A Novel Approach to Improving Cost-Effective Production of Advanced Composite Structures in High Volume Presented at the 4th Annual Society of Plastics Engineers Automotive Composites Conference 14 September 2004
David Cramer Vice President
[email protected] (970) 945-9377 x122 © 2004 Fiberforge, Inc.
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Fiberforge »
Our Focus >
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Our Goal >
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Developing the most cost-effective manufacturing solutions for advanced composite structures produced in high volume
Bodies-in-Black™ in high volume
History >
Founded in 1999
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Initial work focused on lightweight vehicle design
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Since 2002, the Company has focused exclusively on the development and commercialization of its composite manufacturing technology
© 2004 Fiberforge, Inc.
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Numerous hurdles face advanced composites for automotive applications
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Raw materials cost
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Volatility of price and availability of carbon fiber
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Availability of proven high-volume capable processing techniques
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Predictive engineering capabilities for processing and failure
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Design know-how and industry familiarity
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Standards
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Etc.
© 2004 Fiberforge, Inc.
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Advanced composites in automobiles »
Semi-structural applications abound >
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Advantages of part integration, light weight, system cost savings, design flexibility, improved mechanical performance
Currently, advanced composites are used by “innovators” and “early adopters” for niche applications >
Superior performance (stiffness, light weight)
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High material cost and processing cost
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Building familiarity with materials among engineers and customers
Industry must build on those successes, expanded niches with new approaches to processing that are designed for higher volumes without sacrificing the performance benefits inherent in the material
© 2004 Fiberforge, Inc.
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What is the Fiberforge Process? »
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Thermoplastic composite sheet forming process that uses “tailored blanks” >
Step 1: Automated lay-up of tailored blank
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Step 2: Consolidation of tailored blank
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Step 3: Thermoplastic stamping
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Step 4: Trim
Targets main cost and performance drivers >
Materials cost >
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Manufacturing cost >
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High material throughput during creation of tailored blank, short cycle time for final processing, high levels of automation
Structural performance >
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Raw materials, in-process scrap, efficient use of materials by tailoring the laminate to the load paths in a part
Continuous or long-discontinuous fibers, high fiber volume fraction, tailored orientation
Fiberforge process is flexible >
© 2004 Fiberforge, Inc.
Many reinforcements, thermoplastic matrices, and even thermoset-based composites could be processed 6
Image sources: C2 Composites, Radius Engineering, Cincinnati Machine
What is a tailored blank? »
Flat, semi-consolidated laminate
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Precise fiber orientation in each ply
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Fiber orientation is tailored to part-specific loading
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Multiple fiber types and volume fractions possible within a part
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Shape tailored to part geometry
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Variable thickness
8 plies (1 mm)
10 plies (1.25 mm) 12 plies (1.5 mm)
16 plies (2 mm) © 2004 Fiberforge, Inc.
14 plies (1.75 mm)
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Automated lay-up of a tailored blank »
Starts with raw materials, combining fiber and matrix material in line
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Intermittent lay-up
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Tacks strips of material together
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Rapid material deposition
Fiberforge prototype manufacturing cell
© 2004 Fiberforge, Inc.
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Stamping »
Heat blank in infrared oven
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Shuttle into tool and press
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Close press to form and cool part
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Less than 90-second cycle time
Fiberforge thermoforming press, pictured • 1-m x 1-m working area • 810-mm daylight • 400-ton pressure • 100-kW infrared oven, 60-kW tool heating • Automated blank shuttle system
© 2004 Fiberforge, Inc.
• Air-water mist cooling
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Many process variants are possible » Using various starting materials » High-volume and low-volume equipment configurations of the tailored blank fabrication equipment » Hybrid manufacturing processes (illustrated)
Tailored blank
Stamp blank
© 2004 Fiberforge, Inc.
Source: EPFL
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Performance 1.8 Specific modulus
Specific Modulus (!/")
80
Specific strength
1.6
70
1.4
60
1.2
50
1.0
40
0.8
30
0.6
20
0.4
10
0.2
0
0.0
Specific Strength (#/")
90
l
) ) ) ) m on on ni) MC glass glass PP on ed on b b u l l nu S r r p i y y , 5 a r n n m ca er d d op & & dc 05 ibe pe pe ch fib f Alu onal e 9 n n p p p s o o o o m % p 1 s ti ch ch do arb arb ho 1/ 55 ec Gla n ( ( c c c r i % % a i i x r C 0 0 id % az un Te /6 /3 un SM iber, 50 M qu % w w / n G % 5 f o w n n % 5 t (5 ylo ylo an 55 arb 55% /5 lon e r ( N N C y w g d r e N a y C( rfo Qu ox org M e f p S r b E e n Fi Fib rbo a C St
© 2004 Fiberforge, Inc.
ee
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Starting materials: fibers » Carbon, glass, or other fibers: large-tow fiber possible >
Continuous
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Long-discontinuous fiber
© 2004 Fiberforge, Inc.
Schappe Technique13
Starting materials: matrix » Many factors to consider when choosing matrix >
Fiberforge baseline materials are grades of polyamide
Multi-criteria comparison Cost (weight basis)
Thermal performance worse
ASTM D 4065
Cost (volume basis)
Creep
PA 6/12
90 °C
PC/PBT PA 12
better
Tm
Density
PA 6/12-LT
PA 6/12-LT2
Moisture absorption
Tg
PP PBT PA12 PA6 HDT PA 6/12 PPS
Tensile Strength
Tensile Modulus
© 2004 Fiberforge, Inc.
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Benefits of thermoplastics » Rapid processing >
< 1-min cycle time potential
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Non-reactive during part processing
» Crash energy absorption >
> 2x specific energy absorption compared with thermosets
» More easily recyclable >
LFRT feedstock
© 2004 Fiberforge, Inc.
Image source: DaimlerChrysler AG
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“Graceful” failure of thermoplastic composites
spike
© 2004 Fiberforge, Inc.
soft
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Application case study: Spare wheel well »
Collaborative investigation with Dr. Martyn Wakeman at École Polytechnique Fédérale de Lausane
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Comparison of part cost with several thermoplastic composite starting materials > > > >
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Main cost drivers investigated > > > > > >
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Fiberforge tailored blank (carbon fiber & glass fiber) Thermoplastic prepreg sheet (carbon fiber & glass fiber) Twintex™ GMTex™ Materials, equipment, labor, facilities cost In-process scrap Carbon fiber vs. glass fiber Tailored blank fabrication speed Dedicated vs. utilized manufacturing Production volume
Factors not considered in this analysis > > >
Optimization of tailored blank shape Structural optimization and refinement of laminate architecture Individualized weight savings based on product requirements
© 2004 Fiberforge, Inc.
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Baseline assumptions » General >
Parts produced annually: 20,000, 40,000, and 60,000 parts per year
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Five years of production, 1–3 shifts considered
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Indirect to direct labor ratio 60%
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Interest rate on capital: 7.5%
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Compound reject rate: 2%
» Material prices >
Carbon fiber: $17.25/kg ($7.83/lb)
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Glass fiber: $1.90/kg ($0.86/lb)
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Nylon matrix: $3.52/kg ($1.60/lb)
© 2004 Fiberforge, Inc.
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Spare wheel well design » Part characteristics & assumptions > > > > >
2.5 mm thick 3-kg mass with carbon fiber, 4-kg mass with glass fiber Quasi-isotropic lay-up 50% fiber volume fraction Polyamide matrix
» Baseline mass savings relative to steel > >
50% mass savings for carbon-fiber parts 35% mass savings for glass-fiber parts
» Producible with in-house production equipment
0.83 m
0.23 m
© 2004 Fiberforge, Inc.
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Tailored blank design
0.97 m
1m
35-mm bandwidth scrap = 4%
© 2004 Fiberforge, Inc.
75-mm bandwidth scrap = 8.5%
150-mm bandwidth scrap = 11.7%
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Plant layout for Fiberforge process
© 2004 Fiberforge, Inc.
Image Source: EPFL
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Scrap for preimpregnated sheet
Smallest rectilinear surface—scrap = 16% © 2004 Fiberforge, Inc.
Perimeter blank holder scrap = 33% 25
© 2004 Fiberforge, Inc.
Util, 60k/yr Ded, 60k/yr
Fiberforge GF/PA6-12
Fiberforge CF/PA6-12
Steel
GMCTex
GMTex
GF/PP, 16%
GF/PA6, 16%-rcy
CF/PA12, 16%-rcy
CF/PA66FC, 16%rcy
CF/PA66, 16%-rcy
Cost per part, $ 140 7
120 6
100 5
80 4
60 3
40 2
20 1
0 0
Weight, (kg)
Cost summary
weight, kg
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Next steps in cost analysis »
Investigate overall process economics relative to other processing techniques and materials for specific parts >
Three parts to be chosen that bracket processing potential (hybrid molding, SMC, GMT, sheet thermoforming, steel stamping, aluminum stamping)
Hybrid molding Oriented glassfiber composite © 2004 Fiberforge, Inc.
Primary structure
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Conclusion
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Tailored blanks are cost-competitive with similar starting materials
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Opportunity to further reduce cost by optimizing the fiber lay-up
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Tailored blank technology offers advantages to both glass-fiber and carbon-fiber composites
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Hybrid molding promising; tailored blanks could play a strong role
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Materials cost dominates, but significant opportunities for further cost reduction in processing techniques
© 2004 Fiberforge, Inc.
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