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