http://www.spiratex.com/ : Understand the complete process of custom plastic extrusion with step by step details of the process through this presentation. It also explains the various specialized forms of plastic extrusions.

1. Understanding Plastic Extrusion
The Spiratex Company | 6333 Cogswell Rd, Romulus, MI 48174 | 734-992-7229

2. Importance of Plastic Extrusion
Use of plastic has increased manifold in the daily life. Either it is for packing
food material or soft drinks or for industrial piping and other uses, plastic is
used extensively in all sectors. Plastic can be given various shapes and sizes
conforming to your specific requirements using the plastic extrusion method.
This has turned very advantageous for industries as they put great emphasis
on consistency of the shape, size and quality of the product.

3. Plastic extrusion process involves melting plastic and giving it various shapes
by forcing it into various dies to give shape of continuous of continuous profiles.
This is then cut to various sizes.
Using plastic extrusion process we can get final product with constant cross
sections which are perfect for industrial use. Plastic extrusion is a great way of
achieving standardized sizes which are easily workable.
…Importance of Plastic Extrusion

4. …Importance of Plastic Extrusion
• Plastic extrusion is the best way to make low cost plastic products at a faster
pace and hence it yields greater productivity too.
• Plastic extrusion method is used for manufacturing products such as piping,
plastic sheets, weather stripping, wire insulation tapes, adhesive tapes, etc.

5. Requirements
Plastic extrusion can be carried out with the help of a simple plastic extrusion
machine. The main components of the plastic extruder machine are hopper,
barrel, screw drive, and the screw drive motor.
Thermoplastic material is the basic raw material used for the plastic extrusion
process. It is used in the resin form which is easy to for loading and melting.

6. … Requirements
The most common materials used for this procedure are high impact
polystyrene (HIPS), PVC, polyethylene, polypropylene, and ABS.
For getting the final desired result or dies are used. Dies are prepared
specifically as per the requirement of the shape or size of the final product. The
accuracy of the die would decide the finish and consistency of the final product.

7. The Process
The resins are put in the
extruder’s hopper and it is
ensured that they contain the
proper additives required for
the work. In case it lacks
proper additives then additive
such as UV inhibitors, anti-
oxidants, or colorants are
also added with the resins
1

8. …The Process
These resins are then
passed on to the extruder
barrel through the feed
throat of the hopper. The
barrel has a long rotating
screw that forces the
resins towards the die.
2

9. …The Process
The resins are subjected
to extremely high
temperature and pressure
in the barrel where they
start to melt which is
necessary to give them
the required shape.
3

10. …The Process
The temperature in the barrel
can range between 400-530
degrees Fahrenheit. Most of
the barrels have the settings
which provide increasing
temperature at the farther
end so that degradation of
the plastic can be controlled.
4

11. …The Process
Once the molten plastic reaches the
end of the barrel it is forced through a
screen pack and then fed into feed
pipe which leads to the die. The
screen pack serves as a filtering
medium where the contaminants in
the molten pipe are removed. The
number of screens, its porosity and
other factors ensure that the right kind
of material under the required
pressure is attained which can be put
to the die.
5

12. …The Process
The molten plastic is then put
into the dies where it cools off,
hardens and attains the required
shape. For expediting the
cooling process the newly
formed plastic is given sealed
water bath. For plastic sheeting
extrusion cooling rolls are used
in place of water baths.
6

13. Importance of Maintaining the Temperature
Temperature plays a very
important role in plastic
extrusion process. Maintaining
the correct temperature level
and melting rate is very
important for smooth fluidity of
the plastic resins. It is important
for minimizing problems like
stress and wrapping of the final
product.
Monitoring of heaters is very
important as they need to be
lowered, raised or shutoff as per
the temperature requirement
from time to time. Cooling fans
and cast-in heater jackets also
play a very important part in
attaining the required extrusion
temperature.

14. Screw Design- An Important Consideration
Screw is the only moving part in the plastic extruding procedure and hence
various factors like melting rate, size of the resin, type of raw plastic, and
amount of pressure required maintaining uniformity, etc. play an important part
in deciding the size, design and diameter of the screw.
Few applications in which materials need to be compounded within the barrel of
the extruder a twin screw design may be used for adequate mixing.

15. Some Specialized Extrusion Procedures
One solution fits all can never be fit for industrial purposes as every process
has a definite set of requirements. Some specialty extrusion processes are
explained ahead

16. …Some Specialized Extrusion Procedures
Blow Film Extrusion
This is a process ideal for fabricating plastic films
such as grocery and food storage bags.

17. …Some Specialized Extrusion Procedures
Coextrusion
This process is used for extruding several layers
of material at the same time. This may require
two or more extruder feeds feeding different type
of material at the same into a single extrusion
head.

18. …Some Specialized Extrusion Procedures
Overjacketing
This is used for coating a material with plastic. It
is commonly used for exterior wire or cable
jacketing.

19. …Some Specialized Extrusion Procedures
Tubing Extrusion
This is used for making plastic tubes. The
process is similar to plastic extrusion just pins or
mandrels are used in place of dies for producing
hollow plastic tubes.

20. …Some Specialized Extrusion Procedures
Injection Molding
In this process the molten plastic is injected into
the mold which is then allowed to cool and attain
the required shape.

21. …Some Specialized Extrusion Procedures
Blow Molding
This is a process used for manufacturing hollow
objects such as plastic bottles and containers. In
this process after injecting the plastic hot air is
blown in the mold with pressure so that the
plastic attains the required shape.

22. …Some Specialized Extrusion Procedures
Thermoforming
This is the process of giving the required shape
to plastic sheets by applying high temperature
and pressure.

23. The Spiratex Company
The Spiratex Company is a leader in custom
plastic extrusion, serving customers with
production facilities in Romulus and Monroe,
Michigan. As apioneer in the extrusion
process for UHMW/PE, The Spiratex
Company has set industry standards for the
global extrusion marketplace.
Visit www.spiratex.com to learn more about
The Spiratex Company or to request a free
estimate.