The document discusses various methods for processing polymer matrix composites. It describes open molding processes like hand lay-up, spray-up, vacuum bagging, and filament winding which apply resin and fibers to a mold surface. It also covers closed molding processes like compression, injection, and pultrusion molding which use two-piece molds. Key factors in selecting a process include the materials, part geometry, and production quantities. Each method has advantages for different applications like boats, tubs, or structural panels.

1. PROCESSING OF POLYMER MATRIX
COMPOSITES
GROUP 4
NOORHAFIZAH BT MOHD YUSOFF
NUR AMIRA BT MAHMUD
NURUL FARAHAH BT ADENAN
FATIN NADZIRAH BT SABRI
SITI MUNIRAH BT ABD RASHID

2. MATRICES FIBRES COMPOSITE
MATERIALS

3. Polymer Matrix
Thermosetting (TS) polymers are the most
common matrix materials
Principal TS polymers are:
Phenolics – used with particulate reinforcing
phases
Polyesters and epoxies - most closely associated
with PMCs
Thermoplastic molding compounds include fillers
or reinforcing agents
Nearly all rubbers are reinforced with carbon black

4. MATERIAL SUITABILITY
Depending on the applications.
Not all materials are suitable for all
applications.
Knows the pros and cons of the materials
before using it for certain applications.

5. Factors to be consider :-
Structural (stiffness, strength, toughness)
Thermal
Electrical (conduct electricity or not ?)
Chemical (resistance)
Aesthetic (will the materials achieve the required
look?)

6. FACTORS IN PROCESS SELECTION
• Materials – matrix and reinforcing(fibres) system
• Reinforcing architecture required
• Complexity of part geometry
• Number to be manufactured
• How quickly they are to be manufactured

7. OPEN CLOSED
MOULDING MOULDING

8. Open Mold PMC Processes
1. Hand lay‑up
2. Spray‑up
3. Vacuum Bagging – uses hand-lay-up, uses atmospheric
pressure to compact laminate.
4. Filament Winding
 The differences are in the methods of applying the
laminations to the mold, alternative curing techniques, and
other differences

9. Open Mold Processes
Family of FRP shaping processes that use a single positive or
negative mold surface to produce laminated FRP structures
The starting materials (resins, fibers, mats, and woven
rovings) are applied to the mold in layers, building up to the
desired thickness
This is followed by curing and part removal
Common resins are unsaturated polyesters and epoxies, using
fiberglass as the reinforcement

10. Hand Lay‑Up Method
Open mold shaping method in which successive layers of resin
and reinforcement are manually applied to an open mold to
build the laminated PMC composite structure
Labor‑intensive
Finished molding must usually be trimmed with a power saw
to size outside edges
Oldest open mold method for PMC laminates

11. Hand Lay-Up Method
Figure 15.4 Hand lay‑up : (1) mold is treated with mold release agent; (2) thin gel coat (resin) is
applied, to the outside surface of molding; (3) when gel coat has partially set, layers of resin and
fiber are applied, the fiber is in the form of mat or cloth; each layer is rolled to impregnate the
fiber with resin and remove air; (4) part is cured; (5) fully hardened part is removed from mold.

12. Products Made by Hand Lay‑Up
Generally large in size but low in production quantity - not
economical for high production
Applications:
Boat hulls
Swimming pools
Large container tanks
Movie and stage props
Other formed sheets

13. SPRAY UP
Suitable in making boats, transportation components,
tub/shower units in a large variety of shapes and sizes.
Chopped laminated – good comfortability and faster than
hand lay-up.
Operator – control thickness and consistency
Operator dependant compared to hand lay-up.
Low production per volume but can produce more when
using multiple molds.

14. Spray‑Up Method
Liquid resin and chopped fibers are sprayed onto an open mold
to build successive FRP laminations
Attempt to mechanize application of resin‑fiber layers and
reduce lay‑up time
Alternative for step (3) in the hand lay‑up procedure

15. Spray-Up Method
Figure 15.5 Spray‑up method

16. Products Made by Spray‑Up
Boat hulls, bathtubs, shower stalls, automobile and truck
body parts, recreational vehicle components, furniture, large
structural panels, and containers
Movie and stage props are sometimes made by this method
Since products made by spray‑up have randomly oriented
short fibers, they are not as strong as those made by lay‑up,
in which the fibers are continuous and directed

17. Vacuum
Bagging
Use atmospheric pressure to suck air from under vacuum bag, to compact
composite layers down and make a high quality laminate (image from cgi.ebay.com).
 Layers from bottom include: mold, mold release, composite, peel-ply,
breather cloth, vacuum bag, also need vacuum valve, sealing tape.

18. Filament Winding
Resin‑impregnated continuous fibers are wrapped around
a rotating mandrel that has the internal shape of the
desired PMC product; the resin is then cured and the
mandrel removed
The fiber rovings are pulled through a resin bath
immediately before being wound in a helical pattern
onto the mandrel
The operation is repeated to form additional layers,
each having a criss-cross pattern with the previous, until
the desired part thickness has been obtained

19. Filament Winding
Figure 15.8 Filament winding.

20. Closed Mold Processes
Performed in molds consisting of two sections that open
and close each molding cycle
Tooling cost is more than twice the cost of a comparable
open mold due to the more complex equipment
required in these processes

21. Classification of Closed Mold
Processes
 Three classes based on their counterparts in conventional
plastic molding:
1. Compression molding
2. Transfer molding
3. Injection molding
4. Resin transfer molding
5. Pultrusion
 The terminology is often different when polymer matrix
composites are molded

22. Compression Molding PMC Processes
A charge is placed in lower mold section, and the sections are
brought together under pressure, causing charge to take the
shape of the cavity
Mold halves are heated to cure TS polymer
When molding is sufficiently cured, the mold is opened and
part is removed
Several shaping processes for PMCs based on compression
molding
The differences are mostly in the form of the starting materials

23. Injection Molding PMC Processes
Injection molding is noted for low cost production of plastic
parts in large quantities
Although most closely associated with thermoplastics, the
process can also be adapted to thermosets
Processes of interest in the context of PMCs:
Conventional injection molding
Reinforced reaction injection molding

24. Pultrusion Processes
Similar to extrusion (hence the name similarity) but workpiece
is pulled through die (so prefix "pul‑" in place of "ex‑")
Like extrusion, pultrusion produces continuous straight
sections of constant cross section
Developed around 1950 for making fishing rods of glass fiber
reinforced polymer (GFRP)
A related process, called pulforming, is used to make parts
that are curved and which may have variations in cross
section throughout their lengths

25. Pultrusion
Continuous fiber rovings are dipped into a resin bath and pulled
through a shaping die where the impregnated resin cures
The sections produced are reinforced throughout their length
by continuous fibers
Like extrusion, the pieces have a constant cross section,
whose profile is determined by the shape of the die opening
The cured product is cut into long straight sections

26. Pultrusion Process
Figure 15.11 Pultrusion process

27. Materials and Products in Pultrusion
Common resins: unsaturated polyesters, epoxies, and
silicones, all thermosetting polymers
Reinforcing phase: E‑glass is most widely, in proportions
from 30% to 70%
Products: solid rods, tubing, long flat sheets, structural
sections (such as channels, angled and flanged beams), tool
handles for high voltage work, and third rail covers for
subways.

28. Resin Transfer Molding (RTM)
intermediate volume molding process
inject resin under pressure into a mold cavity
can be automated and is capable of producing rapid cycle
times
Vacuum assist can be used to enhance resin flow in the mold
cavity.

29. resin is injected under pressure, using mix/meter injection
equipment, and the part is cured in the mold
The reinforcement can be either a preform or pattern cut
roll stock material

30. can be done at room temperature
produces parts with two finished surfaces.
laying up reinforcement material dry inside the mold, any
combination of materials and orientation can be used,
including 3-D reinforcements
Part thickness is determined by the tool cavity

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