continuing the development of reduced density composites … · continuing the development of...

Continuing the Development of Reduced Density

Composites (SMC) for Automotive Applications

Presentation at SPE ACCE 2011Troy, MI

SPE ACCE 2011 – Troy, MI – September 13, 20110Creative � Reliable � Composites

September 13, 2011

Creative � Reliable � Composites

Terrence J. O’DonovanVP Marketing and Sales

Core Molding Technologies, Inc.

Presented by

Let’s buy a car . . .Let’s buy a car . . .

However, across large populations

worldwide, the following factors almost

Key buying factors depend strongly on individuals’ personal situations when

choosing whether to buy a car, and which model to purchase


worldwide, the following factors almost always appear at the top of the list:

and of all the major consumer buying factors, Safety and Fuel economy are also regulated in the US to meet minimum standards

• Price

• Brand reputation

• Safety

• Fuel economy

• Styling

• Utility (features and benefits)

Improving fuel economy is important to OEMsImproving fuel economy is important to OEMs

The US “Corporate Average

Fuel Economy” (CAFE) defines

the minimum standards for

passenger vehicles

Recently approved increases

to CAFE minimums present

automobile OEMs a steep

challenge in coming years 15

20

25

30

35

40

CAFE

MPG

Average Fuel Economy of New US Passenger Cars

(MPG)


challenge in coming years

The 2016 CAFE targets are

driving an improvement in

fuel economy of at least +20%With targets for 2025even higher

15

1980 1991 1994 1997 2000 2003 2006 2009 2012 2015

Sources: Bureau of Transportation Statistics, EPA.

LightweightingLightweighting works . . . but how much is needed?works . . . but how much is needed?

Reducing vehicle weight improves fuel

economy by reducing inertial forces

acting on the vehicle

Much research work has been done to validate the benefits of reducing weight and to model the impact to fuel economy

from weight reductions


The range of impact is

10%

weightreduction

4-7%

MPGimprovement

To get 20% improvement in fuel economy purely from weight savings would require 30-35%

reduction in weight . . . on 3,800 lb vehicle, that’s a weight reduction of 1,200 lb

Weight reduction

is a

“big time”


“big time”opportunity for the

automotive industry

Start with the “other DStart with the “other DMV”MV” to drive weight savingsto drive weight savings

Not the “Department of Motor Vehicles” but “Density,” “Mass” and “Volume”

density =mass

volume

mass = density x volume

Apply the Principle to the CarThe OEM Perspective

M = D • V

To reduce volume (V):


Save weight by

• Lowering volume

• Lowering density

To reduce volume (V):

• downsize the car

• redesign to eliminate

components

To reduce density (D):

• substitute materials that

have lower densities

COMPOSITES!

Where will the weight reduction come from?Where will the weight reduction come from?

From every

vehicle system . . .

Body

40%

Chassis

24%

Powertrain

16%

Interior

15%

Electrical systems

5%

Vehicle mass distributionby subsystem


. . . and every material contributor

24%

Source: L. Cheah, PhD Thesis, MIT, September, 2010, p. 34.

Approximate material compositionof a typical automobile in the U.S.

Carbon

steel

44%

High-strength steel, 12%

Plastics and composites,8%

Other

21%

Iron, 8%

Aluminum, 7%

1945 First automobile developed with a

fiberglass composite body

1953 MFG launches the Corvette fiberglass body

1954 Thunderbird has a composite hardtop

1960 Sheet molding compound (SMC) invented

1968 Chrysler station wagon introduced with an

SMC rear air deflector

1970 Pontiac Tempest one-piece grille opening showcases

SMC’s ability to consolidate parts and reduce weight

Composites Composites –– and SMC and SMC –– have earned a place at the tablehave earned a place at the table

Brief history of composite applications in the US automobile industry


SMC’s ability to consolidate parts and reduce weight

1972 Corvette body panels are converted to SMC

1981 Composite leaf spring introduced on the Corvette

1987 Mercury tracer bumper beam becomes the first SMC structural part on an automobile in North

America

1996 Ford introduces SMC front-end system on Taurus and Sable

2003 “Tough Class-A” SMC improves surface quality on painted parts

2004 “Ultra Low Density” SMC is developed with hollow glass microspheres for a sunroof application

2007 Nano-Lite® SMC introduced as a 1.55 sp.gr. density SMC for vehicle body panels

Sources: Automotive Composites Alliance website; Plastics Technology, Oct. 2005

The advantages of composites are well knownThe advantages of composites are well known

• High strength (esp. stiffness) to weight ratio

• Ability to consolidate multiple components into a single molding


• Highly corrosion resistant

• Can handle intricate and complex geometry

Typical “standard density” SMC has three components*Typical “standard density” SMC has three components*

Glass 30%2.6

Resin 25%1.0 1.9

Component Composition

Density(g/cm3)


Resin 25%1.0

Filler 45%2.7

1.9g/cm3

Densities and composition represent a “generic” SMC for illustrative

purposes. In practice, density of individual components varies, and

SMC compositions can differ markedly from the generic mix shown.

*

Applying the density, mass, volume principle to SMCApplying the density, mass, volume principle to SMC

Glass 2.6

Resin 1.0

Filler 2.7

Density reminder

Reduce SMC part weight

M = D • V

Increase SMC strength to allow part design to accomplish objectives with less material volume

Alter the SMC components to reduce density without compromising mechanical properties

Idea/opportunity Consequence

� Lower the glass content � Immediate negative impact

on strength

� Lower the filler content � Reduces surface quality and

impact strength; increases

cost and worsens shrinkage

Idea/opportunity Consequence

� Replace glass fibers with

high-strength alternatives

(carbon, aramid or metal)

� Expensive and difficult to

process with current SMC

technology

� Introduce carbon

nanotubes or graphene

� Very expensive and difficult

to process with current

Strategy 2Strategy 1


cost and worsens shrinkage

(dimensional control)

� Substitute other fibers for

glass

- polypropylene

- nylon

- agricultural (hemp,

jute, pecan shells)

� Beneficial impact on

density, but these

alternatives are difficult to

process with existing SMC

technology and equipment

and can limit strength

� Supplement/replace filler

with functional additives

- hollow glass

microspheres

- nanoclays

• Microspheres effective on

density, but reduce

strength, cost more, and

traditionally have presented

serious practical challenges

to part surface quality;

nanoclays effective, at cost

increase

nanotubes or graphene

platelets to the filler

to process with current

SMC technology – but, may

become more viable in the

future

What is needed . . .

A low-density, high-surface quality SMC

with mechanical properties comparable to

standard density material, and which is


standard density material, and which is

economically viable for a wide variety of

automotive applications

A number of development constraints were selfA number of development constraints were self--imposedimposed

Development constraints on the low-density SMC program:

• Develop a tough material with improved stiffness to weight ratio

• Do not use hollow low-density fillers or spheres that can

potentially cause issues in customer finishing lines or high

water absorption in field applications


• Stay within strict parameters for:

- cost

- mechanical properties

- surface quality

• Abandon systems quickly when they do not show potential to meet the design objectives

Comparison of mechanical Comparison of mechanical properties of low density properties of low density SMCsSMCs

Test Property1.43 Sp Gr

Material

Conventional 1.9

Sp Gr Class A

SMC

Earlier

developed 1.55

Sp Gr Class A

SMC

Tensile Strength, Mpa 79 90 85

(Strength : Weight)Tensile Str:

Sp Gr Ratio55.2 47.4 54.8

Tensile Modulus, Gpa 8.8 12.2 9.2

Flex Strength, Mpa 161 195 180

Flex Modulus, Gpa 8.2 11.8 8.9

Impact - Izod, Notched, J/m 1158 945 750

Property values are typical of production Property values are typical of production

lots and are not guarantees of performance.lots and are not guarantees of performance.


Impact - Izod, Notched, J/m 1158 945 750

Impact- Reverse, in-lb 12 10 10

Water Absorption, % 0.38 0.41 0.8

Shrinkage, % 0.035 0.038 0.08

IMC Adhesion - Including 600

Hrs HumidityPass Pass Pass

Paint Adhesion, Hrs - per

customer SpecPass Pass Pass

Structtural Adhesive -

Customer spec - with Pliogrip

9100 system

Pass Pass Pass

Sp Gr 1.43 1.9 1.55

Glass % 29.8 29 34.5

Hardness 45 45 45

Poisson's ratio 0.303 0.31 Not conducted

CLTE, ppm/oC 26.81 18.51 23.6

ALSA Index 100 55 58

Creative � Reliable � CompositesSPE ACCE 2011 – Troy, MI – September 13, 201113

Benefits achieved by the new SMCBenefits achieved by the new SMC

• Delivers a 25% reduction in density overstandard SMC . . . and 8% reduction over

previous “best” available low-densityClass A SMC formulation

• Extremely tough . . . great for both

structural and appearance panel

applications


• Does not include microspheres, allowing part surface

quality to be maintained throughout finishing operations

and downstream processing

• Economically viable for a range of automotive applications

• Demonstrates a 25% reduction in molding pressure, reducing wear and

tear on molding machines, seals and hydraulic systems

Application targets and the future for 1.43 density SMCApplication targets and the future for 1.43 density SMC

• Battery covers and trays

for electric vehicles

• Underbody shields (stone

guards, fender wells, etc.)

• Body panels

• Structural systems (door

Near-term application targets for low density SMC


• Structural systems (door

frames, hood and trunk

reinforcements)

• Electric vehicle chassis

• Bumpers

• Oil pans, valve covers and

other engine components© Avi Abrams

Application targets and the future for 1.43 density SMCApplication targets and the future for 1.43 density SMC

• Further reduction of density below 1.43

• Continued improvement

of economics

Focus of future development work


• Improving surface

quality without

sacrificing density

or strength




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(614) 870-5000

www.coremt.com

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