head with: Cyan, Yellow, Magenta,
Black, and Neutral.

Smaller build area.
Specs:

Speed: 0.33 - 0.66 vertical inches per hour

Build Volume: 6" x 6" x 6"

Layer Thickness: 3 to 10 mils, selectable

Color depth: 80 mils below surface
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3D Color Printing: Z Corporation
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3D Color Printing: Z Corporation
Use compressed
air to blow out
central hollow
space.
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3D Color Printing: Z Corporation
Infiltrate Alkyl Cyanoacrylane Ester = “super-glue”
to harden parts and to intensify colors.
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3D Color Printing: Z Corporation
“Lizard-Frame”: Final Infiltrated Part
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Hypercube, Perspective Projections
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Two Ways to Make a Hypercube
3D Color Print
Assembly of
flat FDM parts ==>
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What Can Go Wrong ?
-- Parts may brake before infiltration
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What Else Can Go Wrong ?

Blocked glue lines

Crumbling parts
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Post-Processing for 3D-Printing
Surface is porous, dusty.
 seal and strengthen the part:
 Dip
in wax:

Nice smooth finish

Needs separate waxing station
 Infiltrate

with “superglue”:
Tedious, dirty manual labor
 Spray-paint
with a sealant:

Polyurethane (yellowish, smelly)

Krylon (invisible)
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Post-Processing for 3D-Printing
 Spray-paint
surface with Krylon
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3D Printing: Z Corporation
An Informal Evaluation
 Fast
!
 Running
expenses: moderate,
(but overpriced powder)
 Color
print head and tubes need
some care in maintenance.
 Somewhat
 Lot’s
messy cleanup !
of dust everywhere ...
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Selective Laser Sintering (SLS)
Key Points:
 Powder
gets solidified with a laser.
 Powder
is kept just below melting point,
heat from laser will fuse powder grains.
 Un-fused
powder acts as support,
can easily be removed later.
 Many
different materials can be used
when mixed with a suitable binder:
nylon, metal, ceramics …
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SLS: Conceptual View
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SLS Players
3D SYSTEMS

Representing the fourth generation of SLS®
(selective laser sintering) technology,
Vanguard™ and Vanguard™ HS (High Speed),
are the first SLS® systems developed specifically
for advanced manufacturing applications.

With the Vanguard system you can move directly
from a CAD file to a durable, functional plastic or
metal part or tool — in a fraction of the time
required for traditional machining and tooling.
http://www.3dsystems.com/products/sls/vanguard/index.asp
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SLS from 3D SYSTEMS
Use
•
•
•
•
•
Vanguard or Vanguard HS system for:
Plastic or metal parts, patterns & prototypes
Complex metal tooling inserts
Highly Durable Parts
Parts with small features
Short runs of plastic & metal parts
Benefits:
• High part accuracy
• Fast build speed
• Unattended operation
• Uses plastic or metal materials
• Respond to customer demands
• Worldwide service and support
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SLS: Laserform Parts
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The Most Challenging SFF Part
3rd-order 3D Hilbert Curve:

much weight

much length

no supports

only two tubeconnections
between the
two halves.
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Fabricated by ProMetal
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ProMetal Process
A
‘green’ part is first formed,
composed of stainless steel powder
and a selectively applied binder.
 This
part is built bottom-up, layer-by-layer
under direct computer control.
 This
green part is then sintered,
the binder is drained out
and replaced by liquid bronze.
 ProMetal
is a division of
‘The Ex One Company’, Irwin, PA.
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Which Process Should You Pick?
Do you need a prototype (not just a model)?
 SLS, FDM (for robustness, strength).
Do you need a mold for a small batch?
 SLA (for smooth, hard surface).
Does part need multiple colors?
 3D Color-Printing.
Does part have convoluted internal spaces?
 3D-Print, SLS, SLA (easy support removal).
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Informal Process Ratings Matrix
Hollow
Hollow
2 Nested,
Sphere Sphere with Perforated
Drain/Vent Spheres
3D
Hilbert
Pipe
Preassembled
Gear
Mechanism
LOM
(F)
F
F
D
F
SLA
FDM
3D-P
SLS
(F)
(F)
(F)
(F)
D
F
A
A
C
C
A
A
B
C
C
B
D
D
B
B