Transcript MSE508 Lecture Spring 2008 –Week 4 – I. Costea, Ph.D. Rapid Prototyping and Manufacturing Rapid Prototyping and Manufacturing • Rapid Prototyping Overview • Lab 1128 3D.

MSE508 Lecture Spring 2008
–Week 4 – I. Costea, Ph.D.
Rapid Prototyping and
Manufacturing
Rapid Prototyping and Manufacturing
• Rapid Prototyping Overview
• Lab 1128 3D Systems RP Printer
Rapid Prototyping Overview
• Rapid Prototyping (RP): A one step
process of building a prototype directly
from the geometric model of the part to be
manufactured
• Rapid Prototyping is also known as:
layered manufacturing, 3D printing,
desktop manufacturing, and solid freeform
manufacturing
Solid freeform fabrication (SFF)
• is a technique for manufacturing solid objects by
the sequential delivery of energy and/or material
to specified points in space to produce that solid.
• SFF is sometimes referred to as rapid
prototyping, rapid manufacturing, layered
manufacturing and additive fabrication.
Open Wikipedia page:
http://en.wikipedia.org/wiki/Solid_freeform_fabrication
What is Rapid Prototyping?
Copyright 2005 by Wohlers Associates, Inc
Rapid prototyping is an additive fabrication technology
used for building physical models and prototype parts
from 3D computer-aided design (CAD) and medical scan
data. Unlike CNC machines tools, which are subtractive
in nature, these systems join together liquid, powder, and
sheet materials to form complex parts. Layer by layer,
they fabricate plastic, wood, ceramic, and metal objects
based on thin horizontal cross sections taken from a
computer model.
Open Wohlers’ page:
http://wohlersassociates.com/rapid-prototyping.html
• http://en.wikipedia.org/wiki/Rapid_prototyping
Very good page on RP; has some good references
Rapid Prototyping Overview
• Basic steps in RP (3 steps):
– Form the cross sections of the object
– Lay the cross sections layer by layer
– Combine the layers
• Therefore
– Only cross sectional data is needed for each layer
– Common problems with mold and dies are avoided
Forming dies
are typically made by tool and die makers and put into production after
mounting into a press. The die is a metal block that is used for forming
materials like sheet metal and plastic. For the vacuum forming of plastic
sheet only a single form is used, typically to form transparent plastic
containers (called blister packs) for merchandise. Vacuum forming is
considered a simple molding thermoforming process but uses the same
principles as die forming. For the forming of sheet metal, such as
automobile body parts, two parts may be used, one, called the punch,
performs the stretching, bending, and/or blanking operation, while another
part, called the die block, securely clamps the workpiece and provides
similar, stretching, bending, and/or blanking operation. The workpiece may
pass through several stages using different tools or operations to obtain the
final form. In the case of an automotive component there will usually be a
shearing operation after the main forming is done and then additional
crimping or rolling operations to ensure that all sharp edges are hidden and
to add rigidity to the panel.
From:http://en.wikipedia.org/wiki/Die_(manufacturing)
• See the picture of the bending die press
animated at:
• http://en.wikipedia.org/wiki/Die_(manufact
uring)
Rapid Prototyping Overview
• 3D Printing:
– Developed at MIT
– Similar to inkjet printing
Open: http://en.wikipedia.org/wiki/3D_Printing
• General process steps:
– Ceramic powder is deposited to the proper thickness
– Powder is selectively scanned with a liquid binder
– See Figure next slide
Fig. 12.6 p. 386
Rapid Prototyping Overview
•
Stereo Lithography Apparatus (SLA):
– Development by 3 people: A. Herbert of 3M Corporation in Minneapolis, an H.
Kodame of Nagoya Prefecture Research Institute, Japan (stopped because of
lack of financial support)
– C. Hull of UVP Ultra Violet Products in California completed development starting
3D Systems in 1986 coining the term “stereo lithography”
•
General process steps:
– Photosensitive polymer held in a liquid state
– UV laser scans the profile and solidifies the liquid to form the bottom edge of the
part
– A platform is lowered as each layer is created
– Post curing to finish part
Open: http://www.efunda.com/processes/rapid_prototyping/sla.cfm
(very good explanation of SLA with pictures)
Rapid Prototyping Overview
• Solid Ground Curing (SGC) called also Solider Process
– More accurate than SLA
– Needs no support structure for large voids
– Each layer is cured by a UV lamps… no UV laser
• General process steps:
–
–
–
–
–
–
Platform covered with thin layer of liquid photopolymer
Optical mask positioned and UV lamp exposes polymer
Residual liquid is wiped away
Layer of wax fills voids and is solidified by a cold plate
Layer is trimmed by a mill to desired height
Process repeated and wax is melted away on completion
Open: http://www.efunda.com/processes/rapid_prototyping/sgc.cfm
Very good introduction (with pictures) of SGC
See Figure 12.4 p. 385
Rapid Prototyping Overview
• Selective Laser Sintering (SLS):
– Developed by DTM in the United States
– Any meltable powder may be used if laser strong enough
• General process steps:
–
–
–
–
Chamber is heated to aid in laser sintering
Powdered material is applied from feed cylinder
Powder is selectively heated with a laser causing binding
The part cylinder is lowered and a new layer of powder is rolled
and heated
– Upon completion unused material is simply brushed away
– See Figure next slide
http://en.wikipedia.org/wiki/Selective_laser_sintering
• Picture 12.X for previous text slide
Rapid Prototyping Overview
• Laminated-Object Manufacturing (LOM):
– Commercialized by Helisys, Inc.
– Laser trims material in sheet form one sheet at a time
• General process steps:
– A sheet attached to the block from a material supply rol then is
laminated with a heated roller
– A laser trims the profile … only the edges are scanned
– The unused areas are sliced into pieces
– The part is now broken into pieces with the resulting part to be revealed
– The final part may be sealed to keep out moisture
http://www.efunda.com/processes/rapid_prototyping/lom.cfm
Very nice intro with picture
LOM
– See Figure 12.7, 12.8
Rapid Prototyping Overview
• Fused-Deposition Modeling (FDM):
– Commercialized by Stratasys, Inc.
http://www.stratasys.com
– It’s an additive process
– Layers generated by extruding thermoplastic material
– Analogous to depositing chocolate cream on a cake
• General Process steps:
– Thermoplastic material is deposited on the table just
above solidification temperature
– The table or head moves to create the next layer
FDM
– See Figure 12.9
http://www.stratasys.com/media.aspx?id=76
Rapid Manufacturing at BMW: Rapid Manufacturing
Jigs and Fixtures with FDM
• Read about BMW use of Stratasys
– The plant’s department of jigs and fixtures uses FDM to build hand-tools
for automobile assembly and testing
– Rapid prototyping has become a standard practice in product
development. At the BMW AG plant in Regensburg, Germany, FDM
(fused deposition modeling) continues to be an important component in
vehicle design prototyping. But moving beyond prototyping, BMW is
extending the application of FDM to other areas and functions, including
rapid manufacturing.
– FDM to make ergonomically designed assembly aids that perform better
than conventionally made tools; FDM process can be an alternative to
the conventional metal-cutting manufacturing methods like milling,
turning, and boring
• and look at several other case studies
http://www.stratasys.com/fdm_materials.aspx?id=729
• Stratasys FDM systems use a variety of production-grade
thermoplastics, including ABS, PC (polycarbonates), PPSF
(polyphenylsulfones) and blends to manufacture Real Parts TM .
Because Real Parts from a Stratasys FDM system are composed of
production thermoplastics, your parts will more closely predict endproduct performance. These materials allow you to manufacture
Real Parts that are tough enough for functional testing, installation,
and most importantly — end use.
Real production thermoplastics are stable and have no appreciable
warpage, shrinkage or moisture absorption, like the resins (and
powders) in competitive processes. Because thermoplastics are
environmentally stable, part accuracy (or tolerance) doesn’t change
with ambient conditions or time. This enables FDM parts to be
among the most dimensionally accurate.
FDM Material Guide
http://www.stratasys.com/fdm_materials.aspx?id=729
Stratasys FDM advantages
in BWM case study
•
Enhance the ergonomics of hand-held assembly devices used in the plant - to improve
productivity, worker comfort, ease-of-use, and process repeatability
The freedom of design allows engineers to create configurations that improve handling, reduce
weight, and improve balance.
Example: The tool designs created with FDM often cannot be matched by machined or molded
parts. In one example, BMW reduced the weight of a device by 72 percent with a sparse-fill build
technique. Replacing the solid core with internal ribs cut 1.3 kg (2.9 lbs) from the device. This may
not seem like much, but when a worker uses the tool hundreds of times in a shift, it makes a big
difference.
•
Improved functionality
Since the additive process can easily produce organic shapes that sweep and flow, the tool
designers can maximize performance while improving ergonomic and handling characteristics.
The layered FDM manufacturing process is well suited for the production of complex bodies that,
when using conventional metal-cutting processes, would be very difficult and costly to produce.
An example is a tool created for attaching bumper supports, which features a convoluted tube that
bends around obstructions and places fixturing magnets exactly where needed.
BMW case study
• FDM is taking on increasing importance as an
alternative manufacturing method for
components made in small numbers
• the jigs and fixtures department has developed a
simple flow chart to determine when FDM is a
fitting option. The criteria are temperature,
chemical exposure, precision, and mechanical
load. With FDM’s ABS material, which the
engineers find comparable to polyamide (PA 6),
many tools for vehicle assembly satisfy the
criteria.
Applications to Design
• Rapid Tooling (RT): Quickly creating tools for manufacturing
http://www.efunda.com/processes/rapid_prototyping/rt.cfm
Very good intro – open page
• RT has 4 distinct types:
• Direct tooling: Tools are made directly from RP process, Figure
12.12
• Single-reverse tooling: Investment casting, sand casting, spray
metal casting, and silicon RTV rubber molds. Converts different RP
patterns into castings with other materials, Figure 12.14
• Double-reverse tooling: Combines single reverse and double
reverse process often using a plaster mold. Figure 12.21
Applications to Manufacturing
• Prototyping for Design Evaluation
• Prototyping for Function Verification
• Modeling for further manufacturing
processes
Rapid Prototyping Overview
Source:
CAD/CAM Principles, Practice and
Manufacturing, 2nd Edition by Chris
McMahon, and Jimmie Browne. Addison
Wesley Longman Limited 1996, pp. 3-13
http://www.tagrimm.com/benchmarks/download_exec_1005.html
• In an evaluation of
rapid prototyping
systems, please rate
the following in
order of importance
(e.g. 1 being the
most important, 12
the least important)
Material selection:
Ease of use:
Surface finish:
Dimensional accuracy:
Material cost:
Feature resolution:
Complex geometry:
Process speed:
Minimal post
processing:
Office compatibility:
Initial purchase price:
Maintenance expense:
Predictions for RP for 2008
http://www.deskeng.com/articles/aaagtb.htm
•
•
•
•
Direct Digital Manufacturing (DDM)
Low cost RP systems
Materials
Economy
– Less service bureaus
– physical prototyping replaced by
http://www.deskeng.com/articles/aaagtb.htm
T. A. Grimm & Associates in Edgewood, Kentucky, an independent consulting firm
Direct Digital Manufacturing (DDM)
“DDM is still new and very immature with
respect to technology adoption, but it’s
getting some traction and people are
starting to take it seriously,” said Grimm.
“We might see some interesting DDM
developments in 2008.”
Predictions for RP for 2008
http://www.deskeng.com/articles/aaagtb.htm
• nothing that promises to be earth shattering
• from prototyping to manufacturing to low end
printers to high end systems, from plastics to
metals
• commercialization of two low cost systems in
early 2008 - one from 3D Systems and one from
Desktop Factory, both promised at below
$10,000
Todd Grimm
Predictions for RP 2008
• 2007 ushered in new classes of materials with
some big advances.
• announcement of Objet’s new Digital Materials,
which he has written about for DE (see Special
RP&M section, February 2008, p. 50). “The
technology allows you to take two of their
photopolymers and combine them on the fly to
make a unique third material, which means you
can make a single part with multiple material
characteristics, not previously available in the
plastics world.”
http://www.designnews.com/article/CA6524502.html
•
In December 2007, Objet Geometries announced its new PolyJet Matrix
technology for creating rapid prototype models using multiple materials. The
technology and the Connex500 RP system that uses it made its U.S. debut
on the show floor at SolidWorks World 2008.
•
The system is yet another leap forward for the rapid prototyping industry by
enabling the simultaneous jetting of multiple model materials in a single
build process.
•
The system provides 600 x 600 dpi models in both the x and y axes, with
model walls as little as 0.6mm. The company claims the highly precise
printing delivers 0.3-mm tolerance across large models. There are up to 21
materials to choose from that deliver such features as translucent parts, the
ability to coat parts for a rubber-like appearance and parts with combined
rigid body and flexible material.
•
The machine is 55 x 44 inches wide and 44 inches high.
http://www.tenlinks.com/news/PR/objet/111907_polyjey_matrix.htm
• REHOVOT, Israel, Nov 19, 2007 – Objet
Geometries Ltd., the world leader in jetting ultrathin layers of photopolymer, today announced its
new PolyJet Matrix Technology, the first method
that enables the simultaneous jetting of different
types of model materials.
• This innovation opens up virtually unlimited
opportunities for closely emulating the look, feel
and function of final products, pioneering an
entirely new direction in the 3D printing of
models, prototypes and manufactured parts.
Predictions for RP
Todd Grimm
• If the economy is down and investments in prototypes
and prototyping equipment are impacted, people may
turn to virtual prototyping, such as that which Autodesk
has been promoting.
• If someone feels they need RP during a recession,
obviously they’ll be more likely to consider low cost
systems, and now they’ll have an option below $10K.
• Service bureaus will be affected by downturns in the
market; once down it will take 3 years to go back to the
same use
Applications –
3D printer provides dental models
• 3D Systems' ProJet DP 3000 3D Production
System is a 3D Printer that accurately,
consistently and economically manufactures
precision wax-ups for dental professionals.
The user of the ProJet DP Production System
scans a model, designs a virtual wax-up using
3D software, then sends the data to the ProJet
Production System to 'print' wax-ups in layers.
http://www.engineeringtalk.com/news/dsy/dsy177.html
Applications –
3D printer provides dental models (Ctnd.)
• The system can generate hundreds of units each cycle.
• Built in VisiJet DP 200 Material, the wax-ups have a smooth surface
finish and can be cast or pressed with conventional techniques.
• The specially formulated material for dental applications is virtually
ash-free and can be used with traditional laboratory waxes.
• The printer's large build volume and optional part stacking and
nesting capabilities enable unattended operation, suitable for highvolume production.
• The open architecture allows file transfer from any open scanner on
or off site.
• Current material applications include full cast crowns, bridges,
partial frameworks and full contour units to be pressed over metal
and zirconia copings.
• Other potential applications include the rapid production of surgical
guides and models.
Rapid manufacturing system rivals CNC accuracy
Precision Prototyping (APP) has added a Viper Pro
SLA System to its fleet of
3D Systems' large-part manufacturing systems.
• The Viper Pro SLA System delivers strong parts with high
surface smoothness, feature and edge definition and tolerances,
with accuracy rivaling that of CNC-machined plastic parts.
• This system enables customers to consistently and
economically mass customize and produce high-quality, enduse parts, patterns, wind tunnel models, functional prototypes,
fixtures and tools.
• speed, accuracy, superior surface finish and expanded build
envelope = rapid manufacturing equipment
Nanocomposite material for
Stereolithography
• 3D Systems Corp has developed a new engineered
nanocomposite material
• Designed for motorsport and aerospace applications, Accura
Greystone material delivers exceptional accuracy, stiffness, thermal
performance as well as long-term stability.
• The grey-coloured nanocomposite material was developed for
rigorous, high-pressure wind-tunnel testing, under-the-bonnet
automotive applications and other uses requiring high thermal
resistance, insulating electrical components, and building accurate
and stable jigs and fixtures.
http://www.engineeringtalk.com/news/dsy/dsy174.html