1. FW: filament winding AFP: automated fibre placement ATL: tape laying pultrusion tube rolling
John Summerscales

2. Filament winding
continuous fibre reinforcements are precisely positioned in a pre-determined pattern on a rotating mandrel (mould tool for filament winding)
normally computer numerically controlled (CNC) to permit highly automated production of axisymmetric components

3. Filament winding simple machine: just two axes
rotation of the mandrel
translation of the feed eye on an axis parallel to the machine axis
complexity characterised by the number of degrees of freedom:
up to six separately controlled axes
usually three orthogonal and three rotational axes

4. Filament winding
image from

5. Filament winding - tension
fibre tension is critical to the operation of a filament winding machine
normal to have fibre tensioners (closed-loop controlled servo-driven "dancers")
tension required depends on
type of fibre
part diameter
winding pattern

6. Filament winding - tension
fibre tension directly affects
fibre volume fraction
void content
and, in turn, influences the strength and stiffness of the composite part.
difficult to maintain tension on flat surfaces
axial winding not a preferred orientation on cylinders.

7. Filament winding - impregnation
resin impregnation
image from

8. Filament winding - winding patterns
hoop (90º) a.k.a girth or circumferential winding
angle is normally just below 90° degrees
each complete rotation of the mandrel shifts the fibre band to lie alongside the previous band.
helical
complete fibre coverage without the band having to lie adjacent to that previously laid.
polar
domed ends or spherical components
fibres constrained by bosses on each pole of the component.
axial (0º)
beware: difficult to maintain fibre tension

9. Filament winding - winding patterns
hoop : helical:
polar:
images from:

10. Filament winding - winding pattern
Kevlar component
image from

11. Filament winding - geodesic path
simplest fibre orientation is the geodesic path
assumes non-slip winding
once winding has commenced, fixed fibre path at any point dictated by the Clairaut angle ( r.sin a = constant)
where r is local radius, a is local angle
at bosses, a = arcsin (rb/r)
where rb = angle at the boss (polar opening)
exploiting friction, it is possible to achieve non-geodesic winding within limits.

12. Lattice structures (anisogrid)
can be produced by partial coverage and careful choice of relative band positions
image from Vasiliev et al, Composite Structures, 2001, 54(2-3).
GeoformTM communication masts, railway gantries, spray booms, etc

13. Filament winding - applications
pressure vessels, storage tanks and pipes
rocket motors, launch tubes
Light Anti-armour Weapon (LAW)
Hunting Engineering made a nesting pair in 4 minutes with ~20 mandrels circulated through the machine and a continuous curing oven.
drive shafts
Entec “the world’s largest five-axis filament winding machine” for wind turbine blades
length 45.7 m, diameter 8.2 m, weight > 36 tonnes.

14. AFP: automated fibre placement
multi-axis robot wet-winds fibre around a series of pins (or similar restraints within a mould) in a predetermined pattern.
not limited by geodesic paths
used to produce Geoform (lattice-work with coverage in specific bands)
better for thermoplastic matrix composites
on-line consolidation and cooling permit use without the requirement for the fibre restraints.

15. ATL: automated tape laying
computer-numerically controlled (CNC) technique laying prepreg reinforcement tape
Cartesian framework for gross positioning (rather than a primarily rotational axis robot)
rotational freedoms close to the work-piece.
used for thermoset or thermoplastic matrix
limited to flat or low curvature surfaces
high quality aerospace composites e.g. flight control surfaces and wing skins.

16. Pultrusion continuous constant cross-section profile
normally thermoset (thermoplastic possible)
impregnate with resin
pull through a heated die
resin shrinkage reduces friction in the die
polyester easier to process than epoxy
tension control as in filament winding
post-die, profile air-cooled before gripped
hand-over-hand hydraulic clamps
conveyor belt/caterpillar track systems.
moving cut-off machine ("flying cutter")

17. Pultrusion production of constant cross-section profiles
Image from (no longer online)
Videos: Soc.Mfg.Eng (1’18”) Strongwell (1’32)

18. Pultrusion - design manuals by Quinn and Hartley
seek uniform thickness in order to achieve uniform cooling and hence minimise residual stress.
hollow profiles require a cantilevered mandrel to enter the die from the fibre-feed end.

19. Pultrusion -applications
panels – beams – gratings – ladders
tool handles - ski poles – kites
electrical insulators and enclosures
light poles - hand rails – roll-up doors
450 km of cable trays in the Channel Tunnel
plus ...

20. Pultrusion (ACCS/Composolite®)
Advanced Composite Construction System
components: plank and connectors
used in Aberfeldy and Bonds Mill Lock bridges
Images from and.. (no longer online)

21. Pultrusion - variations of process
pulwinding/pulbraiding: fibres are wound onto the core of the pultrusion before it enters the heated die.
pulforming: the profile is subjected to post-die shaping.

22. Tube rolling (mandrel wrapping)
a technique where pre-preg is formed onto a tapered mandrel and consolidated using shrink-wrap.
most often used to make fishing rod blanks