Processing of Carbon Fiber Composites for High Volume Mark Voss

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1 Processing of Carbon Fiber Composites for High Volume Mark Voss Engineering Group Manager: Body Structures Advanced Technology Work General Motors Company

2 CF Technology: History Technology has come a long way Back in 2002: Limited Supply Base, Processes, and Technology Development

3 Vehicle Lightweighting Global CO 2 / Fuel Economy requirements will necessitate significant vehicle lightweighting. Expect 1-2 TWC reduction in mass for most vehicles. Lightweight materials will play a significant role in enabling mass reduction.

4 Lightweighting Strategy Efficient Fundamentals Premium Matls & Mfg Processes Cost Up (Applied Independent of Material type to Minimize Mass & Cost) CFRP + Aluminum + Magnesium PHS + Aluminum AHSS/UHSS/PHS Baseline 0% 5% 10% 20% 30% 40% Cost Down Customer Requirements Right Sizing Material Selection Material Utilization Percent Below Industry Regression Line Changes in Requirements are driving Changes in Material Choice

5 What is High Volume? Application Specific Answers Answers depend on.

6 Carbon Fiber Materials New materials and processes are being developed every day Lexus LFA 3D weaving Exponential growth of material and molding process diversification Competitive marketplace Customized solutions

7 What Enables High Volumes? No Single Answer Explore a series of trade-offs that lead down different paths On vehicle cost Supply base is addressing several enablers to higher volumes

8 Thermoset VS Thermoplastics Strength to weight ratio Molding cycle time Hydroscopic, CLTE, TG Recyclability Cost

9 Chopped Fiber VS Continuous fiber Material properties: strength and stiffness Laminated construction vs isotropy Part Manufacturing Part Engineering Preform and molding processes Material availability: supply base Surface finish

10 Material Properties Why Carbon Fiber? Specific Strength (σ/ρ, Mpa) 1000 Various CFRP s Random Mat 35% DFP Uni-Directional Mat 40% Biaxial Pre-Preg 0/90 RTM Uni-Directional Pre-Preg 100 CF-SMC 6xxx AL 5xxx AL PHS Martensite Steel DP Steel HSLA Steel Bake-Hardenable Steel Mild Steel Various Metallics Specific Modulus (E/ρ, GPa)

11 Molding Process Cycle time: quicker is better Economy of scale issues: capital investment Energy usage Any required pre or post operations?

12 Part Integration Impacts The part is not the only aspect of high volume applications Joining Assembly Dimensional repeatability Carbon Glass Hybrid Nano Composite Glass Pre-form Nano Composite Glass Pre-form Composite with Foam Core

13 Composite Joining Technologies Bonding Panel Bonding Summary: Structural Urethane Adhesive; Tub, Surround, Whl Hse: 66 meters (216 feet) Urethane; Dash and Door Ring: 11 meters (36 feet) Seam Sealer; 11 meters (36 feet) Total adhesive and sealer per vehicle (including frame) = 135 meters (443 ft) adhesive bond paths - 26 robots apply ~135 meters (443 feet) of adhesive and sealer

14 Costs Tied to Vehicle Integration For Example: Joint selection alone can drive NVH issues resulting in additional acoustical treatments Spot Welds Laser Welds Adhesive Net cost of the selected materials needs to encompass a total vehicle perspective Load pathing will dictate part construction

15 Class A Surface The primary cost driver Part finishing and painting costs can exceed all other component cost inputs Doubles the part costs EVERYTHING impacts the surface finish

16 Painting of Carbon Fiber Painted on skuks Heat impacts to surface quality: Porosity

17 Recycling & Sustainability In process material scrap End Of Vehicle Life Many countries have adopted or are looking into and adopting ELV laws Include requirements for vehicle recyclability at Type Approval and for takeback/recycling of the vehicle by the OEM at end of life Ex: Current EU ELV Directive: o 85% reuse/recovery, 80% reuse/recycling by 2005 o 95% reuse/recovery, 85% reuse/recycling by 2015 Regrind and recycling impact on material properties

18 Composite Materials Summary Strategic Application Bang for the Buck Long Term Vision Efficient Design (Efficient Fundamentals) ^2 Cost Effective Integration and Execution Entire Vehicle & Lifecycle Costs Manufacturing Enabled Minimal Impact to BOP