16.05.2017 - Materialien des Karosseriebaus, Bad Nauheim

David Roquette, Dr. Florian Meyer - AUDI AG

Dr. Lars Herbeck - Voith Composites GmbH & Co. KG

High Volume Manufacturing of

Carbon Fiber Reinforced Plastics for Body in White

› Global and Automotive Trends

› Projects and Aims for the Introduction of CFRP

› Technology Development Carbon Rear Wall

› Realization at Voith Composites

› Conclusion

Content

Global Trends - Challenge for the Automotive Industry

Regulations

Emissions and Electrification

Individualisation

Sustainability

Digitalisation

Smart Connect

Automotive Trends - Challenge: Weight Increasing Factors

► Innovations and comfort- e.g. for self driving concepts

► Safety requirements

► CO2 emissions – e. g. electrification of power train (PHEV, BEV, …)

► Legislation (NOX, Ad Blue…)

► Country specific regulations

Density of steel, aluminum, carbon fiber reinforced plastics (CFRP)

approx. 5:2:1

Costs

approx. 2:10:50

Weight reduction potential in body applications

approx. 100:70:60

Efficient weight reduction (€/kg) as the aim for the Audi Multimaterial Space Frame.

The right material at the right place in the right amount

Typical Materials for Body in White

7,8

2,7 1,5

Density

[kg/dm³]

2

4

6

8

10

0 Steel CFRP Aluminium

Steel

Normalized

car-body

weight[%]

100

0 Steel Aluminium CFRP

Aluminium CFRP Steel

Cost

[€/kg]

0

Bugatti Veyron

First-time evidence Class-A

LB Gallardo Spyder

Class-A evidence with large, horizontal

component

R8 Coupé predecessor

Sideblade with visible-CFRP

R8 Spyder predecessorNumber of

units 20/day Class-A CFRP

RS3 Number of

units 40/day Class-A CFRP

R8 e-tron CFRP in structure

CFRP in crash area

New Audi R8 /

Lamborghini Huracán

Number of units 45/day CFRP in

structure Standardization

CFRP in structure Cost reduction

with high number of units

New A8 Number of units

150-300/day Industrialization

tech

no

log

ica

l le

ve

l

Class-A in RTM with large

component

Visible CFRP in RTM

Complex geometry

Number of units

Maximization of lightweight

potential

CFRP in structure Cost reduction

Class-A in RTM

timeline

Projects and Aims for the Introduction of CFRP

1st step: development of basic technology Class-A and visible-CFRP

2nd step: built up competence for high volume

3rd step: cost reduction and integral design

Breakthrough technologies are developed at the Audi Lightweight Center and

transferred with potential suppliers to serial production.

Material and Process Development for Large Structures with Integral Design

2012 2014 2015

R8 (MSS) Coupé

Differential Design

Predevelopment Project

R8 (MSS) Coupé Integral Design

2013

R8 (MSS) Spyder

Integral rearwall and B-pillar

R8 Prototypes

R8 (MSS) Spyder Integral Design

2016 2017

Approach and Realization: Integral Design and High Volume

3rd step: cost reduction and integral design

2nd step: built up competence for high volume

A8 (D5)

Integral Design High Volume

Carbon Rear Wall

A8 Prototypes (D5)

CFRP in the Audi R8 and the New Audi A8 - Multimaterial Audi Space Frame

Audi R8 Coupé and Spyder

Modular Sportscar System (MSS) New Audi A8

Small Series to

High Volume

› Single part reduction and integration of function due to an integral design

› Preassembled module within assembly line

› Highly anisotropic layup with localized load paths

1

2

Necessary Steps in Technology Development from R8 to A8

Appropiate composite-based design

Materials & Technology

› Cost efficient Composite Solution Package (Carbon Fiber, Resin & Adhesive)

› New Ultra-RTM Technology (low mould pressure/ robust process / short cycle-time )

› Innovative direct fiber placement technology (reduced scrap & optimized layup)

› Highly automated and linked manufacturing process

Carbon Rear Wall Structure - Functional Integration

Density

-45%

1

D4 – Current A8

D5 – New A8

Weight

-50%

D4 D5 D4 D5

Single part reduction and integration of functions are realized due to an integral design.

Preassembly of several components parallel to assembly line.

Carbon Rear Wall - Maximizing Anisotropy 1

Minimum use of carbon fiber due to highly anisotropic layup with localized load paths.

Highlights

› 6-19 optimized layers

› High variety in part thickness:

1.5 / 1.7 / 2.5 / 2.7 / 3.7 mm

› 30% of static torsional stiffness are

related to the carbon rear wall

Materials - Efficient Composite Solution Package 2

Carbon Fiber

Zoltek Panex PX35

• Zoltek PX35 50k large tow fiber

• Optimized balance of performance and

costs for high volume applications

• Long term price commitment

up to 7 years

• Textile Type PAN based precursor

• Stability of Supply

Resin & Internal Mould Release

VORAFORCETM 5300 - Epoxy RTM

• Curing time 90-120s @120°C

• Open - Cure time ratio 1:2

• Processing viscosity <20mPas

• Latent reaction behavior

• Effective mold release

• Excellent fiber adhesion

• No post cure required

• High machine compatibility

Adhesive

BETAFORCETM 9050M

• Used for metal inserts and assembly

• Compatible with VORAFORCETM & IMR

• Pretreatment-free adhesion

• heat accelerated cure and ambient

temperature latency

• Multi material mix – Da management

(high elongation and stiffness)

price-performance ratio for tensile properties

Composite stiffness GPa/€

Co

mp

osi

te s

tre

ng

th M

Pa

/€

performance

automotive fibre low-cost

automotive fibre

Source: Dow Automotive Systems Source: Dow Automotive Systems

Large Parts

Low Pressure

Fast Injection

Technology and Process - ultra-RTM D5 Prototype 2

Standard-HP-RTM:

„pick only two“

Main challenge: Infiltration of complex parts with ultra-fast-cure resins and very low cavity

pressure could be solved by innovative process controlled injection and press step.

Ultra-RTM

Fibre clamping resin stops at clamping, no resin sealing needed

Resin Shot weight: 1.3 kg

Sprue: point injection, no resin channel

Mass flow: 130 g/s

Time press

open to open: <180 s

RTM-tool bottom side RTM-tool with dry preform Cured part before demoulding Dry fibers outside clamping

ultra-RTM technology can produce the same quality with smaller, efficient hydraulic presses

and a very robust process also for high fiber volume content (50-55%).

Technology and Process - ultra-RTM D5 Prototype 2

0

5000

10000

15000

20000

25000

0 05 10 15 20 25 30 35

forc

e [

KN

]

time [s]

0,0

0,2

0,4

0,6

0,8

1,0

0 05 10 15 20 25 30 35

ga

p h

eig

ht

[mm

]

time [s]

0

20

40

60

80

100

120

140

0 05 10 15 20 25 30 35

pre

ssu

re [

ba

r]

time [s]

Injection Compression Curing

In Mould Pressure During Injection

Press Force During Process

Gap Height During Process

130 g/s

65 g/s

>130 g/s

En

d o

f in

ject

ion

En

d o

f co

mp

ress

ion

HP-RTM „classic“

Advanced RTM

ultra-RTM

2500t Press Force

350t Press Force

Technology Transfer to Serial Production

Breakthrough technologies are developed at the Audi Lightweight Center and

transferred with Voith Composite to serial production.

Voith Composites

From Fiber Straight to Component

… manual processing

Yesterday ... Today …

… automated processing

Elimination of expensive semi-finished products, reduction of cycle time due to elimination of

process steps, completely digitalized production based on “Carbon Production 4.0“

16

Voith Composites | Bad Nauheim Materialien des Karosseriebaus | 16. Mai 2017 | confidential 17

Industrialized Process Chain CFRP Rear Wall Audi A8

Materials Assembly Semi finished Preforming Consolidation Milling

Mostly industrialized Mostly industrialized Manufacture

Sta

nd

ard

Materials Preforming Consolidation

Industrialized Production

Assembly Milling

Le

an

Fiber Placement (VRA)

3D Forming 3D Cutting Ultra RTM Process

CNC Milling Surface Cleaning

Riveting & Bonding

Fiber & Binder Resin Metallic Attachment Parts

De

tails

Voith Composites | Bad Nauheim Materialien des Karosseriebaus | 16. Mai 2017 | confidential 18

Process Chain Step: Voith Roving Applicator (VRA)

Fiber Placement 3D Forming 3D Cutting Ultra RTM CNC Milling Cleaning Assembly

• Industrialized production line

• Near net shape fiber placement

• Automated quality control

• Fully digitalized

• Flexible 2D fiber layup

• Variable fiber angle

Voith Composites | Bad Nauheim Materialien des Karosseriebaus | 16. Mai 2017 | confidential 19

Fiber Placement 3D Forming 3D Cutting Ultra RTM CNC Milling Cleaning Assembly

Process Chain Step: 3D Forming

• Segmented stamp forming

• Complete automated handling

• Forming process 2D 3D

• Activation of binder

• Tailored Preforms

• Stabil in RTM process

Voith Composites | Bad Nauheim Materialien des Karosseriebaus | 16. Mai 2017 | confidential 20

Process Chain Step: Injection & Consolidation Ultra RTM

Fiber Placement 3D Forming 3D Cutting Ultra RTM CNC Milling Cleaning Assembly

• Fully industrialized process

• High production rate

• Curing time < 120 s.

• Low injection pressure

• Optimal surface quality

• No fiber washing

Voith Composites | Bad Nauheim Materialien des Karosseriebaus | 16. Mai 2017 | confidential 21

Process Chain Step: Riveting and Bonding of Metallic Parts

Fiber Placement 3D Forming 3D Cutting Ultra RTM CNC Milling Cleaning Assembly

• Surface cleaning with water

• No mechanical treatment for

bonding necessary

• Fully automated bonding

• Fast curing 2k PU System

• Automated riveting

• Riveting force documentation

› The new A8 CFRP Rear Wall has a weight reduction of 50% compared to the current A8.

› Breakthrough technologies have been developed at the Audi Lightweight Center and together with Voith Composites transferred to serial production.

› Due to the new developed technologies it is possible for the first time to use the full potential of CFRP within high volume.

› Lean production: Voith Roving Applicator for elimination of semi finished products

› Industrialization: mechanization and automation of processes

Conclusion

TechDay Body Structure

Thank you