This document discusses several common composite manufacturing processes. It describes open molding techniques like hand lay-up where reinforcement is placed in an open mold and resin is applied. It also discusses vacuum bag molding where layers are assembled and compressed using vacuum pressure. Other processes covered include filament winding, pultrusion, sheet molding compound, and resin transfer molding which injects resin into a closed mold. Each process is suitable for different part geometries and production volumes.

1. Composite Manufacturing Processes
Polymeric matrix composites

2. Composite Manufacturing Processes [cont.]
Open face molding
Hand Lay-Up
Oldest and most commonly used
manufacturing method
Usually used to produce polyester or
epoxy resin parts such as boat hulls, tanks
and vessels.
The method is quite simple, the resin
and reinforcement is placed against the
surface of an open (one sided) mold and
allowed to cure
A mold is coated by a release agent (wax)
after it was cleaned then dried thoroughly.

3.  Sufficient resin is spread in
the mold. A roller is used to
press each lamina in polymer
and to impregnate the fiber
firmly with polymer and
release voids.
 The laminate is leaved for 24
hour to dry
 The laminate is completely
cured at room temperature
after being removed from the
mould
Open face molding: hand Lay-Up (continued)

4. 2-Spray-Up
In the case of spray-up the
resin/reinforcement is sprayed
onto the mold with a spray gun.
A spray gun supplying resin in two
converging streams into which
roving is chopped
Automation with robots results in
highly increasing of production
where Labor costs are lower
Composite Manufacturing Processes [cont.]
Open face molding

5. 3-Filament Winding
 The filament is either pre-coated with the polymer or is
drawn through a polymer bath so that it picks up polymer on
its way to the winder. Wound around a rotating mandrel. Once
the resin has cured, the mandrel is removed, leaving the hollow
final product.
Composite Manufacturing Processes [cont.]
Open face molding

6. Types of filament winding
Polar winding
Helical winding
Circumferential winding
Composite Manufacturing Processes [cont.]
Open face molding

7. Advantages:
 High fiber volume fraction is obtained, about 60% to 80%.
 Long storage life
 Productivity is high (50 kg/h)
Disadvantages:
Expensive equipment, high cost for mandrel, poor surface finish.
Applications:
▫ Pressure tanks
▫ Fishing Poles
▫ Tennis rackets
▫ Rocket motors
▫ Shafts
▫ Oxygen bottles for firemen.
Advantages and disadvantages of filament winding
manufacturing process

8. To vacuum pump To vacuum Gauge
Breather/Absorption
Fabric
Peel ply
Sealant
tape
Vacuum
bagging
film
Laminate
Release
Film Release
coated mold
 First, apply a release agent (wax) to the mold avoiding that the edges of the mold
have no wax so the bag sealant tape (BST) will stick to the mold.
 The bag sealant tape is usually pressed on after the part is laid up, especially if it is
a wet layup.
 Then insert a peel ply to the laminate. Peel plies are a tightly woven fabric, often
nylon, and impregnated with some type of release agent. The peel ply will stick to the
laminate, but it will pull away without too much difficulty giving smooth surface.
After the peel ply comes a layer of release film. This is a thin plastic which has been
treated so it won't bond to the laminate. It is used to control resin flow It is highly
stretchable so it can conform to complex geometries.
Composite Manufacturing Processes [cont.]
Vacuum bag molding

9. At least one layer of breather (bleeder) cloth goes above the release
film. Bleeder is a thick, felt-like cloth. Its purpose is to absorb excess
resin and provide a continuous air path for pulling the vacuum. A
thick breather is also desirable to keep resin from coming in contact
with the bag.
The bag is the last item to be placed. It's a relatively thick plastic
layer. The bag is usually applied along one edge at a time. Start at one
corner and press the bag into the BST.
A vacuum pump is typically used to draw a vacuum.
Vacuum bagging is widely used in the composites industry as well.
Carbon and glass fiber, along with resins (epoxies) are common
materials laminated together with a vacuum bag operation.
Composite Manufacturing Processes [cont.]
Vacuum bag molding

10. Vacuum Infusion (VIP)
VIP is a technique that uses vacuum
pressure to drive resin into a laminate.
Once a complete vacuum is achieved, resin
is sucked into the laminate via carefully
placed tubing.
Once all the air has been removed from the
bag and the reinforcement has been fully
compressed under this pressure, liquid
epoxy resin (mixed with hardener) is
introduced to the reinforcement through a
pipe.
Any excess resin that is introduced will
eventually be sucked out into the vacuum
line. As a result, only the minimum amount
of resin is introduced. This lowers weight,
increases strength, and maximizes the
properties of fiber and resin.

11. Vacuum infusion provides a number of improvements
over traditionally vacuum bagging process as:
1) Better fiber-to-resin ratio
2) Less wasted resin
3) Save money
4) Unlimited set-up time
5) Cleaner
Composite Manufacturing Processes [cont.]
Vacuum infusion

12. • The term pultrusion combines the words, "pull" and "extrusion".
• Fibers are pulled through a resin bath (tank) where the fiber reinforcement
becomes fully impregnated (wetted-out) with the resin.
• The uncured composite material is guided to the performing die which helps
to arrange and organize the fiber into the correct shape, while excess resin is
squeezed out.
• Heated in a die with of final shape where the resin cured.
• Roll to finish and Cut to length
• Used for continuous shape structures (rods, beams, pipes, I-beams)
Composite Manufacturing Processes [cont.]
Pultrusion

13.  Structures are of high strength, corrosion resistant, non
conductive, have better thermal expansion than steel and
aluminum.
 Production rates around 1 m/min.
 Applications: sporting goods (golf club shafts), vehicle
drive shafts (because of the high damping capacity), and
structural members for vehicle and aerospace.
Composite Manufacturing Processes
Pultrusion

14. 1- Sheet molding compound (SMC)
Paste reservoir distributes an amount of specified resin paste onto a plastic
carrier film.
This carrier film passes under a chopper which cuts the fiber rovings onto
the surface.
Composite Manufacturing Processes
Matched die molding

15. Once these have drifted through to the
resin paste, another sheet is added on
top which sandwiches the fiber.
The sheets are compacted as they enter
onto rollers
The product can be stored as it
finishes.
The carrier film is then later
removed and the material is cut into
charges.
Heat and pressure act on the charge
and once fully cured, this is then
removed from the mould as the product
finished.
Composite Manufacturing Processes
Matched die molding
Application
Electrical applications, automotive.
 Corrosion resistant needs.

16. Matched die molding
2-Resin Transfer Molding
(RTM)
In the RTM process, the mold is
closed and the polymer matrix is
injected into the mold displacing
the air, once the matrix is cured
the part is ejected.
Resin content ~ (35-45)
vol%. Both thermoplastic
and thermosetting resins
are utilized: carbon, glass,
and aramid fibers are the
common reinforcements.

17. Resin transfer molding is a low pressure closed molding
process for moderate volume production quantities, and
the faster compression molding process
Multiple layers or plies complicate the resin distribution
Matched die molding
2-Resin Transfer Molding (RTM)

18. Advantages:
Complex components can be produced
Components have two good surfaces
Component can be created within a fairly tight tolerance
Process can be automated and repeated
Less material wastage
Labor savings
Disadvantages:
Higher tool Cost
Air voids are easily formed with poor process parameters
Applications:
 Car body, Aerospace structures, Helmets and Wind mills.
Matched die molding
2-Resin Transfer Molding (RTM)