225
8
alone will not be able to bring down the manufacturing costs until
nonrecurring costs and DOC are also brought down. Thus, a lifecycle cost analysis should be conducted along with the traditional
trade-off between the overall properties of composites and their
cost. Current developments in the area of advanced moulding processes of composites are given here.
8.3.1 Stitched Preform Followed by VARTM
This process involves the stitching of reinforcement fabric on the mould
for snug fitting followed by VARTM to fabricate the composite part.
Small- to medium-sized stitched preform-based composite products
are in use in composite industries. This method is not cost-effective for
small- to medium-sized thin parts; to take full advantage of this
method, the parts must be thick and large. For the acceptable use of
this technology for big products, an appropriate automatic stitching
machine is needed because the preforms are of different shapes and
thicknesses. The stitching of preforms of various skin thicknesses—
ranging from less than ¼ inch to more than 1 inch—is required.
8.3.2 Continuous Sandwich Panel
Continuous sandwich panels may be obtained in thermoplastic and
thermosetting composites. The thermosetting composite panels
may be produced through a pultrusion process, whereas thermoplastic sandwich panels may be manufactured through an extrusion
process. However, these processes are limited to making flat, constant sandwich panels. Floor panels, door panels, partitions, etc. are
the major products from flat sandwich panels. Continuous sandwich panels of complex shapes and variable thickness are produced
in abundance for such applications.
8.3.3 3-D Weaving
3-D weaving of reinforcing yarn is a machine-dependent operation.
The cost of 3-D weaving is prohibitively high due to the weaving
machine cost. The composite product made from 3-D preform is
similar to an isotrophic material having good mechanical properties in all three directions.
8.3.4 Mechatronics
Composite parts for high-end applications (aircrafts, missiles, etc.)
in general are made in batches, so production rates are usually low.
Mechatronics is a semiautomated process for the design and fabrication of any product. As a result, this process may be used for the
manufacturing of composite products for high-end application. The
mechatronics process ensures high-quality products.
8.3 · Future Composite Manufacturing Technologies
8
alone will not be able to bring down the manufacturing costs until
nonrecurring costs and DOC are also brought down. Thus, a lifecycle cost analysis should be conducted along with the traditional
trade-off between the overall properties of composites and their
cost. Current developments in the area of advanced moulding processes of composites are given here.
8.3.1 Stitched Preform Followed by VARTM
This process involves the stitching of reinforcement fabric on the mould
for snug fitting followed by VARTM to fabricate the composite part.
Small- to medium-sized stitched preform-based composite products
are in use in composite industries. This method is not cost-effective for
small- to medium-sized thin parts; to take full advantage of this
method, the parts must be thick and large. For the acceptable use of
this technology for big products, an appropriate automatic stitching
machine is needed because the preforms are of different shapes and
thicknesses. The stitching of preforms of various skin thicknesses—
ranging from less than ¼ inch to more than 1 inch—is required.
8.3.2 Continuous Sandwich Panel
Continuous sandwich panels may be obtained in thermoplastic and
thermosetting composites. The thermosetting composite panels
may be produced through a pultrusion process, whereas thermoplastic sandwich panels may be manufactured through an extrusion
process. However, these processes are limited to making flat, constant sandwich panels. Floor panels, door panels, partitions, etc. are
the major products from flat sandwich panels. Continuous sandwich panels of complex shapes and variable thickness are produced
in abundance for such applications.
8.3.3 3-D Weaving
3-D weaving of reinforcing yarn is a machine-dependent operation.
The cost of 3-D weaving is prohibitively high due to the weaving
machine cost. The composite product made from 3-D preform is
similar to an isotrophic material having good mechanical properties in all three directions.
8.3.4 Mechatronics
Composite parts for high-end applications (aircrafts, missiles, etc.)
in general are made in batches, so production rates are usually low.
Mechatronics is a semiautomated process for the design and fabrication of any product. As a result, this process may be used for the
manufacturing of composite products for high-end application. The
mechatronics process ensures high-quality products.
8.3 · Future Composite Manufacturing Technologies