Rapid Prototyping New Technologies for the Classroom

Rapid PrototypingRapid Prototyping

New Technologies for the New Technologies for the ClassroomClassroom

What is Rapid Prototyping?

� A set of processes that allows a concept or idea to be turned into a three-dimensional physical object, usually in a matter of hours or days, rather than weeks or months.

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weeks or months.

� A technology with wide applicability in product design, manufacturing, sales/marketing, advertising and education.


� Unlike machining methods that are subtractive wherematerial is removed to produce the desired shape





� Rapid Prototyping processes are additive – objects are built from a 3-dimensional computer model in layers, built from a 3-dimensional computer model in layers, without molds, forms, or machining.


Rapid Prototyping at MSOE?

� 1989 — began with an NSF grant application to partially fund the purchase of first SLA machine

� 1991 — formed RP Consortium with four charter members: Outboard Marine Corporation (now BRP), Kohler


Outboard Marine Corporation (now BRP), Kohler Company, Snap-on Tools and Harley-Davidson

� 1994 to 2003 — purchased a LOM machine, an FDM unit, a DTM Sinterstation , an SLA-5000, and another FDM machine, the only university in the U.S. with all these capabilities

� 2008 — moved into a larger RP lab with a total of 10 machines utilizing 15 different materials

Who is the Rapid Prototyping Consortium?


� Reduces engineering changes

� Costs increase as the design moves from concept to product:

Why does RP have value?

$1,000,000


$1

$10

$100

$1,000

$10,000

$100,000

$1,000,000

Conceptual

Design

Detail Design Prototype Tooling Production Field Service

Fail early to succeed sooner.

What is common to all RP processes?

� Construct solid model on any CAD system.

� Translate model to a surface representation: .stl file format is common to all RP machines.

� Generate 2-D slices with path definitions using RP


� Generate 2-D slices with path definitions using RP machine-specific or third-party software.

� Build object.

� Post-process the part.

� Provide the expected finish.

What are current RP processes?

� Stereolithography (SLA)Transparent/translucent parts with good surface finish

� Selective Laser Sintering (SLS)


� Selective Laser Sintering (SLS)Good strength, thermal stability and chemical resistance

� Fused Deposition Modeling (FDM)Similar to injection-molded ABS, polycarbonate or sulfones

� 3-Dimensional Printing (3DP)Most are fast — great for concept evaluation

Stereolithography


Stereolithography

1- laser

2- mirror


2- mirror

3- positioning mechanism

4- liquid polymer with photoinitiator

5- part

Stereolithography

Minimal FinishingFinished and Lacquered


Selective Laser Sintering



1- laser

2- mirror

3- roller


3- roller

4- powder

5- powder chamber

6- process chamber

7- part


Use of glass-filled SLS provides

higher stiffness (2-3X) with


higher stiffness (2-3X) with

essentially the same surface finish

as unfilled nylon polyamide

Fused Deposition Modeling



1- material spool

2- heated


2- heated extrusion head

3- part

4- platform



Polyphenylsulfone (PPSF)

Concept Modeling Machines (3DP)

� Known by various trade names

� Multi-Jet Modeling, PolyJet printing or generically as 3-Dimensional printing (3DP)


3-Dimensional printing (3DP)

� Uses thermoplastic polymers (ABS), photopolymers (acrylates), starch or plaster

� Characterized by high production speed and ease of operation

Concept Modeling Machines

� Relatively low acquisition costs

� Operating costs can be higher than anticipated

Most have poor dimensional accuracy and mechanical


� Most have poor dimensional accuracy and mechanical strength compared to other RP processes

3-Dimensional Printing (Z Corp®)


Pros/Cons of Common RP Processes

Stereolithography Selective Laser Sintering


3-Dimensional Printing

Technology in widest use Widest range of available RP materials (including metals)

Relatively low cost systems Low acquisition costs; higher than expected material costs

Transparent/translucent parts with good surface

Multiple parts can be stacked within each build

Compatible with office environments

Most are fast — great for concept evaluation

Highest accuracy High strength with good thermal stability and chemical resistance

Similar properties to injection-molded ABS, polycarbonate or sulfones

Fair-to-poor strength and impact resistance


Build volume as large as 20” x 20” x 23”

Build volume: 14.5” x 12.5” x 17.5”

Build volume: 16” x 14” x 16” Smaller build volumes: usually about 12” x 10” x 8” (varies)

Limited strength and flexibility for some resins

Can be used for tooling or direct manufacturing

Slower than competing RP processes

Easy to use and operate

Can be a slow process for thick-walled parts

Surface finish not as smooth as SLA parts

Poor surface finish due to large slice thickness

Relatively poor accuracy

Largest number of alternative materials and sources

High material and initial equipment costs

Porosity may be a concern Limited choice of materials

Not resistant to high temp or chemical exposure

Most complex machine of all RP processes

Lacks the strength of similar injection molded plastic part

Limited use as a functional prototype (except for Objet)

How does the PLTW partnership work?

� PLTW-Wisconsin will join the Consortium as of January 1, 2011 and will have a block of RP build hours

� Schools eligible to participate can send student part files on an as-needed basis


� Schools eligible to participate can send student part files on an as-needed basis

� No need for paperwork or Purchase Orders

� Part files and cost quotes are exchanged electronically

� Turn-around time is typically 2-3 days after receipt of the approved part file

How does the PLTW partnership work?

� No charges for shipping of parts

� Teachers and students participating in the program can attend regular RPC meetings at no additional cost


regular RPC meetings at no additional cost

� Teachers and students get access to MSOE research and technical assistance from RPC staff

� Contact Steve Salter, PTLW-Wisconsin Director, for more details on the program

Rapid Prototyping New Technologies for the Classroom

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