Technology management in automotive industry

Department of Mechanical Engineering
Automotive Technology Management, 2007
Rishabh Dudheria -I-
ABSTRACT
Innovation is the key to obtain competitive success. One of the challenges for the
automotive industry is to come out with new products technologies on a regular basis.
Also technology management is the heart for the creation of new products and
systems and it involves developing and operating technology strategy, organization,
processes, and resources. Identifying the key technologies and addressing their
challenges would be one of the important aspects of the technology management.
The concern about strict environmental regulations and depletion of fuel resources is
increasing importance for the development of green technologies in cars. One of the
promising technologies is by reducing the weight of vehicles and thus lowering the
rate of fuel consumption and emissions.
In this report the generic technology management methods and innovation models is
reviewed, a comprehensive study of lightweight joining processes such as: resistance
spot welding, laser welding, metal inert gas welding, self piercing riveting, adhesive
bonding and friction stir welding is done. The joining process will be compared and
the basis for selection of a process will be discussed.
A technology management model is developed which would help a technology
manager to manage and explore the growing technologies. This management model is
studied and discussed by applying the lightweight joining technology.

Rishabh Dudheria -II-
CONTENTS
LIST OF FIGURES………………………………………………….…………1
LIST OF TABLES………………………………………………….…………..2
ABBREVATIONS………………………………………………….…………..2
1.0 INTRODUCTION………………………………………………………3
1.1 Background………………………………………………………3
1.2 Aims and Objectives……………………………………………..4
2.0 TECHNOLOGY MANAGEMENT…………………………………….5
2.1 Introduction ……………………………………………………...5
2.2 Global market trends…………………………………………….5
2.3 Technology drivers………………………………………………7
2.4 Technology life cycle……………………………………………8
2.5 Technology management technique……………………………10
2.6 Technology management challenges…………………….……..14
2.7 Understanding innovation ………………………………….…..15
2.8 Management models……………………………………………17
2.9 Summary………………………………………………………..20
3.0 LIGHTWEIGHT STRUCTURES…………………………………..…21
3.1 Introduction……………………………………………21
3.2 Aluminium……………………………………...……..25
3.3 Lightweight joining techniques ………………………29
3.4 Resistance spot welding…………………...…………..30
3.5 Laser welding……………………………...…………..31
3.6 Metal inert gas welding………………..……………...37

Rishabh Dudheria -III-
3.7 Self – pierce riveting …………………..…………….38
3.8 Adhesive bonding……………….……….……………41
3.9 Friction stir welding………………..…….……………43
3.10 Summary……………………………..….…………….46
4.0 PROPOSED OUTLINE MODEL...…………………………………...54
4.1 Innovation model……………………………………………….54
CONCLUSIONS…………………………………………………..……….…62
ACKNOWLEDGEMENTS………………………………………….……….63
REFERENCES………………………………………………………………..64

Rishabh Dudheria -1-
LIST OF FIGURES
Figure 2.1 S- Shaped Curve shows the technological life cycle………………….......9
Figure 2.2 Technology Substitution…………………………………………………10
Figure 2.3 Business Model…………………………………………………………..11
Figure 2.4 Product Development Funnel……………………………………………12
Figure 2.5 Product Development Funnel……………………………………………13
Figure 2.6 Generic Innovation Processes……………………………………………14
Figure 2.7 Linear model of innovation………………………………………………16
Figure 2.8 Interactive model of innovation………………………………………….16
Figure 2.9 Ansoff’s product/ market grid…………………………………………..17
Figure 2.10 SWOT analysis strategies ……………………………………………...19
Figure 3.1 Carbon dioxide emissions sources……………………………………….22
Figure 3.2 Carbon dioxide savings per 100kg weight reduction…………………….23
Figure 3.3 SWOT analysis of Aluminium in BIW…………………………………..26
Figure 3.4 Principle of spot welding process………………………………………..30
Figure 3.5 Schematic Laser welding process………………………………………..32
Figure 3.6 Laser welding Cell……………………………………………………….33
Figure 3.7 Example of Laser welding process at TMC……………………………...34
Figure 3.8 MIG welding process…………………………………………………….37
Figure 3.9 Self pierce riveting process………………………………………………39
Figure 3.10 Dynamic and fatigue properties of various joining procedures………...41
Figure 3.11 Friction stir welding principle…………………………………………..44
Figure 3.12 Friction stir spot welding process………………………………………46
Figure 4.1 Innovation Management Model……………………….…………...……55
Figure 4.2 Process Selection Criteria………………………………………………..58
Figure 4.3 Process Comparison: Stiffness and Safety……………………………….59
Figure 4.4 Process Comparison: Cost Flexibility, Automation and Speed………….60

LIST OF TABLES
Table 3.1 Friction Stir Welding……………………………………………………...45
Table 3.2 Summary of joining process………………………………………………47
Table 3.3 Comparison of the joining techniques based on performance and safety...48
Table 3.4 Comparison of the joining techniques based on automation and cost……50
Table 3.5 Comparison of the joining techniques based on requirement and process
time…………………………………………………………………………………...52
ABBREVATIONS
RSW Resistance Spot Welding
FSW Friction Stir Welding
SPR Self Piercing Riveting
FSSW Friction Stir Spot Welding
MIG Metal Inert Gas

INTRODUCTION
1.1 BACKGROUND
In today’s highly competitive economy, it is important for a company to look out for
new technologies and innovation signals in order to be successful and competitive. To
come out with new products technologies on a regular basis is one of the technological
management challenges for the automotive industry.
Technology development is the heart of creation of new products and systems
technology management involves developing and operating technology strategy,
organization, processes, and resources. It touches almost every corner of business and
has a direct impact on the bottom line and on the shareholder value. Identifying the
key technologies and addressing their challenges would be one of the important
aspects of the technology management.
The rising concern about global warming and strict environmental regulations is
increasing importance for development of green technologies in cars , it is not only
exhaust gases that pose a problem, but also the waste produced during the
manufacturing process and disposal of vehicle at end of its useful life.
Weight reduction technology can be one of the solutions as reducing weight increases
fuel efficiency and thus lowers emissions and by using the appropriate lightweight
structure higher percentage of product can be recycled.
There are many weight reduction strategies such as:
 Selecting lighter or lower density materials
 Optimizing or improving existing designs
 Combining or eliminating parts, assemblies, and/or their function
 Removing content or features from the vehicle
 Revising manufacturing or assembly operations

In this project two weight reduction strategies are analysed and discussed. First one is
use of lightweight structures where aluminium’s potential to replace steel in
automotive bodies is analysed. Second strategy of lightweight joining is examined and
finally a developed of technology management model is studied for the production of
light-weight automobile body.
1.2 AIMS and OBJECTIVES
Based on the research requirements and review of the literature following project aims
and objectives were established.
1.2.1 AIM
To study how best practise of technology management technique might be
adapted for lightweight production of aluminium parts.
1.2.2 OBJECTIVES
1. Understand the generic technology management techniques.
2. To evaluate lightweight development of aluminium parts in production.
3. To identify technological challenges in the production of aluminium parts.
4. To examine which technology management technique can be adapted for the
lightweight production of aluminium parts.
The first section deals with the technology management where the global automotive
trends, major technology drivers in the automotive industry and life cycle of a technology are
explained. Technology management principles, innovation and management are studied.
In the second section aluminium’s potential to replace steel in automotive bodies is
analysed and a comprehensive study of lightweight joining processes such as:
resistance spot welding, laser welding, metal inert gas welding, self piercing riveting,
adhesive bonding and friction stir welding is done.
Finally the innovation management model for development of new products is
developed and explained using the technology of lightweight joining. The joining
process comparisons and selection criteria are also discussed.

TECHNOLOGY MANAGEMENT
2.1 INTRODUCTION
In today’s highly competitive economy, one of the major challenges for the industry is
to look out for innovative technologies which will facilitate increased
competitiveness. Innovation is no longer just a technological development, but more
important as it affects firm’s costs, competitive advantage, industry infrastructure, and
long term business results [1]
.
The basis for competition includes not only cost, but increasingly the technological
advantages which can be brought to their products.
Technology development is the heart of creation of new products and systems and
thus it is very important in the automotive industry to manage technological
development in order to come out with innovative products on a regular basis [2]
.
Technology management touches almost every corner of business as it involves
developing and operating technology strategy, organisation, processes and resources.
Identifying the key technologies and addressing their challenges would be one of the
important aspects of the technology management also it will be necessary to manage
these key technologies in order gain competitive advantage.
However, before discussing and understanding about technology management
techniques, it is necessary to recognize the global market trends in the automotive
industry and their implications on product development.
2.2 GLOBAL MARKET TRENDS
It is very important to understand the trends affecting the automotive industry as they
influence the development of new product and systems. In this section we try to

familiarize with the key trends which influence vehicle designs and functionality.
Some of the trends in the automotive industry are as follows [2]
:-
1. Sociodemographic trends:-
Sociodemographic trends include the characteristics
which necessitate the following:-
 Longer life of products
 More safety features, required mainly by older drivers.
 Increased comfort with demand for multimedia and computers as
people spend more time within vehicles.
2. Legislative trends:-
These trends are as a result of increase in regulations on
global basis, including mandates covering fuel economy, environmental
factors, and safety.
3. Industry trends:-
Industrial trends play in important role in influencing the
vehicle design process. The important observations of the industry trends are
the following:-
 Services are becoming the key differentiator.
 Global competition is driving exceptional productivity improvements.
 Automotive industry is driving shorter driving life cycles and
consequently, reductions in lead time.
4. Consumer preference trends:-
Consumer preference has always been influential in
product designs and requisite has been better price, quality, performance
service and maintenance, safety, comfort and convenience, fuel economy,
environment.
However the priority often depends on region like in Europe the fuel economy and
environment are the key trends, whereas in North America it is comfort and

convenience which are more important while cost and reliability are concerns in Asian
market. But these preferences are bound to change with rising concerns over global
warming, fuel depletion and environment [2]
.
Analysis of the trends helps us understand what is likely to happen in the automotive
industry. The above discussed market trends create several drivers for the automotive
product development.
2.3 TECHNOLOGY DRIVERS
Technological change occurs as a result of economic or social necessity. It is mainly
driven by a combination of external forces and is a product of creative attempts to
solve a problem [4]
.
Economics and human goals are the drivers of technological innovation. James Burke
designates six major initiators of technological innovation: Deliberate Innovation,
Accidents, Spin-offs, War, Religion and Environment [1]
.
The technological trends discussed in the section 2.1 create an opportunity for the
product development in many areas such as:
1. Safety: - It would be concerned with ultimate occupant safety which could
result in the development of occupant protection systems or collision
avoidance technologies.
2. Comfort and Convenience: - As people spend more time within their vehicles
it is not safety alone which is important but also developments in the field of
multimedia and electronic accessories which provide them with an enjoyable
driving experience.
3. Fuel Economy:- Increased concern about global warming is forcing the
automotive industry to look into development of alternatives to improve fuel

economy, there is continuous development needed in some of the important
areas such as:
 Internal Combustion
 Next Generation Propulsion Systems
i. Hybrid Vehicles
ii. Fuel Cell Systems
 Lightweight Materials
4. Environment: - One of the technological drivers is the environment which
sometimes dictates what must be done. It is not only important to address the
emissions from the vehicle but also necessary to concentrate on all stages of
the product life cycle, from design of parts and modules through design for
environment, design for recycling, and life cycle analysis followed by
procurement of materials and parts with a focus on using recyclates and
meeting environmental requirements[2]
.
Obviously, the trends affecting the automotive industry will influence what products
and systems must be developed and technology development is the centre of creation
of new products. Therefore it is necessary to know the management of technology in
order to come out with innovative products on a regular basis. Before management of
technology it is important to know the technology life cycle.
2.4 TECHNOLOGY LIFE CYCLE
Technical progress does not occur in random fashion. There are identifiable patterns
which provide strong clues to the future performance levels of a technology and their
timing. They cannot provide accurate forecasts but, they can give a picture of the
development process [67]
.
The S – shaped technology life cycle as shown in figure 2.1 represents the typical path
of a technological progress.

Figure 2.1 S- Shaped Curve shows the technological life cycle [1]
The S- curve in figure 2.1 shows the life cycle of a product or process. The figure
indicates that in early stages of the development, substantial funds are invested in
a new technology, and progress is minimal.
The centre of the curve exhibits the main period of exploitation of the technology,
it is a period of substantial pay back for little additional effort and investment with
the development of the knowledge and processes used to enhance the technology
[1]
.
Finally, it is observed that the technology approaches maturity, more money and
effort is invested for smaller returns. At this point the technology reaches its limit
or is on the verge of obsolescence, and new technologies compete with it for
dominance and increased performance and returns as shown in figure 2.2.

Figure 2.2 Technology Substitution [1]
The figure 2.2 shows that there is a new technology initiating at the limit of previous
technology trying to substitute the previous technology. It can be also noted that new
technology follows through a similar product or process life cycle as the previous
technology. This series of birth, development, maturity and decline repeats with each
technological advance in a seemingly permanent upward spiral of progress.
The key to successful exploitation of technology is managing the inevitable
discontinuities which occur when the mature phase of one curve is overshadowed by
the innovation phase of a newer, higher performing technology as shown in figure 2.2.
2.5 TECHNOLOGY MANAGEMENT TECHNIQUE
Technology can be managed in context with a business model which incorporates
business strategy, a customer focussed process, a supplier process and an internal
business process as shown in figure 2.3

Figure 2.3 Business Model [2]
The business model shown in figure 2.3 involves sales, marketing, purchasing,
engineering, and other functional areas [2]
.
The first column,” Explore Market and Plan Future,” is where the organization
understands the market opportunities, global needs of its customers, technological
gaps and its capacity and capabilities. The first step is followed by selecting and
developing the technologies. This involves Technology development process where
alternatives for products and processes are explored and developed, and advanced
development process through which developed technologies are incorporated into the
product and processes.
Manage program deals with processes by which organizations plan and harmonize
programs. This is commonly called the product development process which focuses
on the design and delivery of a validated product in quantity prior to production.
Finally the manufacture product deals with the manufacturing facilities and includes
the product production processes and continuous improvement efforts.
In the above model it is the development of the technology which is of prime
importance. The generic representation of product development process could be

thought as a “funnel” which takes in ideas and opportunities from multiple sources at
the top end and converts them into value through multiple vehicles, as shown below in
figure 2.4 [39]
.
The figure2.4 shows the several other stages in the funnel which help in obtaining
value products.” Ideation and Screening” is a systematic way of converting raw ideas
into something that can be used to create new products and services. The ideas could
also come from suppliers if a process exists for listening to them.
Figure 2.4 Product Development Funnel [39]
The Product Development Process comprises of sub-processes dealing with managing
projects and programs that convert ideas into new products or improve the existing
products. The process of Commercialization and Rollout ensures that maximum value
is wrung out of the innovations thus developed.
The funnel is supported by two supporting processes, one dealing with information
and intelligence further supported by knowledge management system and the other
with product and technology planning.

The technology development and exploitation can also be represented by a funnel
similar to the product development funnel [2]
. These two funnels interact strongly with
each other, the needs of product determining what technology will be developed and
the technology development dictating what products can be offered to the market
place. The complete framework for managing technology is as shown in figure 2.5.
Figure 2.5 Product Development Funnel [2]
Intelligence is the knowledge from the outside world: the technologies that are being
developed, market’s demand. The “vision” drives both the funnels with a clear idea of
the organisation and shows how technology and product development can help
achieve it. Finally “value” is the result of a successful technology or product
development effort.
Technology Development is a critical element in the development of new products
and systems and the transformation of the automotive industry poses several
challenges to the way technology is managed.

2.6 TECHNOLOGY MANAGEMENT CHALLENGES
There are many challenges faced by that automotive industry which can be solved by
effective management of technology. Some of the major ones are listed below [2]
:-
1. Developing new products is one of the major concerns in the automotive
industry.
2. The capability to do more work with fewer resources and do the process at
good speed.
3. To use external sources – suppliers, customers, universities, government and
so on to gather new ideas.
4. To squeeze additional value out of technology.
Innovation is the key for development of new products and thus it is important to
know the innovation process and understand the different models of innovation.
2.7 UNDERSTANDING INNOVATION
Innovation is no longer just a technological development, but more important as it
affects firm’s costs, competitive advantage, industry infrastructure, and long term
business results [1]
.
The generic innovation process comprises of idea creation, invention development,
innovation launch and finally generating impulses as shown in the figure 2.6 [6]
.
Figure 2.6 Generic Innovation Processes [6]

1. Create an idea: The first stage is the creation of an idea which is triggered by
one or more impulses, and is a creative spark or awareness of a problem or a
new perspective on a topic.
2. Develop an invention: The idea creation is followed by developing an
invention where the general objective is to create a tangible manifestation of
the idea and at this point there is no certainty of commercial application.
3. Launch an Innovation: After relating to market studies and aligning potential
product strategies with the company strategy, a systemized production concept
will be worked out involving suppliers and sales channels. In the end, the
customer’s acceptance will decide, whether or not it is a viable product
innovation.
4. Generate Impulses: The experience built during the innovation process grows
the intellectual property of the organization and its partners. Specifically, the
involved individuals learn and enrich their basis for deriving creative sparks,
identifying problems, determining new perspectives, and therewith create
impulses for new ideas.
Basically, innovation depends on invention but inventions are to be controlled before
it uses its power. Therefore, innovation is the management process of new idea
generation, technological improvement, manufacturing and marketing. There have
been various innovation models developed in order to study the innovation process
such as linear model, simultaneous model, and interactive model [4]
.
1. Linear Model: - This model is the simplest model of innovation, it has two basic
types: the technology push and market pull model as shown in the figure 2.7.
First type is technology driven model, known as technology push, where technological
improvements and new discoveries will create new products. Finally, marketing and
sales will promote products to consumers.

Figure 2.7 Linear model of innovation
In the second type called the market pull model, the marketplace or consumers have
an influential role in the process. Here products are determined by demand and
interests of consumers as represented in figure 2.7.
2. Interactive Model: - This model suggests that innovation occurs as a result of the
interaction between marketplace and technology. From figure2.8 it is clear that
research and development, manufacturing and marketing is the centre of the model
which looks same as in the case of linear model discussed above.
Figure 2.8 Interactive model of innovation
However, the relation may not be linear as there is a provision for feedback. Linkages
between science and marketplace occur in all communication flow as shown in figure
2.8. Finally, new idea is depended upon organisation capabilities, the needs of the
market place and science base [4]
.
Idea R&D Manufacturin
g
Marketing
Commercia
l product
Latest sciences and
technology
Advance in society
Needs in society
and the marketplace
Market
Pull
Technology
Push
Interactive model of innovation

In the next section some of the key management models or tools are examined for
their utilization in effective management.
2.8 MANAGEMENT MODELS
There are many management techniques and on evaluating them some of the
important models which would assist in successful management are as the following:
1. Ansoff’s product/ market grid:-
Ansoff’s (1987) product/market expansion
grid is a framework for identifying corporate growth opportunities. The two
dimensions: products and markets determine the scope of options as exhibited
from the figure 2.9.
2. Market Development Conglomerate
Diversification
4. Diversification
Vertical integration
Horizontal integration
1. Market Penetration 3. Product Development
Figure 2.9 Ansoff’s product/ market grid
There are four generic growth strategies which follow from the matrix as shown in the
figure 2.9 [5]
:
i. Market penetration: This denotes a growth direction through the increase
of market share for the current product-market combination.
Concentric
diversification
NewCurrent
Current
New
Products
Market

ii. Market development: This refers to the detection of new markets, channels
for current products.
iii. Product development: This deals with development of new products to
replace or complement current products.
iv. Diversification: This is important when both the product and market is new
to the corporation. It can be further divided into various specific growth
vectors as displayed in the figure:
 Horizontal diversification - when new technologically unrelated
products are introduced to current markets;
 Vertical integration - when an organization decides to move into its
supplier's or customer's business to secure supply or firm up the use of
its products in end products;
 Concentric diversification - when new products closely related to current
products are introduced into (new) markets;
 Conglomerate diversification - when completely new, technologically
unrelated products are introduced into new markets.
The grid serves as a means to describe product-market opportunities and strategic
options, and thus forms an excellent framework for exploration, description and
strategic dialogue.
2. SWOT analysis:-
SWOT analysis is establishing a current position of an
organization in the light of its strengths, weaknesses, opportunities and threats [5]
.
The first step in carrying out a SWOT analysis is to identify strengths,
weaknesses, opportunities and threats. Strengths and weaknesses are intrinsic
value creating skills or assets, relative to competitive forces. Opportunities and
threats however, are external factors. They are not created by the company, but emerge
as a result of the competitive dynamics caused by 'gaps' or 'crunches' in the market.
 Strengths: These are the things that the company is really good at. They
cannot be growing market values or newer products.

 Weakness: It is often seen as the logical inverse of the company’s threats
however these could not necessarily be a relative weakness.
 Opportunities: These are any technological developments or demographic
changes taking place, or could demand for your product or service increase as a
result of successful partnerships.
 Threats: The opportunity to a competitor could be a threat. Also changes in
regulations, substitute technologies and other forces in the competitive field may
pose serious threats to the company and could lead to lower sales, higher cost of
operations, higher cost of capital, inability to make break-even, shrinking margins
or profitability, rates of return dropping significantly below market
expectations.
The second step of the SWOT analysis is more challenging as the decision needs to be
taken based on the analysis. Figure 2.10 indicates the different strategies.
Strengths (S) Weakness (W)
Opportunities
(0)
SO Strategies:
Use strengths to take
advantage of
opportunities
WO Strategies:
Take advantage of
opportunities by
overcoming the
weakness or making
them relevant
Threats
(T)
ST Strategies:
Use strengths to avoid
threats
SO Strategies:
Minimise weaknesses
and avoid threats
Figure 2.10 SWOT analysis strategies [5]
 'SO' and 'WT' strategies : A company should do what it is good at when the
opportunity arises and steer clear of businesses for which it does not have the
competencies.
 'ST' strategies: There is lot of risk involved as companies adopting this strategy
essentially 'buy or bust' their way out of trouble.

 'WO' strategies: When a company decides to take on an opportunity despite
not possessing the requisite strengths, it must develop, buy or borrow the
required strengths.
It is clear that proper utilization of the above discussed management models will not
only help the organization with effective management but also alert them with some
of the upcoming challenges.
2.9 SUMMARY
The global automotive trends: sociodemographic, legislative, industrial and customer trends
were discussed as they influence the product development areas in the automotive industry.
The major technology drivers such as fuel economy, environment, safety and comfort were
listed and life cycle of a technology which is represented as an S - curve was understood.
Technology management principles were studied, management of technology in terms of a
business model was discussed along with the product development and technology
development funnel.
The important technology management challenges faced by the automotive industry and
were listed. A study of the linear model and interactive model of innovation and a
comprehensive analysis of some of the key management models: Ansoffs product/market
grid and SWOT analysis was done.

LIGHTWEIGHT STRUCTURES
3.1 INTRODUCTION
The rising concern about global warming and strict environmental regulations is
increasing importance for the development of green technologies in cars. It is not only
exhaust gases that pose a problem, but also the waste produced during the
manufacturing process and disposal of vehicle at end of its useful life. One of the
technologies to solve this problem is by reducing the weight [47]
of vehicles and
thereby lowering the rate of fuel consumption and emissions.
Also high recycling rates can be achieved by choosing the right material.
Research and development of ecological technologies in cars is becoming increasingly
important in the automotive industry. It is seen that one of the greatest trends of this
century to conserve natural resources and minimise air pollution, even the customer
choices and preferences are bound to change with rising concerns over global
warming, fuel depletion and environment.
As discussed in section 2.3 the key technology drivers in the automotive industry are
1. Environment: It has been found that road transport contributes 20% of the CO2 to
the atmosphere [48]
. It is therefore clear that automotive industry has to act and
come out with products which will minimize their effect on global warming. Also
it has been noticed that passenger cars contribute 58% of CO2 from road transport
as shown in the graph below and thus it is very necessary to focus on the
passenger car technologies.

Figure 3.1 Carbon dioxide emissions sources [48]
2. It is not only necessary to focus on the technologies which will reduce emissions
but also to necessary to concentrate on all stages of product life cycle. With
various legislations on end of life recycling and increased landfill costs it is
become imperative to look into technologies which address this problem.
3. Fuel Economy: As a result of depletion in the fuel sources and means to reduce
emissions, fuel efficiency has become one of the important drivers in the
automotive industry for the development of new products.
Clearly these drivers necessitate the development of new products and enhance the
technologies which support them. Therefore it is understood that one of the
technologies meets the above challenges is to reduce the weight of the body.
Vehicle weight reduction is essential for the future and is important method for the
fuel and emission savings as depicted from the graph representing the lifetime Carbon
dioxide savings per 100 kg weight reduction for road vehicles.
It is seen that 2.1 tonnes of carbon dioxide can be saved in a life time of a passenger
car with 100kg reduction.
0
5
10
15
20
25
30
35
40
45
50
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
MilliontonnesCarbon(MtC)
Other
International aviation
Civil aviation
National navigation
Public transport
HGVs
Light duty vehicles
Passenger cars

Figure 3.2 Carbon dioxide savings per 100kg weight reduction [63]
A rule of thumb is that 10% weight reduction approximately equals a 5.5%
improvement in fuel economy [56].
The body of a car, including the interior, accounts for nearly 40% of the car’s total
weight and offers a high potential for lightweight construction. If the body mass is
reduced, in theory, a secondary mass reduction can be realized. For example, the
chassis, brakes and gears can be designed to be smaller and lighter, resulting in a
reduction in the weight of the car [50]
. With this ripple effect, it is estimated that 10%
of vehicle weight reduction results in 8–10% of fuel economy improvement [56]
.
Weight reduction strategies:
1. Replacing the materials of high specific weight with lower density materials:
The general classification which would play an important role in selection of a
material for automotive body is:
 Design or Lightweight Performance: This would include crash and stress
analysis, and analyzing other mechanical properties such as impact resistance,
corrosion resistance, density and formability.
 Manufacturing: It is very important during selection of the material to analyse
its manufacturing process and its suitability to be used in high volume
production.

 Recycling: It is not only important in terms of environment but even
legislations are playing a key role to ensure the recycling of the vehicle after
the end of its life.
 Cost: This is one of the main criteria for any material to be used for mass
production. The various factors of cost which may be taken into account in
order to explore the ability of a material could be material cost, treatment or
manufacturing cost, tooling cost, and dismantling and recycling cost.
Dr. Wolfgang Ruch, the Director of the Aluminium Centre, Audi motors adds:
"Whenever we consider using other materials for our models, we have to take their
availability, cost, use in high volume and not least their suitability for recycling into
account” [65]
.
Though steel has been the most commonly used material [54]
for high production
vehicles, there have been many lightweight materials which have shown their
potential to be used in automotive vehicles.
Some of the materials are:
1. Aluminum
2. Magnesium
3. Plastics – Glass reinforced and Carbon reinforced
2. Optimisation of the production process:
Another way of realizing lightweight constructions is to optimize the production
process. The reduction of spot welds should reduce the body weight when replaced
by new joining techniques such as laser welding or manufacturing processes such as
hydro forming [50]
.
The two techniques identified for lightweight constructions will be considered by
studying aluminum as future lightweight material to replace steel in the body
structures and by evaluating various lightweight joining techniques.
First aluminium is explored with respect to is suitability as a lightweight material in
car body structures.

3.2 ALUMINIUM
Aluminum offers a lower weight alternative to steel, potentially increasing the
efficiency of vehicles and it also combines several other technical and environmental
advantages. However, the application of aluminum has been only in selected areas of
use such as cast aluminum in the engine, transmission, and wheels. Other areas offer
the potential for growth that could significantly expand the amount of aluminum used
in vehicles [25]
.
The body-in-white (BIW) offers the greatest scope for weight reduction with using
large amount of aluminum. Recent developments have shown that up to 50% weight
saving for the BIW can be achieved by the substitution of steel by aluminium. This
can result in a 20–30% total vehicle weight reduction when added to other reduction
opportunities [56, 25]
.
There have been two design approaches used for aluminum intensive vehicles: Space
frame design - which offers lower tooling costs by eliminating some stampings, and
the conventional sheet monocoque approach which has established processes and low
piece costs.
Following are examples of aluminum intensive vehicles which use aluminum in body
components:
Audi A2 use aluminum space frame construction that is welded, and riveted for
structural strength. The A2 aluminum body is 43% lighter than a comparable steel
body and Audi claims the resulting lightweight body is stronger than steel and
cheaper to repair. Its latest model Audi A2 1.2 TDI weighs only 855 kilograms,
has a fuel efficiency of 2.99 litres for every 100 km [64].
Audi A8 is an aluminum intensive space frame vehicle that reduces the body
weight by 40%. The 385 kg aluminum components comprise 125 kg sheet
products, 70 kg extrusions, 150 kg castings, and 40 kg other aluminum forms.

Honda NSX has also a stamped body structure and exterior panels with a weight
of 210 kg of aluminum, about 100 kg of aluminum chassis components and 130 kg
of other power train and drive train components.
Ford AIV has a stamped aluminum body structure. The body and exterior panels
are 200 kg lighter than the conventional steel model with 145 kg in body structure
and 53 kg in closure panels. The total usage of aluminum is 270 kg and the total
weight reduction is 320 kg [56]
.
A SWOT analysis of aluminum is presented as shown in figure 3.3, drawn by
identifying strengths and weaknesses of aluminum as a material and also recognizing
its opportunities and threats in the automotive body structures.
Figure 3.3 SWOT analysis of Aluminium in BIW [53]

One of the major strengths of aluminum is its weight; aluminum is proven to be 50%
lighter than conventional steel providing weight reduction by replacing steel in the
automotive body. Aluminium has the ability to absorb energy in a much higher level
than steel, thus providing good safety. Its high corrosion resistance, even in exposed
or inaccessible spots and excellent resistance to buckling [45]
makes it highly suitable
for the automotive industry. Also after its the end of life aluminum has the quality by
which it can be recycled three times without losing its properties[52]
and using only a
fraction of the original energy consumption for its recycling, much less than that
required for recycling steel.
One of the main advantages or using aluminum is that the aluminum parts can be
highly sophisticated in their design due to the formability thus reducing the number of
parts by up to 50% needed for construction, as one part can replace a complex part
consisting of several steel panels.
As discussed in section 3.1 the rising environmental concerns and legislations
supporting the recycling of material and reduction in emissions create lot of
opportunities for the aluminum. With research and development in the manufacturing
and design it could be highly used in the automotive bodies. Hydro forming
technology that utilizes hydraulic pressure to form tube and sheet materials into
desired shapes inside die cavities, offers several advantages when compared to
conventional manufacturing, based on stamping and welding.
However, there are several drawbacks which hold the growth of aluminum in the
automotive industry such as high energy consumption during production of aluminum,
cost of aluminum as it is nearly three times as expensive than steel. Also there is a
need foe high investment in the development of new tooling methods.
These drawbacks have made the industry to look into various other lightweight
materials such as composite structures rule that right material with the right
technology in the right place can exploit full use from the positive properties of each
material and can ensure maximum benefits [53]
.

Carbon Fibres are increasingly gaining importance as it is lighter than aluminum, but
due to cost and technology their growth is very slow. Also the development of ultra
light steel which lighter than conventional steel and exhibits the properties of
aluminum could be a threat to the use of aluminum in the automotive bodies.
After discussing the strengths, weaknesses, opportunities and threats of aluminum, the
challenges of aluminum can be summarised as follows for its usage in automotive
bodies.
1. The aluminium extraction process offers great challenge as it the prime reason for
the high material costs and thus there is huge need of improvement [55]
.
2. The aluminium part design needs to be enhanced to take good advantage of its
lightweight property.
3. The manufacturing methods of aluminium parts needs to be understood ,and the
process needs to evaluated and optimized in order to use aluminium in mass
production of automotive bodies.
4. Though aluminium offers advantage of recycling after its end of life, it is
necessary to identify an effective recycling procedure.
It is verified that aluminum can be used to replace steel, iron, and copper for various
parts in a car, but weight reduction in most cases has increased cost. However, the fuel
efficiency and environmental legislation pressures may prove to be more significant
than the cost barrier.
The joining techniques of lightweight material such as aluminum will be evaluated
and their advantages and challenges will be drawn and compared.

3.3 LIGHTWEIGHT JOINING TECHNIQUES
Despite significant advantages of aluminium over steel, the lack of standardised
manufacturing and assembly process impede use of aluminium in body structures of
passenger cars. The joining techniques have to be evaluated and developed in order to
use aluminium parts in mass produced vehicles.
There are several developing methods which have shown their potential and also have
been used by some of the automotive companies in manufacturing aluminium
intensive vehicles, such as:
The Audi A2 and A8 models use aluminum space frame construction that is welded,
bonded and riveted for structural strength. The Audi A2 is joined using about 30
meters of laser weld seams, 20metres of MIG (Metal Inert gas) - welded seams and
around 1800 rivets per car [65]
. At the same time the process are 85% automised which
could be comparable to a conventional steel body construction [66]
. The methods
adopted allow up to 300 cars to be built in a day.
The Jaguar XJ8 uses several different types of aluminum parts to construct the car's
monocoque body, here around 3200 self-piercing rivets and 120 meters of adhesives
are used to assemble the inner body structure, and exterior panels are bolted [67]
.
2006 Chevrolet Corvette Z06 uses aluminium space frame consisting of castings,
extrusions and stampings. It uses SynroPuls MIG welding, laser welding and self
piercing riveting metal joining technology [49]
. SynroPuls MIG welder allows for a
spatter-free weld with less porosity, laser welding is used on the tunnel assembly to
provide a structural joint, self piercing riveting is used to join stamped aluminum
components and provides a secure sealed mechanical joint for the space frame.
Clearly there are joining technologies which are capable of utilising the lightweight
advantage of aluminium as well assist in further weight reduction by reducing of spot
welds. First the various joining methods will be studied and evaluated and finally
corresponding results and conclusions can be drawn and a concept for the
management of this lightweight joining can be studied. The process evaluated are

resistance spot welding, laser welding, Metal inert gas welding, adhesive bonding, self
piercing riveting and friction stir welding.
3.4 RESISTANCE SPOT WELDING
RSW is the most commonly employed joining method for steel sheet in the
automotive industry [24]
and is used in 70% of joining of automotive bodies [58]
. Its
principle benefits are high speed and low cost operation, plus the ability to weld a
wide range of joint configurations with the same gun.
The figure 3.4 exhibits the resistance spot welding process where pressure is provided
by clamping the overlapping sheets between two electrodes followed by passage of
current between the electrodes and thus joining the sheets at their interface by
resistance heating followed by local fusion.
Figure 3.4 Principle of spot welding process [9]
A typical passenger car contains between 2000 to 5000 spot welds [7, 58]
, and nearly
30% of the welds are needed to maintain design requirements as the process is
inexpensive compared to the cost of inspection and thus these spot welds increase the
weight of the vehicle.
Moreover, the problems with this process are not only with over- welds, but even the
life of the electrode is a concern. Pick-up of aluminium on to the tip and rapid wear [9]

are the two main reasons for the short life of spot welding electrodes along with high
welding currents and surface finish.
Though the surface finish of the welds is good as a result of no weld spatter and arc
flash the process requires a good surface preparation of the part to be assembled.
There is also a possibility of galvanic corrosion during welding of some dissimilar
metals [10]
.
The joining the process as shown in figure 3.4 clearly illustrates alignment of parts to
give good contact at the joint area for better weld [10]
and requirement of both sides of
the joint, thus restricting its use in space frame technologies [57]
.
However the resistance spot welding process has been a well established process and
used in most of the automotive manufactures bodies due to very lost cost, high speed
of process, and ease of automation. It produces a clean, high quality weld with very
low distortion, while there is a small heat affected zone created [10]
. High production
rates possible due to short weld.
3.5 LASER WELDING
Laser welding is used increasingly in both the automotive and aerospace industries for
the welding of a range of materials. Laser welding is an important technology in the
assembly of automotive components, it is used in welding gear parts, and weld
tailored blanks for body stampings and assembly welding of panels onto the body-in-
white [13]
.
Laser welding involves focusing the beam of a high power laser on the joint between
two work pieces and this high power density narrow beam of light generates the heat
for fusion as shown in figure 3.5.

Figure 3.5 Schematic Laser welding process [20]
As shown in figure 3.5, the energy produced by the laser is very concentrated, it has
an intensity of power input at the weld surface of around 106
W/cm2 [20]
which
produces a weld with high depth to width ratio and with minimal thermal distortion.
There are various types of lasers available for different applications such as: CO2, Nd:
YAG (Neodymium: Yttrium -Aluminum- Garnet laser), Nd: glass, ruby and excimer
[10]
. However, in automotive applications the CO2 and Nd: YAG lasers are being used.
Automotive manufacturers are increasing the use of laser welding due to its features
like: high productivity, continuous welding process and standardized tools. The laser
welding shows signs of enhanced body rigidity and collision safety performance[14]
, it
assists in weight reduction vehicles by eliminating the spot welds as wells as reducing
the number of parts and eliminates restriction on shapes of parts made for
welding[14,17]
.
One of the earliest applications of laser welding is the Audi A2 which has some 30
metres of laser welds in its bodywork[9]
,other companies such as Nissan has used
YAG laser welding for the body in white and applied to the joint of roof and body side
of car[15]
.

At Volvo where CO2 and Nd : YAG laser systems are incorporated into the body line
for the 850 series vehicles[57]
, the advantages of greater body stiffness, material
savings and weight reduction are further complimented with high flexibility of the
process to new designs.
Laser welding was used in the manufacturing of 2006 Chevrolet Corvette Z06
aluminium space frame where it was used for welding geometrically constrained
regions such as tunnel subassembly. The laser system consisted of fours components:
laser supply, assembly tooling, welding optics, and robotics as shown in figure 3.6.
Figure 3.6 Laser welding Cell [11]
Here a fibre optic cable delivers power to the Highyag optics controller, a pressure
wheel is used to control the distance between the material and the optics lens and an
aluminum wire feed to the Fanuc robot is used to add filler material to the laser weld
thus creating a hybrid laser weld.
There is vertical tooling used for optimisation of cycle time and floor space, and the
laser-welded subassembly maintains constant weld seams along die stamped
components to produce increased structural integrity[11]
.

In Toyota laser welding has been applied for welding roof, luggage compartment
door, exterior and floor panels and door openings to enhance the vehicle performance
and productivity. Figure 3.7 shows an example of laser welding system introduced at
Toyota Motor Corporation for welding vehicle body. A laser oscillator with a very
high output and wavelength of 1.06 micro meters enables optical fibre transmission
and by leading the oscillator to the process head installed on a multi-indirect robot
makes laser welding suitable for welding three dimensional shapes.
Figure 3.7 Example of Laser welding process at TMC [14]
The development of Laser welding applications in automotive industry can also be
attributed to its benefits in fabrication of tailored blanks, which is enabling steel
vehicles to achieve significant weight reductions. Laser welding requires only one side
access to produce sound structural welds that meet the requirements demanded by
automotive manufacturers.
Laser welded blanks are being extensively used for increasing dimensional accuracy
through the use of fewer panels, reduction in the number of parts thus lowering the
assembly costs, for production of a stiffer, quieter, more stable vehicle[13]
.

It is clear that laser welding is rapidly developing its importance in the automotive
industry. Design and quality aspects are summarised displaying the advantages and
limitations in the laser welding process.
The design and quality aspects of laser welding are explained as follows:
 Path to joint area from the laser must be a straight line. Laser beam and joint
must be aligned precisely. And the opening between panels must be strictly
controlled to obtain high quality weld [12, 15]
.
 Normally an inert shielding gas is required to reduce oxidation [10]
.
 The reflectivity of the work piece surface plays a crucial role in the quality. Dull
and unpolished surfaces are preferred [10]
as high reflectivity inhibits the
absorption of laser and its high conductivity disperses heat rapidly leading to
loss of energy and thus increasing the energy requirement for the process [58]
.
The laser welding process has advantages such as:
 The driving force of the process is high amount of power required and this
allows high speed welding with minimal thermal distortion [15]
. The weld rates
range from 0.25–13 m/min for thin sheet, however the overall production rate is
moderate [10]
.
 The process induces very little thermal distortion as a result of a lower overall
heat input. This is due to the highly focused, high energy density beam which
rapidly heats a very a narrow and sharp area, and produces a fine weld bead and
a narrow Heat Affected Zone [57]
. The overall heat input ensures relatively easy
assembly precision thereby improving the formability of welded sheet
component [12, 58]
.
 One of the main advantages of laser welding is that it is a one side welding
process which enables joining of complicated and varying shapes according to
vehicle design which otherwise was difficult using spot welding gun and prevent
designing of new welding guns for new vehicles produced and requires no
consideration to be given for providing work space for a welding gun in panel
configurations [12, 14, 15, 17]
.

 Laser systems are can be subjected to a high degree of automation. In particular,
the ability to transmit the beam of an Nd: YAG source along fibre-optic cables
provides ultimate flexibility through manipulation of a remote laser head by
robot. The robot allows the laser head to be manoeuvred around complex
geometries [57]
. It is also possible to perform many operations on the same
machine by varying process parameters however the tooling and equipment cost
is high [10, 19]
.
 The welds are generally of a high quality and surface finish is good.
 The process allows joining of dissimilar materials which provides an advantage
over the other process.
The disadvantages of laser welding are:
 The equipment and tooling cost is very high along with risk associated
accidental injuries from laser beam [19]
. There is a need for complete enclosure
of the laser equipment with restricted personnel access and also requirement of
skilled labour.
 Limited penetration depths particularly with aluminium restricts the use of lasers
in some areas of the space frame such as reinforced areas[57]
, as maximum of 2–
6 mm depth is achievable with Nd : YAG lasers (depending on the power of the
system), and about 6 mm for CO2 lasers.
 Laser welding has been shown to experience problems of crack sensitivity in
welding aluminium [57]
. Also there have been problems encountered by
introducing filler wire into the weld-pool
 It is likely that due narrow fusion zone the process may not tolerate gaps greater
than 10% of material thickness between the abutted edges of the components
being joined [57,15]
.
 Porosity defects in the welds are caused by hydrogen from the environment,
dissolved in the parent metal or contained in the oxide film. Thus to counter this
problem careful surface preparation including pickling and scraping, gas
shielding are needed [9]
.

3.6 METAL INERT GAS (MIG) WELDING
The metal inert gas welding is a process based on creation of electrical arc between
the welding torch and the work piece as shown in figure 3.8[20]
. The parent metal is
melted and the weld created with the continuous feed of the wire acts as the filler
metal [10]
.
Figure 3.8 MIG welding process [9]
The weld area is shielded with a stable stream of argon or CO2 to prevent oxidation
and contamination. The intensity of the power input of this process is around 103
W/cm2, which produces a weld of small depth and medium width.
Metal Inert Gas Welding has been used for the welding of aluminium alloys in the
automotive industry as in the case of Audi A2 and A8 models for the manufacturing
of aluminium space frame.
The advantages and limitations of Metal inert gas welding can be listed as follows:
Advantages:
 It is possible to join nearly all weldable materials unalloyed and alloyed steel, as
well as CrNi steel are welded with appropriate welding, other materials such as
aluminum, magnesium, and nickel based materials, copper, titanium etc. require
MIG welding with inert gases [68]
.
 This process is highly efficient (60-80%) [20]
, welding speed is high with
sufficient seam quality. Welding speed varies from 0.2 m/min for manual
welding to 15 m/min for automated setups [10]
.

 Well suited to traversing automated and robotic systems, it is possible to process
all levels of complexity in welding and also possible to weld unequal thickness
materials [10]
.
 Typical joint designs possible using MIG welding are butt, lap, fillet and edge,
furthermore MIG welding is excellent for vertical and overhead welding
 Surface finish of the weld is good, tolling costs and equipment costs are low
compared to laser welding.
 It produces high joining strength and process can be used in wide range of
applications.
Design Considerations and Limitations:
 Energy density and welding speed is lower compared to laser welding process
thus causing high heat input to the work piece and consequent thermal
distortions [20]
.
 The process requires skilled labour but, the process can be easily automated.
 The process uses shielding gases such as pure CO2 or argon for different
materials, pure argon is used for aluminum alloys.
 One of the important considerations is to design the part which gives access to
the joint area, for vision, electrodes, filler rods, cleaning, etc and sufficient edge
distances should be designed to avoid welds meeting at the end of runs. There
should also be a provision for the escape of gases and vapours in the design [10]
.
 Joint edge and surface preparation is important for good quality weld,
contaminants must be removed from the weld area to avoid porosity and
inclusions.
 A heat affected zone is always present and some stress relieving may be required
for reinstatement of material’s original physical properties.
3.7 SELF – PIERCE RIVETING (SPR)
Self pierce riveting is a mechanical cold joining process used to join two or more
overlapping sheets. It can be used to join wide range of materials such as uncoated and
pre painted steels, aluminium alloys and combination of dissimilar materials. Its

importance as effective joining is increasing in the automotive industry with wide
range of applications in multi-material body production and for production of
aluminum body structures.
Figure 3.9 Self pierce riveting process [27]
The self pierce riveting process is illustrated in figure 3.9. The tubular rivet is pierced
through the upper sheet of material, the rivet expands in the lower sheet, usually
without piercing it [21]
, to form a mechanical interlock. This process does not require a
predrilled hole, however from the figures 3.9 it is clear that both sides of the material
have to be supported using a die.
Since the process involves piercing of the rivet in to the material, the process requires
quite large setting forces (40 KN) [24, 21]
. For this reason, a C-frame structure is
necessary in order to withstand the riveting force [27, 21]
.
The process has been used in roof panels, dash panels and in joining extrusions and
die castings [12]
.The wide application of the process has been in aluminum space
frames by addition of corrosion inhibiting coating to the steel rivets to prevent
galvanic corrosion [24]
. The Audi A8 and A2 models have used more than 1800 self
piercing rivets with automation level of the process increasing from 25% in A8 to 85
% in A2[65]
.
Jaguar also uses this technology in manufacturing its aluminum intensive car and has
used 3200 rivets with 100% automation in its XJ model [67]
. The speed of application
of rivets has been 5 seconds per rivet using the automation technology as used in

manufacturing of aluminum space frame for the Chevrolet Corvette Z06[11]
. Lotus also
used self-piercing rivets in the construction of a light-weight chassis for the Elise. In
joining the aluminium extrusions which make up the chassis structure, Lotus made
extensive use of adhesive bonding, with rivets providing secondary protection against
peel [21]
.
The advantages and challenges of this lightweight joining technology can be
summarised as:
Advantages and Benefits:
1. The SPR joints have the ability to join multilayer and multi-material stacks with
good shear and peel strength.
2. The process is quiet and does not involve heat input so high assembly precision
can be attained and the process is safe as there are no fumes, emissions or high
currents [21, 12, 26]
.
3. The process setup is simple with low power consumption.
4. The SPR involves low investment with low operating costs and long equipment
service and tool life [21]
.
5. Ease of automation — the equipment can be adapted for use with a robot, and
can be easily integrated into fully automated, high-speed assembly lines.
6. The fatigue strength and other mechanical properties of the joint have good
results and it is found that fatigue strength of SPR is double to that of RSW.
7. This process like other process does not have problems with respect to
inspection. The joints can be easily inspected by simple measurements and
visual checks [21]
.
8. SPR guns require water cooling and use 10% of power of spot welding guns [28]
.
In spite meeting most requirements needed by the automotive industry the process has
few challenges and design considerations which needs to tackled such as:
1. One drawback of using steel rivets in an aluminium car is the need for separation
of the two materials as part of recycling at the end of vehicle life [24]
. However
aluminium rivets can be developed and used as in aerospace industry but the cost
of rivets would be significantly high.

2. Since the process require high setting forces (typically around 10 times to that
required by spot welding), the size of the guns needs to be larger and additional
robot carrying capacity is required to access certain areas.
3. The significant disadvantage of this process is the need for dual access which
restricts its use in some areas of space frame manufacturing.
4. Their could be weight involved in the process as it has been noticed that nearly
2000 to 4000 rivets are used in a single vehicle. Also there are bulges and
indents associated which may not give an aesthetic advantage.
5. It has been observed that despite the use of passive coatings to prevent
corrosion, surface irregularities or crevices occur as a result of the deformation
process which could allow corrosion to occur [21]
.
6. Also to ensure sufficient joining strength the rivet insertion and stack thickness
play an important role. To avoid low interlock strength the lower sheets have to
be thicker than the upper sheets in the stack [12]
.
3.8 ADHESIVE BONDING
Adhesive bonding can be defined as chemical joining of two surfaces. It is one of the
important joining methods which help in achieving significant weight reductions. The
primary advantage of this process has been it can complement other joining methods
and help in better stiffness and low weight.
Typically spot weld bonding reduces the number of spot welds on the vehicle by 50%
[22]
thus gaining considerable weight savings. Also adhesively bonded designs have
shown good resistance to dynamic fatigue, body stiffness, crash performance and
improved corrosion resistance compared to other methods [22]
.
Figure 3.10 Dynamic and fatigue properties of various joining procedures [22]

Figure 3.10 clearly shows that only adhesively bonded joint show the best dynamic
fatigue performance compared to other joining methods, even better than spot-weld
bonded connections. However the use of only adhesive bonding as a joining procedure
has not gained acceptance due to belief that they tend to loose their performance and
properties over time depending on their mechanical loading and environment exposure
[23]
.
The benefits of adhesive bonding have been demonstrated by a number of car
manufacturers in concept cars and low volume niche products, e.g. Jaguar’s XJ,
Ford’s AIV, Rover’s ECV3 and the Lotus Elise [21]
.
The advantages of adhesive bonding are:
 It complements other joining processes and offers high operation durability and
less corrosion and gives good noise, vibration and harshness properties at high
application speeds.
 Adhesive bonding offers improved joint stiffness compared to mechanical
fasteners or spot-welds [21]
. It has a uniform stress distribution because it produces
a continuous bond rather than a localised point contact.
 There is no metallurgical damage or welding scars and smooth joint produced
reduces stress concentrations at the joint edges thereby providing good fatigue
resistance
 It is possible to join dissimilar and otherwise incompatible materials. Also allows
greater flexibility in design of the components as it can access all areas [70]
.
 Adhesive bonding has tended to be regarded as a comparatively low cost process
in terms of equipment.
The limitations of the process are:
 Environmental concerns and the health and safety hazards involved in the use
of most adhesives implies significant costs in providing adequate fume
extraction, protective clothing and adequate provision for fire protection
storage.

 The use of adhesive has been restricted to volume production with one of the
likely reasons to high maintenance of the adhesive dispensers which require
regular cleaning and routine maintenance [21]
.
 The need for jigs and fixtures to support joints during adhesive curing presents
another significant production problem and accounts for high costs [10]
.
 The process requires pre-treatment of the surface, it is necessary not only to
remove contaminants such as lubricants and oils, but also to provide the
intimate contact needed for the adhesive to bond successfully with the adhered
surface.
 Also adding to poor peel strength there is no reliable non-destructive testing
(NDT) technique for inspection of adhesively bonded joints [21]
. This inability
to reliably monitor bond quality during production, coupled with uncertainty
with regard to the long term durability and weather ability of adhesive bonds in
service, are significant issues which continue to hinder this joining process.
3.9 FRICTION STIR WELDING
Friction stir welding is a new solid state joining process mainly used in welding
lightweight materials such as aluminum alloys and can be applied to magnesium,
titanium, copper and lead, and aluminum-magnesium joints[31]
.
In this joining process, heat for creation of joints is caused by rubbing of a non-
consumable third body on the work piece material and by deformation produced by
the passage of the third body [30]
(tool).Figure 3.11 indicates the working principle of
friction stir welding process where continuous joint is produced as the tool moves
over the work piece material.
The important parameter of this process is the wear resistant tool which has two
components: pin and shoulder. Pin protrudes from the lower surface of the tool and
shoulder is relatively large in diameter as seen in figure 3.11.

Figure 3.11 Friction stir welding principle [38]
Welding is initiated once the pin is fully inserted in the material and shoulder is in
intimate contact with the top surface of work piece material. Heat is generated by the
shoulder rubbing the material surface under apparent force and thus softening the
work piece. This heat is then carried by the pin across the bond line producing a
continuous joint [30]
.
This process operates below melting temperature of the work piece material providing
superior weld joints free from blowholes and porosity [35, 31]
.The process can be used
to join dissimilar aluminum alloys without any shielding gas during the welding
process.
Friction stir welding can be applied to linear and longitudinal welding in all three
dimensions [35]
, it has been applied to stitch weld aluminum sheet metal for automotive
closure panels and has shown characteristics to be used in wheel rims, engine cradles,
tubular nodes and tailored blanks.

The table 3.1 lists out the advantages and challenges of this joining process.
Advantages Challenges and Limitations
Superior weld quality with minimal
distortions [33]
.
Relatively slow speed of operation
Improved fatigue and fracture properties
of friction stir welds
Support and clamping required for
accuracy as it involves high pressures
Ultimate tensile strength and yield
strength of the weld are significantly
higher than other joining process over a
broad range of temperature and thickness.
Joining of high temperature materials
offers great challenge.
The process is relatively inexpensive There is an end hole left at the star and
stop points of the weld which must be
filled after processing.
It has good corrosion resistance, and is
free from weld porosity and blow holes.
Post-process heat treatment is required to
restore some of the original properties of
the parent metal to the joint area.
It is a clean process with excellent surface
appearance of the weld bead.
Flexibility with automation of the process
seems to be one of the major limitations.
It consumes relatively little energy and is
essentially low-maintenance process.
The process is capable of joining material
up to 12 mm thick.
Table 3.1 Friction Stir Welding
Derivative of friction stir welding: friction stir spot welding (FSSW), also called as
spot friction welding or friction spot joining has rapidly developed and been used by
automotive industry as in Mazda RX-8 which uses FSSW in rear doors and bonnet to
avoid spatter and gain significant reduction in energy consumption compared to
resistance spot welding[36,40]
. This process has also been applied to weld aluminum on
steel by Mazda to the trunk lid of its MX – 5 sports cars [42]
.
The spot friction joining process works on the same principle as friction stir welding
except for there is no lateral movement of the tool during the welding process. Figure
3.12 shows the schematic representation of spot friction joining process.

Figure 3.12 Friction stir spot welding process [43]
The process can be divided into 4 stages: rotate, plunge, hold and release as displayed
in the figure 3.12. The rotating pin is plunged into the sheet material and kept at the
same position. High pressure is applied between the pin and the anvil to hold the work
piece together, thus as a result of frictional heat materials are softened and brought
together to form a permanent point joint [43]
.
3.10 ANALYSIS
In this section the technology drivers surrounding the lightweight structures were
discussed.
The two weight reduction strategies: replacing the materials of high specific weight
with lower density materials and optimization of the joining techniques were studied.
The general classification for material selection in automotive applications and the
potential of aluminum to be used in car bodies were analysed with the help of SWOT
analysis.
A comprehensive study of lightweight joining processes such as: resistance spot
welding, laser welding, metal inert gas welding, self piercing riveting, adhesive

bonding and friction stir welding was done. The advantages, limitations, design
considerations of each of the joining methods were explained.
Table 3.2 below summarises the joining process discussed, and tables 3.3, 3.4 and 3.5
compare the joining process based on performance and safety, automation and cost,
and process time and operation requirement respectively.
Resistance Spot Welding:
Joining occurs as a result of fusion at the
interface of the sheets by the passage of current
between the two electrodes clamping the
overlapping sheets on either side.
Laser Welding:
High power laser beam is focussed on the
joining area between the two work pieces and
this high power density narrow beam of light
generates the heat for fusion.
MIG Welding:
This process is based on creation of electrical
arc between the welding torch and the work
piece, the parent metal is melted and the weld
created with the continuous feed of the wire
which acts as the filler metal.
Self Piercing riveting:
It is a mechanical cold joining process where
tubular rivet is pierced through the upper
sheet of material and it expands in the lower
sheet, usually without piercing it to form a
mechanical interlock.
Adhesive Bonding: Adhesive bonding can be
defined as chemical joining of two surfaces.
The primary advantage of this process has been
it can complement other joining methods and
thus help in better stiffness and low weight.
Friction Stir Welding:
In this joining process, heat for creation of
joints is caused by rubbing of a non-
consumable third body on the work piece
material and by deformation produced by the
passage of the third body .
Table 3.2 Summary of joining process

BASED ON PERFORMANCE AND SAFETY:
Sl
No.
Joining Process
Type
Corrosion
Resistance
Strength Joint Quality Safety And Inspection Energy
Consumption
1. Resistance Spot
Welding
It shows poor
resistance to
corrosion.
Moderate strength but
decreases with the
decrease in condition
of electrode
Clean and good quality
joint can be achieved, but
small heat affected zone
is present.
The process has
established safety and
inspection methods.
Major drawback is
high power
consumption
2. Self Piercing
Riveting
Inspite of coatings,
surface
irregularities occur
as a result of
deformation which
could assist in
corrosion
Good peel and shear
strength and fatigue
strength of SPR is
found to be double to
that of RSW.
Rivet insertion and stack
thickness play an
important role.
The process is quiet and
safe as there are no
fumes, emissions or high
currents involved. The
joints can be easily
inspected by simple
measurements and visual
checks
The process setup is
simple with low
power consumption
however heavy duty
robots are required.
3. Adhesive Bonding This technique
provides excellent
resistance to
corrosion.
Adhesively bonded
joints show the best
dynamic fatigue
properties compared
to other joining
process but are
inherently weak in
peel strength.
To provide good joint
intimate contact is
required between the
adhesive and adhering
surface.
Excellent body stiffness
and improved noise,
vibration and harshness.
However there are safety
and environmental
concerns associated with
use of adhesives.
It is a low energy
process.
Table 3.3 Comparison of the joining techniques based on performance and safety continued to next page.

Table 3.3 Comparison of the joining techniques based on performance and safety
Sl
No.
Joining Process
Type
Corrosion
Resistance
Strength Joint Quality Safety And Inspection Energy
Consumption
4. Friction Stir
Welding
It has good
corrosion
resistance, and is
free from weld
porosity and blow
holes.
Ultimate tensile
strength and yield
strength of the weld
are significantly
higher than other
joining process over a
broad range of
temperature and
thickness.
Superior weld quality
with minimal distortions.
It is a clean process with
excellent surface
appearance of the weld
bead
Safe process. It consumes
relatively little
energy.
5. Metal Inert Gas
Welding
It exhibits good
corrosion
resistance
properties
It produces high
joining strength
Joint edge and surface
preparation is important
for high quality weld,
contaminates must be
removed from the weld
area to avoid porosity
and inclusions
The process requires the
parts to be designed such
that there is access for
non destructive
inspection
Energy density and
welding speed is
lower compared to
laser welding
process.
6. Laser Welding It exhibits good
corrosion
resistance
properties
It offers very good
strength and body
stiffness with very
good noise, vibration
and harshness
properties
The welds are generally
of a high quality and
surface finish is good,
however porosity defects
are likely due to
hydrogen from
environment.
Very good crash resistant
performance but risks of
accidental injuries from
laser beam are
associated.
Very high energy
process. Reflective
materials further
increase the energy
requirement of the
process.

BASED ON AUTOMATION AND COST:
Table 3.4 Comparison of the joining techniques based on automation and cost
continued to next page
Sl
No.
Joining Process
Type
Automation Flexibility Operating And Maintenance
Cost
Tooling And Equipment
Investment
1. Resistance Spot
Welding
High automation flexibility and developed techniques
and it is likely to achieve 100% automation in joining
aluminum BIW
The operating and maintenance
costs are moderate
Low tooling and equipment
costs are one of the major
advantages of the process
2. Self Piercing Riveting The process shows ease in automation, and the process
can be easily integrated into fully automated, high speed
assembly lines but require large size guns as the process
due high setting forces involved and additional robot
carrying capacity is required to access certain areas.
The degree of automation of the process has increased
from 25% when it was introduced in Audi A8 to 85% in
1999 and now 100% of the process is automated for
production of Jaguar XK.
costs are low but the high cost
of rivets is one of the biggest
drawbacks of the process.
Low investment and long
equipment service and tool
life.
3. Adhesive Bonding The use robots for the application of adhesives have not
been commonly used because of lack of NDT for quality
testing of the joint. Manual application is usually
preferred as it ensures perfect laying of adhesive to the
point of contact, as well as the precise path of delivery.
High maintenance required for
adhesive dispensers.
The cost involved in joint
preparation could be high,
however direct labour and
finishing costs are
comparatively low.
It is regarded as the low
cost process in terms of
equipment however the
tooling costs are low to
medium due to requirement
of jigs and fixtures in the
process.

Table 3.4 Comparison of the joining techniques based on automation and cost
Sl
No.
Joining Process
Type
Automation Flexibility Operating And Maintenance
Cost
Tooling And Equipment
Investment
4. Friction Stir Welding The flexibility with and degree of automation achievable
in this joining technique is very low.
Low maintenance costs and
operating costs.
The equipment and tooling
costs are moderate to high.
4. Metal Inert Gas
Welding
It is well suited to traversing automated and robotic
systems and possible to process all levels of complexity.
costs are moderate to high due
requirement of skilled labour
and shielding gases used in the
process.
Tooling costs and welding
costs are less compared to
laser welding process but
the equipment cost varies
on degree of automation.
5. Laser Welding Laser systems can be subjected to a high degree of
automation. In particular, the ability to transmit the
beam of an Nd: YAG source along fibre-optic cables
provides the ultimate flexibility through manipulation of
a remote laser head by robot. The robot also allows the
laser head to be manoeuvred around complex geometries.
The costs are high due to
requirement of high energy,
highly skilled labour and
normally an inert shielding gas
is required to reduce oxidation.
The equipment and tooling
cost is very high and there
is a need for complete
enclosure of the laser
equipment with restricted
personnel access.

BASED ON REQUIREMENT AND PROCESS TIME:
Table 3.5 Comparison of the joining techniques based on requirement and process time
continued to next page
Sl
No.
Joining Process Type Process Time And Production
Quantity
Material Compatibility Joint Accessibility / Configuration
1. Resistance Spot Welding The process time for RSW can vary
from 1.2 to 1.6 seconds depending on
the material thickness.
This process has been used in mass
production assembly lines.
Any material combination can be
welded and maximum sheet
thickness of 6mm to a minimum
of 0.3 mm can be joined
Can be used in joints not accessible by
other techniques but requires both sides
to produce a good quality weld.
2. Self Piercing Riveting The process time of SPR was found
1.3 seconds for all types of joints
configurations.
The SPR joints have the ability to
join multilayer and multi-material
stacks. Maximum section
thickness of 200mm to minimum
of 0.25 mm can be joined.
Both sides of the part to be joined are
required which restricts its use in some
areas of space frame manufacturing.
To avoid low interlock strength the
lower sheets have to be thicker than the
upper sheets in the stack.
3. Adhesive Bonding The time of curing dictates the
production rate. It was reported that
as long as 50 minutes of curing is
necessary for Lotus Elise and 30
minutes is required for Aston Martin
DB9.
It is possible to join wide range of
materials and even dissimilar
materials with proper selection of
adhesive. It can bond sheets from
0.05mm to about 25 mm of
thickness.
It can be used to join all complex joints
not practically accessible by other
methods.

Table 3.5 Comparison of the joining techniques based on requirement and process time
Sl
No.
Joining Process Type Process Time And Production
Quantity
Material Compatibility Joint Accessibility / Configuration
4. Friction Stir Welding Relatively slow speed of operation,
and the process time for joining thick
sheets is very high of up to 9 seconds.
The process can be used to join
dissimilar aluminum alloys
without any shielding gas during
the welding process; however
joining of high temperature
materials offers great challenge.
Friction stir welding can be applied to
linear and longitudinal welding in all
three dimensions but requires the part to
be ideal position, supported by jigs and
fixtures.
5. Metal Inert Gas Welding This process is highly efficient,
welding speed is high with sufficient
seam quality. Welding speed varies
from 0.2 m/min for manual welding
to 15 m/min for automated setups.
It is possible to join nearly all
weldable materials of unequal
thickness, however dissimilar
materials are difficult to weld.
Typical joint designs possible, also it is
excellent for vertical and overhead
welding, however requires space to
access the joint area for vision,
electrodes, filler rods, cleaning.
6. Laser Welding The driving force of the process is
high amount of power required and
this allows high speed welding with
minimal thermal distortion. The weld
rates range from 0.25–13 m/min for
thin sheet.
The process allows joining of
dissimilar materials but has
limited penetration depths of
approximately 6mm.
It is a one side welding process which
enables joining of complicated and
varying shapes according to vehicle
design and requires no consideration to
be given for providing work space for a
welding gun in panel configurations, but
requires proper alignment of joint area.

PROPOSED OUTLINE MODEL
4.1 INNOVATION MODEL
It is clear and evident that in the current economical and market situation, for a
company to competitive, it has to produce and come up with innovative and
technologically advanced products on a regular basis. It has to not only look out for
new technologies but, also optimise and develop the existing ones.
A technology management or innovation development method has been developed
based on the product development and technology management techniques innovation
models discussed in sections 2.5 and 2.7 respectively.
Figure 4.1 shows the technology management technique which could be used by a
technology manager in an organisation to keep a track and look out for of new and
upcoming technologies and to optimise the existing ones.
The model developed will be discussed and explained in the context of weight
reduction which is currently one of the promising technologies in the automotive
industries.
The Innovation management model as shown in figure 4.1 can be thought in the form
of funnel with top forming the technological idea creation, the centre would be the
product development and bottom is exploitation. The different phases are as explained
below

Figure 4.1 Innovation Management Model
Learn,
Analyse &
Plan
Design,
Evaluate &
Optimize
Validate,
Implement &
Launch
Generate
Impulse /
Feedback
SEARCH / DETECT PROCESS SIGNALS
Market Trends – Customer, Industrial, Legislation, Sociodemorgraphic
Technology Life Cycles – Exploiting discontinuities
Research and Patents Database
Find drivers and thus products. Ex: Safety –
Occupant production systems, Collision Protection
systems
SELECT AND SCREEN
Products
Life cycle analysis, other tools: Rating
matrix, SWOT analysis
PRODUCT
DEVELOPMENT
OR
TECHNOLOGY DEVELOPMENT
SUSTAIN AND COMMERCIALIZE
Maximise the value out of the technology
KNOWLEDG
E
&
RESOURCES
CONTROL
&
TRACK
PROGRESS

.Phase I:
SEARCH / DETECT & PROCESS SIGNALS:
Search Signals:
The time for development of an idea into product delivery varies. It can take several
stages to spring the product in the market so it is very important that the signals are
sensed at an early stage. The following techniques can be used for constantly
searching signals.
 Analysing the life cycle of a technology as discussed in section 2.4.
 Evaluating the global market trends (discussed in section 2.2) such as customer
trends, regulations, etc.
 The research and patents database help in understanding the scientific
developments which can be incorporated to develop new technologies or
enhance the existing ones.
Process Signals:
The signals generated are processed resulting in various drivers. The automotive
regulations and customer trends have resulted in technology drivers such as
environment, fuel efficiency, safety as discussed in section 2.3. The drivers’ further
lead to product technologies such as fuel efficiency and environmental drivers could
result in technologies such as:
 Hybrid technology
 Weight reduction
 Fuel Cell technology
Phase II:
SELECT AND SCREEN:
The decision to choose on which technology to develop is in important part, hence a
thorough analysis the technologies has to be done. The various tools that can be used
such as SWOT analysis, product matrix (discussed in section 2.8), rating matrix etc.

Weight reduction is a promising technology to meet fuel efficiency, environment
drivers and thus the global automotive trends. There are various strategies for weight
reduction of the vehicle such as:
 Selecting lighter or lower density materials
 Optimizing or improving existing designs
 Combining or eliminating parts, assemblies, and/or their function
 Removing content or features from the vehicle
 Revising manufacturing or assembly operations
Phase III:
TECHNOLOGY DEVELOPMENT OR PRODUCT DEVELOPMENT:
This phase has been divided into 4 stages as shown in the figure 4.1 and is supported
by knowledge database and resources, and a tracking and control system to check the
progress of the development stage. Control and planning is a vital part of the product
development process and can be done with the help of simple tools such as IBR
(Intensive business tracking) sheets, having regular meeting to track the progress
according to the plan.
Stage1: This is mainly the strategy development stage or problem definition stage.
This stage involves understanding the selected product technology, examining the
various factors involved with the product development, analysing the technological
gaps and thus preparing a project proposal and plan to accomplish the requirements of
the problem.
In this project the lightweight joining process is selected and studied. The challenges
and benefits of the six lightweight joining processes such as RSW, laser welding, MIG
welding, SPR, Adhesive Bonding and FSW were identified and studied (sections 3.4,
3.5, 3.6, 3.7, 3.8, 3.9 respectively). The proposal for comparing and evaluating the
criteria for selection of joining process is planed.
Stage2: This is the serious design and evaluation stage where the proposed plan of
project is developed and analysed. Thorough analysis of the technology based on
product requirement s is done. The product or process is developed and optimised.

In this case the six joining processes were compared on the basis of performance and
safety, automation and cost, and process time and operation requirements displayed in
tables 3.3, 3.4, 3.5 respectively. It is found that it is very difficult to assert a single
joining process for the automotive body joining; there are various factors which play
an important role in the selection of the joining process such as:
 Technical Performance Criteria: quality, corrosion resistance, strength, etc.
 Equipment and Tooling Cost
 Operation and Maintenance Cost
 Operation Flexibility: Material, Part configuration
 Safety
 Process time/speed
 Degree of automation
Figure 4.2 Process Selection Criteria
Figure 4.2 exhibits the factors affecting the process selection criteria, and as discussed
it is difficult to state which of the factors is of most importance, this purely depends
on the organisation and product requirements. The factors have to be synchronised in
order to meet the product requirements as stated in the first stage.
Process
Selection
Criteria
Degree of
automation
Operation
cost
Flexibility
Speed
Initial Cost
Safety
Performanc
e

Figure 4.3 Process Comparison: Stiffness and Safety
Based on the comparison done in tables 3.3, 3.4 and 3.5, graphs in figure 4.3 and
figure 4.4 has been derived. The graphs exhibit the comparative levels of performance
or trade offs between the six joining processes based on stiffness and safety (figure
4.4), and based on operation cost, flexibility and speed (figure 4.4) and the graphs are
purely prepared from my understanding of the literature and joining process and this
view about the processes can differ among organisations and individuals.
The figure 4.3 shows given safety criteria, RSW and MIG welding are comparatively
safer than SPR and FSW due to high forces involved in SPR and FSW operation and I
feel that laser welding and adhesives are less safer because their harmful effects and
thus require highly skilled labour and safety equipments.
RSW
Laser
MIG
SPR
Bonding
FSW
0
1
2
3
Rating
Joining process
Process Comparison Safety and Stiffness
Safety
Body stiffness
Safety 3 1 3 2 1 2
Body stiffness 2 3 2 2 3 3
RSW Laser MIG SPR
Bondi
ng
FSW
1- low
2- moderate
3- high

Figure 4.4 Process Comparison: Cost Flexibility, Automation and Speed
I consider RSW and MIG welding cheaper to operate compare to laser welding and
SPR because of high energy requirement by laser welding and high costs of the rivets
and even in terms of flexibility in operation adhesive bonding, RSW are more flexible
compared to other as adhesive bonding is applicable to all type of materials and RSW
can automated to high degree of freedom. FSW is growing processes but it looks
highly unlikely that it can achieve the flexibility and automation as in laser and other
welding processes. Laser welding could be one of the fastest joining processes and
also requires only single side for joining but need for proper alignment of parts and
problems in welding aluminium reduces its flexibility. Clearly RSW is one of the
established processes and meets most of the requirements and due this it has been
widely accepted in the automotive industry however, weight reduction strategies
demanding different joining processes has provided opportunities for other processes
and I feel a combination of self piercing riveting and laser welding could be promising
technologies for lightweight production of aluminium automotive bodies because of
RSW
Laser
MIG
SPR
Bonding
FSW
0
1
2
3
Rating
Joining Process
Process comparison
Operation Cost
Flexibility
Speed
Operation Cost 3 1 3 1 2 2
Flexibility 3 2 3 2 3 1
Speed 3 3 2 2 1 1
RSW Laser MIG SPR
Bondi
ng
FSW
1- poor
2- moderate
3- high

Technology management in automotive industry

Technology management in automotive industry

Technology management in automotive industry

Technology management in automotive industry

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