Pultrusion is a continuous manufacturing process for composite materials with constant cross-sections, utilizing essential components like fiber creels, resin impregnation systems, and hot dies. It allows for the production of complex shapes but primarily accommodates constant cross-sectional profiles, presenting some disadvantages, such as limitations on fiber orientation control and susceptibility to voids if improperly managed. The process is cost-effective compared to some other methods but requires a significant initial investment and has varying production speeds based on shape complexity.

1. PULTRUSION
Presented by,
ROLWYN MARIAN CARDOZA
1RV18MMD15
MTech MACHINE DESIGN
RV COLLEGE OF ENGINEERING.

2. What is
‘PULTRUSION’ ?
Pultrusion is a continuous process for
manufacture of composite materials
with constant cross-section.
PULTRUSION = PULL + EXTRUSION

3. IMPORTANT COMPONENTS OF
PULTRUSION PROCESS
1. Fiber Creels
2. Resin impregnation
systems
3. Preformer
4. Hot dies
5. Pulling mechanism
6. Cut off saws

4. CREEL
A rack holding cylinder or cone
holding threads or spools when
spinning.

5. RESIN IMPREGNATION SYSTEM
It allows the reinforcement
travelling from the creels
down into the bath and the
resin coated fibers comes out
through a guided bar.

6. PREFORMER
Preform plates are critical component of
pultrusion system as it properly aligns
and feeds the reinforcement to the
heated die.

7. HEATING DIES
The main component of any
pultrusion system where part to be
produced is given shape and is
cured.
Heated dies are often about 1 m
long, there is sufficient time to fully
cure the resin.

8. PULLING MECHANISM
Pulling system pulls the
product from the heated
dies on a continuous basis.
Generally, a caterpillar belt
is used in the pulling
system.

9. CUT OFF SAW
The last unit of pultrusion
system is cut off saw which
cuts the pultruded product
in desired size.
Flying type of cut off saws
commonly used.

10. RAW MATERIALS USED IN THE PULTRUSION
SYSTEM
 Reinforcing materials :
Glass (E-glass and S-glass), Carbon , Aramid fibers in the
form of roving strands, mat (continuous filament mat,
chopped strand mat) and fabrics.
 Veils
 Matrix materials:
Unsaturated polyester, epoxy, vinyl ester resin and
phenolic resins are used.

11. CHARACTERISTICS OF PULTRUSIONS
 Volumes of production :
Depends on the size and complexity of the shape. 500 metres is a typical
minimum run.
 Unit price vs capital investment :
The cost is lower than that for some moulding processes such as injection and
compression, but higher than for, hand lay-up moulding.
 Speed :
Depends on size, but as a rule of thumb it is possible to achieve 0.5 metre per
minute for a profile measuring 50 by 50 millimetres, 0.1 metre per minute for chunky
shapes and 1 metre per minute for narrower sections.
 Surface :
The surface finish can be controlled to a degree, depending on the
reinforcement and polymer.

12.  Types/complexity of shape
There are no problems with undercuts in pultrusion. Virtually any type of
shape that can be squeezed through the die can be made, bearing in mind that the
shape must have a constant thickness.
 Scale
The maximum size for profiles is typically 1.2 metres wide, although there are
specialist machines that make larger components. Minimum wall thickness is
approximately 2.3 millimetres. The size of the manufacturing plant dictates the
limit to the length of the pultrusion.
 Tolerances
Vary depending on the profile, but on a standard box-section, with a wall
thickness of 4.99 millimetres, the tolerance is ±0.35 millimetre.

13. DISADVANTAGES OF PULTRUSION SYSTEM:
 The process is mainly suitable for constant cross sectional areas. Tapered
and complex shapes cannot be produced with this method.
 Control of fiber orientation is not possible in the pultrusion system.
 Quick curing resin systems typically have lower mechanical properties.
 Voids may result in parts if excessive opening given at die entrance.
 High initial investments.