Joining Lightweight Automotive Structures - · PDF fileJoining Lightweight Automotive Structures ... advanced materials – Joining of dissimilar materials ... Advanced Composites

Joining Lightweight Automotive Structures

Richard HewittTHURSDAY 24TH NOVEMBER 2011

+44(0) 24 765 75358

The Challenge

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Trends in Vehicle Weight

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Future Government Legislation

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Understanding global regulation / legislation will guide strategy for growth in new markets.

Weight Reduction OEM Status – EU.

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Market Drivers & Focus

Drivers

• Government Regulation– US – CAFÉ 35.5mpg by 2016– EU – 120kg/KM C02 by 2015– Dveloping Countries

• Improved Safety Standards

Area of Focus

• Product Design– All Steel BIW for A&B Segments– Steel and Aluminium BIW for B,C & D

Segments– All Aluminium D & E Segment –

luxury vehicles• Improved Safety Standards

– US – 5 Star rating (US NCAP)– EU – 5 Star rating (EU NCAP)– Developing Countries

• Consumer Pressures– Environmental awareness– Carbon Footprint– Demographic downsizing

luxury vehicles

• Manfacturing– Handling, Forming, cutting of

advanced materials– Joining of dissimilar materials– Corrosion concerns– Recycling

Market Drivers and Areas of Focus – Multi material design and manufacturing.

The Consensus Product Roadmap, mutually agreed by OEMs, defines future direction to develop

products that will benefit UK plc

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NAIGT Road Map

Common Research Agenda summary

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The Automotive Challenge

WMG © 2011 Slide Courtesy BMW

Improvement Opportunities within the product.

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Lightweight Materials

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Joining Techniques in Vehicle Manufacture

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Joining Polymers

Light Weighting Motivation

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Materials

• Metallic Materials–High Strength Steels–Aluminium Alloys–Magnesium Alloys

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–Magnesium Alloys–Titanium Alloys

• Non-metallic Materials–Polymeric Materials–Composites

Status:• Reviewed Studies created by

OEMs and Government agencies

Future Materials in BIW

2015 Forecast

Conclusions:• All Steel BIW

– Max 20% weight reduction possible

• Multi material (Cost Effective)– Max 40% weight reduction possible– Material: Mg. Al, Steel, Composites

• All Aluminium– Max 40% weight reduction possible– Materials: Cast, extrusion, stampings

Aluminium content in BIW and chassis expected to grow by up

to 30% by 2015

Joining Centre

Leigh Smith

• Resistance Spot Welding

• Self Pierce Riveting

• CMT / MAG / MIG

Richard Hewitt• Project Manager

• KTP Programme SFS Performance, Robot wrapping of Silicon Hose Manufacture

• DTI – Remote Fibre Laser Welding Programme

• Automation of Wind

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Further Staff:Research:

• Martin Thornton• Dezhi LiTechnician:

• Darren Grant

MIG

• Plasma

Dezhi Li

• CMT / MIG

Nic Blundell

• Granular Hot Melt

• Spot Friction Welding

• Remote Fibre Laser Welding Programme.

• Automation of Wind Turbine Manufacture.

• Adhesive process assurance systems

Background

Environmental concerns

Use light weight materials,e.g. aluminium, polymer composites, HSLA

Customer expectations

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Challenge traditional joining techniques

Improved fuel economy

£ + ?

Reduced emissions

Self-pierce riveting (SPR)

Remote Laser Welding(RLW)Spot Friction Joining (SFJ)

Single Sided

Resistances Spot Welding (RSW) MIG/MAG/CMT Welding

Distortion

• Core Partners Existing Partners:

Partners

The BIW Guild

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The BIW Guild

● And New (mainly exploiters)

•A&M Metals, ATL UK, Axis Engineering, Birmingham Specialities Ltd, Brookvale Manufacturing, Carrs Tool Steel, Oak Engineering, Frank Dudley Ltd, Webasto, etc.

Testing Facilities:•Metallurgy Laboratory

• SEM (Scanning Electron Microscope)• Optical Microscopes• Sample preparation and Mounting facilities• CT Scanner

•Testing Facilties:

Lab Facilities

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•Testing Facilties:• Instron Tensile Testing Machines• Instron Fatigue Testing Machines• High speed impact testing• Erichson Material Testing

Application Kit:•Fronius CMT Welding Set mounted on an ABB Robot•4kW IPG Fibre Laser Mounted on a Comau Smart Laser Robot.•ARO Weld gun with Bosch/Matuschek/ ARO Weld Controller on Comau Robot•Henrob/Böllhoff Self Pierce Rivet Pedestal Guns•Multiple marking Lasers•6kW CO2 Remote Welding and Cutting Laser

40

Aluminium Body Joining

A. Drivers– Reduced Initial Cost Investment– Reduced Piece Cost– Proving Process Capability

SP

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0

5

10

15

20

25

30

35

SPR RSW SFJ

$ (1

,000

,000

)

Robots Joining Equipment

Electricty Consumables

RSW

SFJ

SPR

Without Buffing (700 Welds)

With Buffing (10,000 Welds)

Implementation

• Resistance Spot Welding:– Evaluation of process feasibility for production line trial when applied to

specific assembly – X350 Dash Panel.– Installation of Production Trial Jaguar, Castle Bromwich August Shutdown– Installation of production cell for Wheel Box Assembly for Land Rover

Defender at Sertec

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Remote Laser Welding Pilot Cell

Laser

Technology

Application

Technology

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Materials

Technology

Application

Demands

Cell Commissioning at WMG March 2008Cell Commissioning at WMG March 2008

Interface width

Penetration

Porosity

WELD OK/NOKPower

Speed

Focus

Incident angle

Parameter

Gap - tooling

Gap - degassing

Stitch profiles

Flange condition

Joint condition

PROCESS WINDOW PROCESS STABILITY

Process Window & Stability Evaluation – DoE Principle

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Porosity

Weld strength

Surface Concavity

Top Bead Width

Top Surface Cut Through

Spatter

Burn Through

Envelope

Repeatability

Focus drift

On/off test

System Performance

Stack-up

Coating

Material type

Contamination

Material

PROCESS STABILITY PROCESS STABILITY

INDUSTRIALISATION

Component Trials

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RSW vs. RLW vs. SPR Joint Cost

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Energy Efficiency

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1mm to 1mm AA5754Comparison

Graphs show:• Comparability of Joint Strength & Joint Energy at 1mm to

1mm.• Allowing judgments to be made on stitch length and

shape required to replace existing joints.• Dependant upon specific failure mode• Results still required from fatigue tests

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RSW Joints:

3RT through to 6RT

SPR Joints:

3mm & 5mm Rivet

RFLW Joints:

10mm to 25mm stitch Length

Linear / Circle / Staple

System Comparison

AREA REQUIREMENTS

Conventional Process

890M2 x 2 = 1,780M2

Laser Process

511M2 x 2 = 1,022M2

Each Layout is X2 and includes:

• 1 for Front Doors

WMG © 2011This document is provided courtesy of COMAU group. It must not be communicated to third parties nor re produced without prior written authorisation of COM AU and its contents must not be disclosed.

Layout

OPERATORSAFETYAREA

OPERATORSAFETYAREA

OPERATORSAFETYAREA

OPERATORSAFETYAREA

OPERATORSAFETYAREA

GUN ACCESS AREA

OPERATORSAFETYAREA

GUN ACCESS AREA

OPERATORSAFETYAREA

GUN ACCESS AREA

OPERATORSAFETYAREA

GUN ACCESS AREA

OPERATORSAFETYAREA

OPERATORSAFETY

AREA

• 1 for Front Doors

• 1 for Rear Doors.

NO OF OPERATORS

Conventional Process 8 + 8 = 16

Laser Process 6 + 6 = 12

Facility Costs

Laser Process

=

Conventional Process + 1.9%

(After initial evaluation only)

General Guidelines

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Design Optimisation

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Industrial Installation

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UHSS (boron steel)

Significant opportunities in using UHSS�Light-weighting via down-gauging

�Improved crash performance

HOWEVER : Challenges to formingHOWEVER : Challenges to forming� Limited RT formability (low elongation, high forces)� High spring-back

Hot forming – die quenching� Eliminates spring-back � High ductility� Fully hardened (cooling rate

dependent)

Hot-forming route

‘Direct process’1 – Austenitisation of blank @ 850-950°C2 – Rapid transfer3 – Forming-cooling operation

As-received Ferrite-Pearlite

Austenitization in furnace

Forming & quenching

Fully hardened part

Typical applications

Ford Fiesta (2011)A-pillar

Typically A/B-pillar, roof, side rails….

Volvo C70ROPS – reinforced A-pillar

Challenges: tailored microstructure

Best crash performance achieved with different properties

- B-pillarCan be achieved by:� tailor welded blanks� Differential tool cooling

- Tailored microstructure - Tailored microstructure

Fully hardened microstructure

Controlled cooling

Concept Vehicles

Concept Vehicles

ThyssenKrupp Steel EuropeInCar Project

Concept Vehicles

EDAG –Light Car

Manufacturing Concept

Research contextMain challenge: multi-material concepts

Steel Spaceframe Advanced

Affo

rdab

ility

of w

eigh

t red

uctio

n Design

Materials Processes

AdvancedLM-Spaceframe

MultiMultiMaterialMaterialConceptConcept

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AdvancedComposites(FRP)

Spaceframe

Composites

Advanced Steel body

Coil-coatedshell

Steel thin wall casting

High strength Steels

Al-Spaceframe

SteelSteelUnibodyUnibody

Stainless Steel Spaceframe

Affo

rdab

ility

of w

eigh

t red

uctio

n

Approach> 2012

SLC Approach –Final Step

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The Future

The Challenges

• Robust application and joining of innovative new materials

• High Strength Steels

• Light Weight Materials

• Composite Structures

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• Composite Structures

• Advanced simulation techniques

• Meeting the requirements of advanced structures – Single Sided Joining.

• Improved complexity management

• Enhanced Design for Manufacture / Assembly

• Integrated development with UK Supply Base

• Material Characterisation

• Flexible Tooling for increased utilisation at Low Volumes.

Summary

• There are a wide range of engineering materials available for automotive weight saving applications

• There is a corresponding range of joining

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• There is a corresponding range of joining processes available for these materials, each with their own technical and economic merits

• The capabilities and limitations of these joining processes need to be understood to maximise both assembly and joint performance.

Contact Details

Richard Hewitt

Project ManagerPremium Vehicle Light Weight Technologies CentreInternational Automotive Research CentreWMGUniversity of Warwick

WMG © 201115 December 2011 WMG 45

University of WarwickCoventry CV4 7AL

Tel +44 (0)24 765 75358Email [email protected]

www.wmg.warwick.ac.uk

Joining - Http://www2.warwick.ac.uk/fac/sci/wmg/research/pard/pardprojects/advbodyjoinLow Carbon – http://www2.warwick.ac.uk/fac/sci/wmg/research/low_carbon/wmg_lowcarbonbro_09.pdf

• Thank you for your attention

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• Any Questions