This paper illustrates the importance of adopting the Laser Beam Welding (LBW) process in aircraft manufacturing which will enable the manufacture of aircrafts of reduced weight. The use of this technology leads to a much higher degree of cost savings in the aircraft industry.

1. Leverage modern technology to
build fuel efficient aircrafts

2. Table of Contents
Abstract
Existing Problems
Laser Beam Welding (LBW) – An Introduction
Advantages of Laser Beam Welding
Market Trends
Best Practices
CCoommmmoonn IIssssuueess
Conclusion
References
Author Information
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3. Leverage modern technology to build fuel efficient aircrafts | 3
Fuel efficiency in modern aircrafts has become a major challenge because of the huge costs involved in
fuel consumption. A key reason to the present level of high fuel consumption is the weight of the aircraft,
which is directly proportional to the amount of fuel consumed.The industry today is faced with the
challenge of reducing the weight of the aircraft thereby reducing overall costs. Aircraft weight can be
reduced by employing the Laser Beam Welding (LBW) process, which simplifies and integrates tthhee mmeettaall
fuselage structure. This process has been hailed as a pioneering technology with great potential. It offers
the possibility of making joints from some of the lightest metals and their combinations. This, in turn,
leads to the efficient manufacturing of low weight metal fuselage structures.
Awareness about laser beam welding is still nonexistent, even though there has been a considerable
amount of discussion about the technology. Hence, there is a need to drive wider and more effective
usage of LBW. One way to do this is by emphasizing on detailed knowledge about the LBW process in the
aircraft industry. This will exponentially increase the benefits offered by this technology.
This whitepaper illustrates the importance of adopting the LBW process in aircraft manufacturing
which will enable the manufacture of aircrafts of reduced weight. This will lead to a much higher degree
of cost savings in the aircraft industry.
Aircraft fuselages consist of various intricate parts, all joined together with precision. Currently, riveting is
a popular way of fastening two parts of metal together. Be it simple parts or precision based complex
parts, this conventional method joins them using millions of rivets. Riveting may be considered an
advanced automated technology. However, further development in this technology now looks very
unlikely.
Riveting won’t yield a remarkable increase in productivity or significant weight savings even after the
structural parts of an aircraft are re-designed to reduce the number of rivets. Due to this reason, aircraft
manufacturers have been exploring new technologies that could replace riveting. The overwhelming
consensus across the industry is that LBW is presently the only cost-efficient option for joining large metal
fuselage parts with stringers and other aero-structural parts.
LBW is a fusion welding technique that is used to join multiple pieces of metal through the use of a laser
beam. This laser beam provides a concentrated low heat source, allowing for narrow, deep welds and
high density welding rates. This technology enables 3-D laser welding of stringers on extremely large and
complex fuselage structures. It is an eco-friendly and green technology that adds value for the aircraft
manufacturer by increasing productivity and reducing the aircraft’s total weight by as much as 15%.
© 2014, HCL Technologies. Reproduction Prohibited. This document is protected under Copyright by the Author, all rights reserved.
Abstract
Existing Problems
Laser Beam Welding (LBW) – An Introduction

4. Leverage modern technology to build fuel efficient aircrafts | 4
Fig 1. Potential weight reduction for LBW
Advantages of Laser Beam Welding
These are some of the benefits offered by LBW over conventional riveting methods:
Riveting speed is 0.15 m/min to 0.25 m/min while the speed of LBW is 8 m/min to 10 m/min. LBW
still pays off by way of lower inspection time. The tooling for the LBW process is very simple and
flexible.
The wide rivet straps in the aircraft skin and at the butt ends of the stringer are no longer required.
It also eliminates the need for a filler metal between the riveted parts. This reduces the structure’s
weight by 5% straightaway.
The welded joint displays greater compressive and shear strength despite its lighter weight.
Not only is the cost of production lower, but the structure is less susceptible to corrosion. While
manufacturing aircrafts, even a single kilogram of weight is worth saving, and these savings brought
about by LBW do add up considerably.
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5. Leverage modern technology to build fuel efficient aircrafts | 5
Weight saving
Corrosion resistance
Fixture
Operation cost
Heat-affected zone
Distortion
PPrroodduuccttiioonn rraattee
Automate process
Capital cost
LBW
Better
Better
Better
Average
Better
Better
BBeetttteerr
Better
Riveting
“Z” type stringer “L” type stringer
Skin
Riveting Riveting Skin
1. Competitive analysis
The impact of globalization, evolving markets, and the development of technology has resulted in intense
competition amongst most aircraft OEMs. Aircraft weight reduction has been the main concern for
manufacturers, to be profitable in their ventures.
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Market Trends
Table 1: Comparison between Riveting and Laser Beam Welding
Fig2. Potential weight reduction for LBW
Average
NA
NA
Better

6. Leverage modern technology to build fuel efficient aircrafts | 6
The strategy to address these concerns can be accomplished by
Development of new materials
New manufacturing methods
Advanced processes
New design implementation
The use of composites has increased in aircraft manufacturing, amounting to 50%-53% of the structure
mass for the Boeing B787 and Airbus A350/A380. However, light metals still account for over 30% of the
structural mass. The development of third generation metal alloys substantiates the fact that light metals
have great potential for use in aircraft manufacturing.
The benefits of LBW in aircraft manufacturing justify the need for increased knowledge about this
technology in the industry. Conventional aircraft structure building methods need to be discarded and
replaced with joints which use light metals and their combinations. Metal compositions in popular
aircrafts are listed in Table 2.
Table 2. Metal composition in popular aircrafts
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A320
A350 XWB
A380
B777
B787
Composite Aluminium Titanium Steel Other
15%
53%
25%
11%
50%
65%
19%
61%
70%
20%
06%
14%
10%
07%
15%
11%
06%
10%
11%
10%
03%
08%
04%
01%
05%
2. Investment scenario
Current market analysis shows that the demand for air travel continues to increase steadily. Aircraft
OEMs and airline companies are making expansions and investments to promote the XXL generation
aircrafts. These new aircrafts can easily carry more than 500 passengers for 12,000 to 1155,,000000 kkiilloommeetteerrss..
However, these aircrafts will take more payload than regular twin decks, which can be justified by the
reduction in the amount of air traffic in the future. They will also set new standards for environmental
protection and fuel consumption. Inspite of having a gigantic construction, there will be a focus on lesser
fuel consumption resulting in the release of fewer pollutants into the atmosphere, thereby benefiting the
environment. The volume of fuel consumption can be lessened by making the aircraft lighter. Lighter
aaiirrccrraaffttss ccaann bbee bbuuiilltt bbyy aaddooppttiinngg LLBBWW tteecchhnniiqquueess aanndd rreeppllaacciinngg tthhee rriivveettiinngg pprroocceessss..
Gigantic passenger airliners of the XXL generation raise huge risks and challenges for aircraft
manufacturers. This is to justify the endeavor to make production and operating costs for high-flyers,
economic and reasonable. Hence high-precision joining technologies such as LBW are being implemented
for fuselage sections, thereby reducing aircraft weight by up to 15%.

7. Leverage modern technology to build fuel efficient aircrafts | 7
Here are a couple of industry practices that can act as success enablers for LBW.
Manufacturers may employ various aluminum composite techniques, modifying or redesigning the
existing aircraft structural parts for best effect
Redesign to reduce/minimize rivet counts
Eliminate fasteners by substitutes/alternatives
Use alternate fastening methods
Introduction/use light density material having more strength and stiffness
Apply different methods to manufacture structural parts, implement new designs, economic designs
at initial stages
Considering these industry best practices, LBW is the most ideal high-end technology for designing
aircrafts in the aviation industry.
1. Complexity in the process
LBW is a high speed process which enables a reduced fuselage weight and cost savings for the aircraft
industry. Yet, the numerous variables such as joint types, structures, process, design parameters and
fixtures make it a complex process. The selection of joint types, structures and material determines the
amount of weight reduction. The selection of processes, parameters and fixture design determines the
possible welding results and defects. Any mistake or miscalculation made during this selection process
will result in limitations and hence serious problems to the entire welding procedure.
2. Metallurgical challenges
LBW, like other fusion methods, is subject to common metallurgical problems such as hot cracking and
porosities. In order to ensure stability under extreme conditions typical with aircraft operations, welding
defects need to be controlled substantially. Porosities are intrinsically related to the weld, occurring due
to a large number of factors such as - alloy composition, surface contaminants, improper gas shielding,
and keyhole collapse and hydrogen release.
Fig 3. Porosites
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Best Practices
Common Issues

8. Leverage modern technology to build fuel efficient aircrafts | 8
Conclusion
The aircraft manufacturing industry is undergoing many changes due to new material development,
advanced technology, and improved design principles. A significant change has arisen through the use of
concurrent engineering, a technology which has resulted in better product development cycles.
The LBW process allows for not only weight reduction but also for the development of optimized panels,
thereby decreasing manufacturing lead time. Even with inspections and process control, it is still profitable.
Furthermore, the structure becomes less susceptible to corrosion since holes in the skin are avoided and
gaps in the butt joints are eliminated. It also eliminates the need for a filler metal between riveted parts. This
reduces the structure’s weight by a remarkable 5%.
This eco-friendly and green technology is considered a significant value-add for aircraft manufacturers. It
helps them to save up to 20% of the aircraft’s total weight. This leads to a massive reduction in fuel
consumption and will release fewer pollutants into the atmosphere, thereby protecting the environment.
References
1. Fraunhofer Institute for Material and Beam Technology IWS | www.iws.fraunhofer.de
2. Airbus Deutschland GmbH | www.airbus.com
3. EADS | www.eads.com
4. The Boeing Company | www.boeing.com
Author Information
Raghavendra Baikerikar
HCL Engineering and R&D Services (ERS) Group
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