|Materials Research Projects at
Hitchin/MERL aims to be active in new and emerging technologies by
knowledge, know-how and data for industrial exploitation. Element
a multi-disciplinary approach combining expertise in chemistry, physics
and engineering. Approximately two thirds of staff have degrees or
higher degrees. Research is funded in several ways.
Click on the titles below to see recent and ongoing materials
research work at Element
Commission part funded projects
MERL has extensive experience of projects funded by the European Commission
and participated in project consortia under the fourth (FP4), fifth (FP5) and
sixth (FP6) framework programmes. In addition MERL is participating in various
Technology Platforms for the formation of the seventh programme. Under FP5,
MERL was co-ordinator and technical lead in three RTD projects and Work Package
leaders in two Thematic Networks. Under FP6 MERL is active in several projects
as partners in the transport sector, materials sector and aerospace sector
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see current project involvement. MERL is open to approaches from other organisations
for partnering opportunities. For more information contact Dr
MERL conducts a range of UK government funded projects either as the project
lead or as a partner or subcontractor. Typically projects are funded via the
Technology Strategy Board (TSB), The Department for Innovation, Universities
and Skills' Grant for Research and Development, and the Waste and Resources
Action Programme (WRAP). For further information on funding opportunites contact Dr
projects or joint industry project (JIP)
Consortium projects are fully funded by a group of organisations on a cost
sharing basis. Projects usually have a strong industrial focus and international
participation. Typically projects are 2 - 3 years duration and in some cases
are continued into a second phase. Participants in consortium projects monitor
and guide the work programmes via a project steering committee. Benefits of
participation include cost effectiveness and direct influence on the work programme.
MERL is proactive in developing new projects; if you have a particular research
need that you would like to discuss contact Dr
MERL funds internal research to develop new know-how and technology for exploitation.
Examples include low temperature cure (LTC) rubber which has US and EU patents,
impact protective coatings for composites and ED resistant materials. MERL
also works with Universities on student projects at undergraduate and post
graduate level. For further information please contact Dr
carbon and glass fibre reinforced thermoplastics will play an important
role in being able to meet the ambitious energy saving and reduced
CO2 emissions targets for future aircraft and vehicles. Since adhesive
of most thermoplastics cannot be performed without extensive surface
preparation, mechanical fastening is usually the
obvious choice when using traditional joining techniques. However,
a number of
new joining techniques like ultrasonic, resistance or induction
welding have been investigated formanufacturing reliable high performance
components. Laser transmission welding is a technique with great potential
reinforced or un-reinforced thermoplastic components, offering the
possibility of a flexible, controllable and contact free process with
is coordinating the LaWocs EUROSTARS funded project. A
project consortium has been assembled comprising five
operating within the field of thermoplastic
composites and working on the manufacturing of TPC base materials for
specific applications, injection moulding, forming of TPC components,
induction welding and testing of composites.The SMEs are supported by
one large company, representing the global market leader in manufacturing
of TPC materials as well as two non-university research institutes, specialized
within the fields of fibre technology and laser technology. The other
project partners are:
Continuous carbon and glass fibre reinforced composite materials (CFRP,
GFRP) are recognized as having significant weight saving potential
and are therefore important materials for many applications. There
are clear examples in the field of mobility including aerospace,
automotive, marine and rail sectors. However the need for components
based on fibre
reinforced composites is particularly increasing within the field
of energy, e.g. wind and tidal turbines, heavy-duty pipelines for
applications and electronics, as well as within the field of sports
In particular CFRP is characterized by high stiffness and strength, excellent
corrosion resistance as well as good resistance to static and dynamic loads.
An outstanding property of CFRP is the potential of significant weight
reduction compared to metallic materials, e.g. up to 30% for aluminium.
Thus CFRP is an important material to contribute significantly to energy
and CO2 savings by use in advanced light weight structures.
Although thermoset polymers mainly based on epoxy resins are the predominant
matrix material, reinforced composites based on thermoplastic polymer matrices
(TPC) are of increasing interest due to their superior formability and
recyclability as well as the added benefit of material consolidation in
just one process step. Thermoplastics offer several other benefits such
as uncritical and unlimited storage times, a better impact tolerance compared
to thermoset matrices, a good ultimate strain performance, reduced crack
propagation, excellent chemical resistance and rapid forming processes.
Another significant advantage over thermoset based composites is their
A current barrier for the comprehensive use of TPC structures is the lack
of economic, quick and reliable component manufacturing processes. To overcome
this deficit, fully-automated process chains for the manufacturing and
assembly of thermoplastic composites have to be developed in order to achieve
production rates and cycle times required by automotive and aircraft industry
as well as the civil engineering sector. Integrated process cells can be
adapted to specific material requirements and to new process elements including
laser based techniques for cutting and in particular joining applications.
Different techniques like resistance welding, ultrasonic welding, vibration
welding or induction welding are used, revealing respective advantages
It is the aim of the LaWocs project to develop a novel joining technique
for TPC parts based on the laser transmission welding technology (LTW).
Currently LTW is an industrially established welding technique for unreinforced
and partially reinforced thermoplastics offering the possibility of flexible,
controllable and contact-free processing with a high automation potential.Within
the framework of the project this technology will be transferred to the
specific requirements of TPC materials. Besides the manufacturing
of pure TPC components, combinations of reinforced and unreinforced or
partially reinforced materials will be evaluated.
In order to achieve these goals, a project working plan has been arranged
consisting of the following main activities:
- Development of adapted TPC base materials and manufacturing of real components
- Development of laser welding process for TPC materials and welding of
- Testing of novel TPC structures and real parts according to industrial
- Exploitation of project results.
Besides the aerospace sector, the products and services of the SMEs are
established on other markets including wind and tidal turbines, Oil and
Gas pipelines and electronics. The availability of this new welding technique
will represent a unique feature, which will strengthen the position of
the SMEs and open new markets for these materials and manufacturing technologies.
Laser transmission welding of thermoplastics
is increasingly gaining importance as an alternative welding process compared
techniques, such as heated tool welding, friction welding or ultrasonic
advantages of a laser based welding
are the high flexibility of the process, the low mechanical load, the
geometries as well as the precise energy deposition within the process
zone and the attainability of high welding velocities.
The main advantage
of laser transmission welding in comparison to other welding processes
is the precise and controllable energy deposition, which allows for localizing
the melting zone to a small region around the contact zone of the plastic
parts in combination with a high optical quality of the weld seam. Tensile
strengths of the value of the base material can be achieved.
Usually, both joining partners
are of the same base material, but different polymers which have similar
melting points and sufficient chemical compatibility may be welded as well
(e.g. the combination PMMA to ABS) and the La Wocs project is seeking to
develop the methods for joining such materials. The NIR absorption by the
lower partner is generated by means of adequate colorant technologies,
in the simplest case the addition of carbon black. Currently, additives
are available which yield plastic parts that are colored or black for the
human eye, but transparent for the laser radiation. On the other hand,
there are additives white or colored for the human eye, but absorbing for
the laser radiation. Thus, even black-to-black or white-to-white combinations
can be realized using polymers with absorption characteristics specifically
adapted to the laser process.
Figure 1: Principles of laser transmission welding
Four variants of laser transmission welding are used:
• mask welding.
In contour welding, the laser beam is guided along the joining contour. With
this technique, either the laser beam or the materials to be joined have to be
moved. With the use of robots it is possible to generate two-dimensional and
three-dimensional contours. With contour welding, very stringent tolerance requirements
for the surface and planarity of the parts to be welded have to be set. One important
factor determining the success of the process is the bridging of gaps.
In simultaneous welding, diode lasers in a welding head are arranged individually
in such a way that they fit to the joining contour. Both materials to be joined
are exposed simultaneously so that they melt and are welded to each other. No
relative movement between laser beam and the parts to be welded is necessary.
A relatively new variant of the simultaneous welding process, presented by Leister
Process Technologies, Sarnen/Switzerland, is the so-called radial welding used
to join cylindrical components. Here, a mirror deflects a circular laser beam
in such way that the outer symmetrical surface of the cylindrical component is
irradiated radially to generate a circumferential weld seam.
In quasi-simultaneous welding the laser beam is repeatedly guided along the joining
contour by scanning mirrors with very high feed rates (up to 10 m/s). Due to
the high speed, the whole joining area is heated and plasticized almost simultaneously.
This method is very flexible, but slower than the simultaneous method.
When mask welding is used, a mask is placed between the laser source and the
parts to be welded. The laser beam with linear profile is guided across the mask
so that only those areas are welded where the mask is left open. With this method,
very fine welding seams with a width of less than 100 µm can be realized.
Investigations have shown that one polymer type behaves differently regarding
laser weldability depending on the producer, even if the colouring is comparable
and a constant thickness is used. Possible reasons for varying optical material
properties are different parameters used during the production process of the
material, the varying content of other filling materials and differences in size
and distribution of the particles of added colouring agents, as well as different
modifications of the original granulated material used for the injection moulding
of the samples. The granulated material can be coloured on delivery by adding
colour pigments, or the colour pigments are added to the natural material when
injection-moulded. Due to this wide spectrum of materials, selection of polymer
types, suitable for a specific welding process, and collection of relevant data
for successful process implementation is challenging.
Therefore, the determination of main factors influencing the weldability of different
thermoplastic materials (absorbing and transparent), taking into account properties
like colour and filling content, has become a focus of interest. An initial step
in the process to determine the weldability of materials is to characterize the
optical properties of partially transparent materials and to perform transmittance
measurements at different wavelengths in the near infrared spectral range.
Practical welding experiments showed that not all laser-transparent samples are
suited for laser beam welding. Thus, conventionally measured transmittance values
do not provide enough information about the weldability, since they do not contain
any details about thermal characteristics or about losses due to reflection at
the polymer surface. Furthermore, the determination of transmittance values is
difficult in the case of semi-crystalline or filled polymers due to their light
scattering ability which is dependent on the degree of crystallization or the
filler content as well as the size and shape of the crystallites or the filler
particles. Due to limitations of the instrumentation, conventionally measured
transmittance values are often too small.
Therefore, a thermographic system for an easy to handle, fast and non-destructive
evaluation of thermal and optical properties of materials regarding laser beam
weldability was developed.
Expected Project Results
The results expected at the end of the project can be divided into two
main categories. Firstly, new materials will be available, which are
specifically designed to the requirements for LTW as well as for the
required mechanical properties. Secondly, a joining process will be
available, providing all necessary process knowledge regarding the
laser transmission welding of different TPC material combinations.
The project includes the development of adapted, hybrid/graded structures
including the complete process knowledge with respect to fibre and matrix
handling and the integration of dissimilar reinforcements. Besides the
applicability of LTW, this knowledge will be useful also for the fabrication
of additional structures with the objective of manufacturing light-weight
At the end of the project, the novel joining technology will be demonstrated
by preparation of a laser transmission welding process suitable for the
fabrication of at least 3 pilot parts, arising from the fields of supports
and retainers, structural elements based on high-performance polymers
as well as endless-fibre reinforced composites based on lower graded
It is expected that for at least one of the investigated pilot parts,
a minimum weight reduction of 30% compared to mechanical joining techniques
will be realized. The corresponding processing time shall be reduced
The project results will be useful for the end-users, such as the aerospace
manufacturers, automotive OEMs, marine and rail companies. The “real” drivers
of innovation in these areas, however, are usually their suppliers. Therefore,
the companies within the project – many of which are already suppliers
to these end users – will use the methods and materials developed
within the project to produce innovative and light-weight components
as a demonstration of the advantages of these technologies.
New markets and the respective end users will be approached by the SME
partners, such as electronics/computers (housings, screenings), car/railway/yacht
interiors, furniture industry (design elements, covers, functional elements),
white goods/household appliances (design elements, stiffeners). This
will be facilitated by the high throughput of these fast, flexible and
automated production processes which enables this technology to be applied
to lower cost markets.
Engineering Research Laboratory Ltd (MERL) provides
R&D, mechanical and chemical testing, finite element services & general
consultancy services on polymer materials for engineering systems & structures
and are recognized internationally as one of the foremost experts
in evaluation of durability of composites in the oil & gas industry
and aerospace industry. MERL has a client base of several thousand
industrial companies worldwide covering all industry sectors and
provides testing solutions from concept/feasibility and materials
selection to disposal and re-use.
||Kok & Van
Engelen Composite Structures BV (KVE) has evolved
to a full service engineering partner in composites, system design
and research and technology development. KVE has contributed significantly
in making composites available not only in the domain of aerospace,
but also for more down to earth applications. Optimal product design
and engineering, R&D for efficient manufacturing technologies
and systems engineering with integrated composite parts are keywords
in the services delivered. The major markets are aerospace, medical,
civil, automotive, and machine construction.
Composite Solutions Ltd (EPL) specializes in the
design, development and commercialization of advanced polymer composite
solutions. Spanning the complete development cycle from applied research
through product design, process development, material testing and
certification, to setting up manufacturing plant, EPL work with OEMs
and end-users to develop and demonstrate composite solutions that
provide clear technical, economic and environmental benefits over
existing structures. EPL will help develop the manufacturing and
process conditions to fully evaluate and commercialise the laser
Aerospace Ltd (TODS) is an AS9100 accredited company
that specialises in the design, development and manufacture of Aerospace
composite components, structures and assemblies. The company’s
main customers include – Augusta Westland, Airbus, GKN Aerospace,
BE Aerospace and Contour Premium Aircraft Seating. Tods have extensive
engineering capability, the main CAD Design tools are CATIA V4 and
V5, Solid Works is also used; FE Analysis is performed using NASTRAN/PATRAN.
The company has an excellent record for developing production methods,
designing components and manufacturing using – glass, carbon,
and Kevlar fibres – thermoplastic and thermoset matrix and
novel honeycomb materials.
Kunststoff-Technik GmbH (DEVA) works in the field
of plastics processing and tool manufacture with high competence,
productivity and reliability, providing continuous innovation and
most up-to-date technologies. Products made from conventional (PA6.6,
PC, PP, etc) as well as high-temperature plastics (PEEK, Teflon,
etc) are manufactured, using mainly injection molding technology.
Consequently, DEVA has customers in medical technology, electrical,
sanitary engineering and office furniture industries, as well as
navigation, white goods and especially aerospace industry.
CATE ADVANCED COMPOSITES BV (TENCATE) as a Dutch
global operating company is a leader in growing market niches for
specialist, functional materials, which primarily relate to the areas
of safety and protection and improvement of the performance of the
material in the broad sense. TenCate Advanced Composites is a leading
supplier of thermoplastic and thermoset solutions for the Aerospace
and Industrial industry. The thermoplastic prepregs are known in
the industry under the Cetex brand and are found in commercial and
military aircraft ranging from structural to interior applications.
TenCate provides both thermoplastic prepregs in unitape or fabric
form in a variety of high end thermoplastics including PEEK, PEKK,
PPS, PEI and Nylon 11.
Zentrum Hannover e. V. (LZH) supports applied research
in laser technology on a non-profit basis. LZH is involved in national
and international R&D projects in the field of laser development
and laser applications, technical and scientific consulting to link
research and practice, and industry-oriented training of experts
for applying and operating laser systems. The close cooperation between
production engineers, material scientists, and physicist allows for
finding interdisciplinary solutions in all fields of laser applications.
Bremen e.V. (FIBRE) has numerous competences in modeling,
manufacturing, processing and testing of single fibers, fiber bundles
and textile products as well as in reinforced plastics with carbon,
glass or natural fibers in thermoplastic and thermoset matrices.
Research work is based on modern laboratories, e.g. equipped with
mechanical testing machines for static and dynamic load under variable
conditions (temperature, humidity etc). FIBRE is member of the “CFK-Valley” Stade.
Element Hitchin. The registered company address of:
Element Materials Technology Hitchin Limited is 5 Fleet Place, London EC4M 7RD,
Registered in England. Company registration number: 08149114.
Polymer Engineering, Testing, Inspection, Research and Development, UK