Post on 27-Dec-2021
Forum
Composite Technology
Supply chain for the manufacture of fibre-reinforced products
VDMA
Forum Composite Technology
Lyoner Straße 18
60528 Frankfurt am Main
Germany
Phone +49 69 6603-1932
Fax +49 69 6603-2932
E-Mail walter.begemann@vdma.org
Internet http://composites.vdma.org
Processing of thermosetting semi-finished products
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http://composites.vdma.orgwww.composite-arena.com
VDMA Forum Composite Technology
The Forum Composite Technology is made up of nine VDMA
associations bringing together machinery manufacturers’
skills in the conversion of fibre composites. As central contact
point for the industry, the forum is the interface to all firms,
associations and institutes involved in the manufacturing or
conversion process and the application of composites, offering
all partners a platform for cross-technology exchanges.
The Forum is chiefly concerned with
• Markets and customers: cooperation and exchange bet-
ween associations, clusters and other customer industry
organisations
• Exhibitions policy: as sponsor of the COMPOSITES
EUROPE trade fair, the Forum is establishing an important
trade fair hub in Germany
• Understanding the process: fostering innovative ability
based on a common understanding of the process along
the entire supply chain
• Research: networking of research and industry to pro-
mote pre-competitive research
• Public relations: joint articulation of interests and concer-
ted public relations activities
• Sourcing service: the Forum’s member companies present
their range of products and the services they offer in the
Composite Arena
Further flyer available on these topics:
• Resin transfer moulding (RTM)
• Thermoplastics compression moulding
Contact
Dr. Walter Begemann
VDMA Forum Composite Technology
Phone +49 69 6603-1932
E-Mail walter.begemann@vdma.org
Unlike thermoplastics, thermosetting fibre composites have a
chemically cross-linked molecular structure. These links mean
that thermosettings cannot be melted again, but they normally
have a higher mechanical strength and their breaking behaviour
is more brittle.
Typical applications include components for the electrical
industry, sanitation, rail and utility vehicles and increasingly
for aircraft and automotive industry. The thermoset matrix
makes these components suitable for both higher and lower
temperatures, unlike thermoplastics.
The basic principle of thermosettings manufacture is the sepa-
ration of the impregnation process in the making of composite
materials from the moulding process in the press or autoclave.
More recent developments seek to bring the two stages together
in order to reduce cycle time.
Combining thermosettings with carbon fibres offers better me-
chanical properties than using glass fibres, but is also markedly
more expensive.
Process characteristics:
• Complex three-dimensional components possible
• Limited storage time for semi-finished products at room
temperature
• Short cycle times
• Low shrinkage during manufacture
• Geometry limited by flowability of the semi-finished product
• Finishing (cutting, edge processing) required, but some may
be integrated into the press
• Sophisticated plant technology (moulding press, autoclave)
• Manufacturing may be automated
• High temperature stability
• Low elongation at rupture
• Good surface quality on both sides (depending on tool)
Classification of thermosetting semi-finished product processing
Reinforcement fibreThermosetCompositeAlternative processes for composite manufacture
1: Fibre manufacture2: Textile manufacture3: Manufacture of semi-
finished products4: Moulding5: Autoclave6: Finishing7: Testing, joining,
surface treatment8: Recycling
Raw material
Component
Final product
Raw component
Organic sheet
2
4
5
6
7
8
8
3
31
Placed material
Textilestructure
Cut Preform
Resin
SMC/BMC
FibrePrepreg
Fibre and textile manufacture Manufacture of semi-finished products Moulding Machine tools / precision tools Robotics, automation / mearsurement and testing
Alternatively, woven, non-crimp, warp-knitted, braided or knitted
fabrics are made for use in the resin matrix.
Relevant machine groupsMachines for the production and treatment of fibrg
• Machines for the production of carbon fibres
• Machines for the production of glass fibres
• Machines for the production of aramid fibres
• Drafting systems for filaments and tapes
• Cutting converters, stretch-breaking machines
• Preparatory machines for natural fibres
• Accessories
Machines for the production of textile structures
• Machines for the production of yarn
• Machines for the production of nonwovens
• Filament winding machines
• Braiding machines
• Fibre placement lines
• Flat knitting machines
• Warp knitting machines
• Multiaxial warp knitting machines
• Weaving machines
• Accessories
Relevant machine groupsMachines for the manufacture of composites
• Autoclaves
• Coating machines
• Extrusion lines / Extruder
• Laminating
• Peripherals
Relevant machine groupsMachines for composites processing/machining
• Tape laying machines
• Forming machines: High pressure presses for SMC/BMC
Precision tools for composites
• Dies and molds
Relevant machine groupsMachines for composites processing/machining
• Heating and cooling technology
• Forming machines
• Cutting and splitting machines
• Machines for surface treatment
• Drilling and milling machines
Precision tools for composites
• Cutting tools
• Clamping tools
Joining technology for composites
Relevant machine groupsHandling technology
• Robots
• Other handling equipment
• Equipment for linking and transport
Measurement and test systems
• Test systems for fibres, yarns, fabrics, on-line
• Test devices for fibres and filaments, off-line
• Test devices for staple fibre and filament yarns, off-line
• Test devices for composites and fabrics, off-line
• Gages and precision measuring equipment
• Measuring machines
• Machine vision and optical sensors
• Test devices for contaminant
The process chain for the manufacture of fibre-reinforced
thermosettings begins with the production of precursor
fibres from polyacrylonitrile (PAN). They are carbonised
as filament bundles (rovings) and directly cut for further
processing or else impregnated with the resin as endless
fibres in unidirectional, biaxial and multiaxial structures.
The next stage is to process the textile re-
inforcement structures into semi-finished
products. Fillers and dyestuffs are added to
the resin to obtain particular properties.
Sourcing service: www.composite-arena.com
Thermosetting semi-finished products are processed by hot press
moulding or else under pressure at high temperature in an autoclave.
The high temperatures create an irreversible cross-linking of the
material, which cannot be melted again.
The good flow behaviour of semi-finished products made from cut
fibres also means that highly complex geometries can be achieved.
Prepregs on the other hand allow significantly higher fibre contents.
For finishing with high-precision machine tools, a distinction is
made between the introduction of functional geometries and
fine surface finishing. For functional geometries, methods such as
drilling, milling or laser beam and water jet cutting are used, while
fine surface finishing is normally done by grinding and polishing.
The machining of fibre composites presents engi-
neers with completely new challenges for tool de-
velopment, since the familiar laws of metallurgy
cannot simply be transferred.
Unlike metallic materials, the properties of com-
posites are determined chiefly by the direction of
the fibres in the component. This means that fibre
composite materials cannot be machined equally
well in all directions.
If the composite consists of layers with the fibres
in different directions or composite layers are
combined with layers of metal, the machining
process is even more complex.
Robotics + automation covers the three
fields of robotics, integrated assembly
solutions (for assembly and handling) and
industrial image processing. These tech-
nologies are important building blocks
for the economic series manufacture of
filament-reinforced products. The positioning and alignment of
non-crimp fabrics, the handling of semi-finished products and the
robotised finishing of components are examples of how they can
be applied. Image processing provides reliable monitoring to ensure
that all important manufacturing parameters are maintained and
that quality is reproducible and assured.
Quality assurance is an essential aspect
of measurement and testing technology.
Quality assurance systems in the produc-
tion process have many advantages for
the user, such as lower production costs
resulting from the better utilisation of re-
sources. A high level of process reliability
means less waste and hence ultimately lower costs arising from
guarantee commitments and more satisfied end users.
Raw component
SMC (Sheet Moulding Compound) is made by impregnating cut fibres
with resin. This produces a sheet type semi-finished product.
In the case of BMC (Bulk Moulding Compound), cut fibres are added to
the resin to create an amorphous doughy mass which is further worked
by press moulding.
Prepregs are made from pre-impregnated endless fibres (unidirectional
fibres, non-crimp or woven fabrics, etc.) and are cured at high tem-
peratures and under pressure in an autoclave or by hot press moulding.
Large moulded parts (e.g. for aircraft manufacture) are processed in the
autoclave under vacuum since for them press moulding is uneconomic.
Resin
Textilestructure
Prepreg
Two part tool
Semi finished product
Negative form
Vacuum
Prepreg
Absorbent non-wovenVacuumfoil
Autoclave process
Moulding process
Raw marerial
Fibre
SMC/BMC
Placed material
Finalproduct
Component