189
7
5 Viscosity of the resin (η)—The viscosity of the resin needs to
be low so that resin is able to wet all filaments of roving and
tow passing through the resin bath. The high viscosity of
resin can adversely affect the processability of composites
using filament winding technology.
5 Residence time—The residence time of roving or tows is an
important processability parameter. In this process, the
residence time must be long enough so that all of the
filaments of roving and tows are wetted with resin.
5 Winding speed—The winding speed is an important
processing parameter that indirectly controls the residence
time of roving or tows in the resin bath. Low winding
speeds cause less fuzzing of carbon fibres; thus, an optimum
winding speed improves processability of the composite
using filament winding technology.
? Example 7.1 suggest the processing technology to be used for
the fabrication of (a) a high-pressure vessel, (b) frame of a
desert cooler, (c) a golf shaft, and (d) roof panels.
v Answer
(a) High-pressure vessel—A small-sized, high-pressure vessel
may be fabricated using a filament winding process, and a
large-sized, high-pressure vessel may be fabricated using a
tape layup process. Hoop winding would be needed in
combination with helical winding based on the design
requirements for the high-pressure vessel.
(b) Frame of desert cooler—This may be fabricated using a hand
layup process with a wooden mould.
(c) Golf shaft—This may be fabricated using a filament winding
process. In this process, predominantly helical winding will
be carried out.
(d) Roof panels—These may be fabricated using a hand layup
process with either wooden or plaster of paris moulds or
patterns.
7.1.4 Polar Winding Technology
In polar winding technology, the winding takes place in a circular
path (i.e. pole to pole). This allows both geodesic and non-geodesic
filament winding. In this process, the mandrel is supported by one
end, which facilitates the long helical winding from pole to pole.
The fabrication of a polar wound composite product is shown in
. Fig. 7.6.
The fibre delivery system (payout eye) in this technology can be
moveable or stationary. In a stationary system, mandrel rotates end to
end in addition to rotating on its polar axis. A movable delivery system
rotates around the mandrel in a polar orbit, and the mandrel rotation
is confined to incremental rotation. Polar winding technology provides the possibilities for non-geodesic path winding with specially
designed mandrels. Care must be taken for the sagging of the mandrel
7.1 · Open Mould Processing Technologies
7
5 Viscosity of the resin (η)—The viscosity of the resin needs to
be low so that resin is able to wet all filaments of roving and
tow passing through the resin bath. The high viscosity of
resin can adversely affect the processability of composites
using filament winding technology.
5 Residence time—The residence time of roving or tows is an
important processability parameter. In this process, the
residence time must be long enough so that all of the
filaments of roving and tows are wetted with resin.
5 Winding speed—The winding speed is an important
processing parameter that indirectly controls the residence
time of roving or tows in the resin bath. Low winding
speeds cause less fuzzing of carbon fibres; thus, an optimum
winding speed improves processability of the composite
using filament winding technology.
? Example 7.1 suggest the processing technology to be used for
the fabrication of (a) a high-pressure vessel, (b) frame of a
desert cooler, (c) a golf shaft, and (d) roof panels.
v Answer
(a) High-pressure vessel—A small-sized, high-pressure vessel
may be fabricated using a filament winding process, and a
large-sized, high-pressure vessel may be fabricated using a
tape layup process. Hoop winding would be needed in
combination with helical winding based on the design
requirements for the high-pressure vessel.
(b) Frame of desert cooler—This may be fabricated using a hand
layup process with a wooden mould.
(c) Golf shaft—This may be fabricated using a filament winding
process. In this process, predominantly helical winding will
be carried out.
(d) Roof panels—These may be fabricated using a hand layup
process with either wooden or plaster of paris moulds or
patterns.
7.1.4 Polar Winding Technology
In polar winding technology, the winding takes place in a circular
path (i.e. pole to pole). This allows both geodesic and non-geodesic
filament winding. In this process, the mandrel is supported by one
end, which facilitates the long helical winding from pole to pole.
The fabrication of a polar wound composite product is shown in
. Fig. 7.6.
The fibre delivery system (payout eye) in this technology can be
moveable or stationary. In a stationary system, mandrel rotates end to
end in addition to rotating on its polar axis. A movable delivery system
rotates around the mandrel in a polar orbit, and the mandrel rotation
is confined to incremental rotation. Polar winding technology provides the possibilities for non-geodesic path winding with specially
designed mandrels. Care must be taken for the sagging of the mandrel
7.1 · Open Mould Processing Technologies