The presentations helps us to understand about plastic welding and its different classifications. Further it gives a brief idea about the various industrial applications and latest developments in this field.

1. JYOTHI ENGINEERING COLLEGE, CHERUTHURUTHY
DEPARTMENT OF MECHANICAL ENGINEERING
19th January, 2017
Seminar on
PLASTIC WELDING
Seminar Guide Presented By
Mr. HAREESH N V PRAVEEN P
Asst. Professor JYANEME097
Dept. of Mechanical Engg.
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2. VISION
“To provide quality education of international standards in
Mechanical Engineering and promote professionalism with ethical values, to
work in a team and to face global challenges."
MISSION
•To provide an education that builds a solid foundation in Mechanical
Engineering.
•To prepare graduates for employment, higher education and enable a
lifelong growth in their profession.
•To develop good communication, leadership and entrepreneurship skills to
enable good knowledge transfer.
•To inculcate world class research program in Mechanical Engineering.
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3. TABLE OF CONTENTS
• Introduction
• Plastic Welding
• Classification of Plastic Welding
• Welding Rod
• Hot Plate Welding
• Hot Gas Welding
• Ultrasonic Welding
• Friction Welding
• Laser Welding
• Induction Welding
• Welding Temperatures and Welding Defects
• Applications, Advantages and Disadvantages
• Latest Advancement
• Conclusion
• References
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4. INTRODUCTION
• Plastics are typically organic polymers of high molecular mass
usually synthetic or semi-synthetic organic compounds that are
malleable and can be often moulded into solid objects.
• Plasticity is a property of all materials that are able to irreversibly
deform without breaking.
• Relatively low cost, ease of manufacturing, versatility and other
factors has already found many applications in the field of
automotive, medical, food, packaging etc.
• Best alternative for traditional materials like wood, stone, metal,
glass, ceramic, paper, leather etc.
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5. PLASTIC WELDING
• Plastic welding is the process of uniting softened surfaces of
materials, generally with the aid of heat.
• Welding can be used to produce bonded joints with mechanical
properties that approach to those of parent material.
• Thermoplastics like Polyethylene, Polypropylene, Polyvinyl
Chloride, Polyurethane and Acrylonitrile Butadiene Styrene (ABS)
are frequently used in plastic welding.
• Plastics that can be welded are called “thermoplastics” and when
they are heated to a sufficiently high temperature they will soften
and welded.
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6. CLASSIFICATION OF PLASTIC WELDING
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7. CLASSIFICATION OF PLASTIC WELDING
Welding process are categorized by the heating method that is used.
Two general categories are:
1. External heating
2. Internal heating
External heating:
• It rely on convection & conduction to heat the weld surface.
• Hot tool, hot gas, extrusion, implant induction, implant resistance
welding
Internal heating:
• It rely on conversion of mechanical energy into heat through surface
friction.
• Further divided into internal mechanical, Internal electromagnetic
heating
• Ultrasonic , Friction , Laser , RF welding.
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8. WELDING ROD
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A plastic welding rod, also known as
a thermoplastic welding rod, is a rod
with circular or triangular cross-
section used to bind two pieces of
plastic together. They are available
in a wide range of colors to match
the base material's color. Spooled
plastic welding rod is known as
"spline".

9. HOT PLATE WELDING
• It is the simplest of the mass production techniques to join
plastics.
• A heated plate is clamped between the surfaces to be joined until
they soften.
• The plate is then withdrawn and the surfaces are brought together
again under controlled pressure for a specific period.
• The fused surfaces are allowed to cool, forming a joint.
• The tool is often coated with non-stick material (Teflon) to act as
a release agent.
• Hot plate welding includes two kinds:
– High temperature hot plate welding.
– Non contact hot plate welding.
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10. • High temperature hot plate welding:
– The tool is not coated with release agent.
– The tool is heated to 300°C to 400°C.
– Once the parts are disengaged from the tool any residual material
is either oxidized away or mechanically removed.
• Non contact hot plate welding:
– the parts to be welded are bought near to the tool (1 to 3mm) and
convection and radiation heating from the tools heats the welding
surfaces.
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12. • Applications of hot plate welding:
– Polyethylene (PE) pipe welding for gas line installations.
– Fuel tank assemblies for the automotive industries.
• Limitations:
– One major limitation to hot plate welding is cycle time. A typical
cycle time is 0 to 30 seconds and larger with larger parts it can be
as long as 30 minutes
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14. HOT GAS WELDING
• This is similar to oxy-acetylene welding of metals. The only
difference is that the open flame of oxy-acetylene welding is
replaced by a stream of hot gas.
• Compressed air, nitrogen, hydrogen, oxygen or carbon
dioxide is heated by an electric coil as it passes through a
welding gun.
• The process, invented in the mid 20th century, uses a stream
of heated gas, usually air, to heat and melt both the
thermoplastic substrate material and the thermoplastic
welding rod.
• To ensure welding takes place, adequate temperature and
pressure must be applied to the rod, along with the use of the
correct welding speed and gun position.
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15. • Applications of hot gas welding:
– It is used for fabricate pipelines, pond liners, and a wide variety of
vessels.
– Used to join broken plastics easily.
• Advantages :
– Easy to use.
– Thermoplastics can be welded easily.
• Limitations:
– Slow manual process cannot be used in mass production.
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17. ULTRASONIC WELDING
• This method uses mechanical vibrations to form the joint. The vibrations
are of high frequency.
• The parts to be assembled are held together under pressure between the
oscillating horn and an immobile anvil and are subjected to ultrasonic
vibrations of frequency 20 to 40 KHz at right angles to the contact area.
• Alternating high frequency stresses generate heat at joint interface to
produce a good quality weld.
• ultrasonic welding is divided into two major groups:
– Near -field
– Far –field
• Near-field :
– The distance between the horn and the weld interface less than 6mm.
• Far-field:
– The distance between the horn and the weld interface is greater than
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18. 19/01/2017 Plastic Welding 18
Ultrasonic Welding Device

19. • Advantages:
– Used in mass production because the welding time are relatively
short.
– Applicable for both amorphous and semi crystalline thermoplastics.
– Used to bond dissimilar materials.
• Limitations:
– Horn size is limited to design constraints.
– The process and tools must be adapted to the materials to be
welded.
• Applications :
– Food packaging, computer components,
– Challenging and critical application is the standard disposable
butane lighter
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21. FRICTION WELDING
• The friction welding of thermoplastic is based on the same
principle as that employed for welding metals.
• In this process one of the substrates is fixed, while the other
is rotated with a controlled angular velocity.
• When the parts are pressed together, frictional heat causes the
polymer to melt and a weld is created on cooling.
• Major welding parameters include rotational speed, friction
pressure, forge pressure, weld time and burn off length
• There are four main variations :
– Linear welding
– Orbital welding
– Spin welding
– Angular welding
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22. • Advantages:
– The advantages of friction welding are high weld quality and the
simplicity and reproducibility of the process.
• Limitations:
– It is suitable only for applications in which at least one of the
components is circular and requires no angular alignment.
• Applications:
– Used to make thermoplastic manifolds for the automotive
industries
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24. LASER WELDING
• There are two modes of laser beam welding:
– Surface heating
– Through transmission infrared (TTIr) welding
• Surface heating:
– The surfaces of the components to be joined are heated by direct IR/laser
exposure for a sufficient length of time to produce a molten layer, usually for 2
to 10 s.
– Once the surface is fully melted, the IR/laser tool is with drawn from between
the parts, the parts are forged together, and the melt is allowed to solidify.
• TTIr welding:
– It is based on the concept of passing laser radiations through one of the
component to be welded while having the second component absorb the light at
the interface.
– This absorption results in heating and melting of the interface and allows the
parts to be welded.
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25. • Advantages of TTIr welding:
– It is a pre-assembled method.
– Speed and flexibility.
– It can also weld unsupported internal
walls with complex curvature if the
optical properties.
– Weld quality is very good.
• Limitations of TTIr welding:
– one of the component must be relatively
transparent to IR radiations.
• Applications:
– Brake fluid reservoirs, automotive
marking lights.
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26. INDUCTION WELDING
• Uses principle of electromagnetic induction.
• Contains an induction coil that is energized with a radio frequency
electric current.
• Main heating effect is resistive heating due to induced current also
known as eddy current.
• In joining plastics, an additional metallic or ferromagnetic material
is placed between the parts to be joined.
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27. 19/01/2017 Plastic Welding 27

28. Advantages:
• Strong and hermitic pressure tight joints.
• Multiple joints can be welded.
• Welded joints can be reopened for repair purpose and high
production rate.
Disadvantages:
• High Cost
• Additional work for preplacing implant.
• The presence of implant can sometimes affect the mechanical
performance of the joint.
Applications:
• Frequently used for welding large or irregular shaped parts made by
injection moulding, blow moulding, etc.
• Used in sealing plastic coated metal caps to plastic bottles, joining
of cross PE pipes, welding metal grills to the front of loud speaker
unit etc.
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29. WELDING TEMPERATURES OF
THERMOPLASTICS
Thermoplastics Temperature °C
ABS 350
ABS/PC 350
PA 400
PBT 350
PC 350
PE HARD 300
PE SOFT 270
PP 300
PP/EPDM 300
PUR 300/350
PVC HARD 300
PVC SOFT 350
XENOY (PC ALLOY) 350
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30. WELDING DEFECTS
Description Picture
The weld was started correctly but completed too quickly.
No wash indicates haste or too low a temperature.
The hot-air tool was not allowed to attain the correct
operating temperature.
The weld was finished too soon, leaving a hole.
Too much pressure has been applied to the rod leaving a low
and deformed bead.
Filling may be necessary
The welding temperature was too high, blistering the sides
of the weld.
The repair area may be brittle.
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31. MAJOR APPLICATIONS
(PVC, CPVC, ABS, LDPE, HDPE, MDPE, UHMW, PP, PPII (Copoly), PVDF, TPUR,
Xenoy, Acrylic, PC, Styrene, PEEK)
Aeronautics Agricultural Automotive Industrial
Interior Panels
Holding Tanks
Trays
Gaskets
PVC Fencing
Chick Hatchery Boxes
Tanks
Water & Misting
Lines
Fittings
Grills
Radiators
Battery Cases
Wheel Well Liners
Bumpers
Instrumentation
Panels
Truck Liners
Fan Housings,
Pails,Ductwork,
Flues,Plenums,
Screens,Displays,
Pipe, Fittings,Tanks,
Dampers,Storage
Tanks, Waste
Canisters,
Sinks,Dippers, Pans,
Stands,Filter
Housings, etc.
Marine Plumbing Other
Boats
Ballast Tanks
Fish Holding Wells
Fresh, Gray & Black
Water Holding Tanks
DWV Pipes
Pipes
Drains
Sinks
Faucets
Toys
Any thermoplastic
part
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32. ADVANTAGES AND DISADVANTAGES
Advantages Disadvantages
• Plastic welding generally does not
require intensive surface preparation
steps
• A weld is permanent, which prevents
tampering with the internal components
• Plastic welds are much lighter than
mechanical fasteners
• Welding can provide a leak tight, air
tight seal
• Welding works on a greater variety of
materials
• Advanced, modern equipment with
sophisticated control and monitoring
features
• Economical and fast process
• Plastic welding is highly dependent on
material compatibility
• Most welding processes required joint
designs which may be difficult to mold.
• Welding requires expensive assembly
equipment
• Thin walls tend to flex and deform,
which impedes welding
• Hot polymer melt often sticks to the
hot plate surface
• Need highly skilled and experts for the
operation
• Eye protection is mandatory for lasers -
safety precautions can significantly add
to cost of equipment
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33. LATEST ADVANCEMENT
TRANSPARENT LASER PLASTIC WELDING –
A REVOLUTIONARY STEP
• In the past welding clear polymers required special infrared
absorbers which were expensive and difficult to apply. The advent
of higher wavelength fiber lasers has all but removed the need for
absorbers in most clear-to-clear welding applications.
• In transparent laser plastic welding (TLPW) higher wavelength
lasers are used, which interacts differently with the plastic than the
typical 808nm or 980nm infrared lasers used in through-
transmission welding.
• Some of the laser energy is still transmitted or passed through a
clear thermoplastic, but at this wavelength some absorption is seen,
volumetrically, through the part. Enough volumetric absorption to
heat and plasticize the polymer.
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34. Hybrid welding combines laser energy with
infrared thermal radiation from conventional
halogen lamps. This increases the welding speed
whether the weld path is in two or three-
dimensions. The main application for this
technology is structural components in the
automotive sector, such as: automotive lighting
and motor assemblies.
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Clear Joining technology consisting of a laser
which is focused very precisely onto the joining
zone in the transparent material, where it then
transmits the highest energy input to create a
highly reliable weld. A special laser system, a
vision system, and the further advanced clamping
technology, ensure that this method is always
dependable and economic.

35. Applications:
• TLPW has huge potential in the medical device
industry where many devices are not only
clear/translucent, but also are required to meet strict
guidelines.
• Adhesives and solvents are the current method of
choice for bonding clear thermoplastics, but these
are often known to cause contamination or fail
regulatory testing. TLPW is clean, precise and
requires no additional chemicals or materials.
Implementation:
• The only major difference between TLPW and
regular through-transmission laser welding is the
laser source. This makes it very easy to implement
into the already existing modularized systems
designed for both automation and stand-alone
production environments.
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36. CONCLUSION
• Plastic welding is one of the most effective joining process of
plastics compared to other joining techniques like adhesives and
fasteners.
• Different types of plastic welding have been implemented
depending on the type of materials and all of them works on similar
working principle.
• Recent advancement in this field is conquering the peaks and results
in the innovative techniques like TLPW and future explorations are
running in its course that will help to uplift the field of medical,
automotive and other industries.
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37. REFERENCES
[1] S.Harikannan, et.al (2015), “Fabrication and Analysis of Thermo
Plastics Welding”, International Journal of Innovative Research in
Science, Engineering and Technology
[2] A. B. Humbe, et.al (2014), “Review of laser plastic welding
process”, IMPACT: International Journal of Research in Engineering &
Technology (IMPACT: IJRET)
[3] D. Grewell, et.al (2007), “Welding of Plastics: Fundamentals and
New Developments”, Intern. Polymer Processing XXII
[4] Anahi Pereira da Costa, et.al (2012), “A Review of Welding
Technologies for Thermoplastic Composites in Aerospace
Applications”, J. Aerosp. Technol. Manag., Sao Jose dos Campos,
Vol.4.
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38. THANK YOU
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