Ultrasonic welding is an industrial process that uses high-frequency acoustic vibrations to locally weld workpieces under pressure. The process involves clamping plastic pieces in a fixture below an ultrasonically vibrating horn. Pressure and vibrations from the horn cause localized heating and plastic deformation at the interface, forming a strong weld. It is a fast, automated process that produces clean, precise welds without thermal damage, used for applications in automotive, medical, and other industries.

1. ULTRASONIC WELDING
Er. Sushant Bhatt, Lecturer, Deptt. Of Mechanical Engg. (IDS)
Email: sushantbhatt.ids@srmu.ac.in
Er. Arvind Verma, HoD, Deptt. Of Mechanical Engg. (IDS)
Email: hod.dip.me@srmu.ac.in
Shri Ramswaroop Memorial University, Barabanki, 225003

2. “Ultrasonic welding is
an industrial process
whereby high-
frequency ultrasonic
acoustic vibrations are
locally applied to
workpieces being held
together under
pressure to create a
solid-state weld.”
https://images.app.goo.gl/dSA4aEebyHhKTQMQ8
ULTRASONIC WELDING

3.  A Press: It is used to apply pressure on the two
plastic pieces to be joined. It may be of pneumatic
or electric driven type.
 Nest or anvil or fixture: It is a clamping device that
is used to hold and clamp the two plastic pieces
together.
 An Ultrasonic Stack: It consists of the three
components, a converter or piezoelectric
transducer, a booster and a horn or sonotrode.
These three elements are tuned to work on
resonate frequency of 15 kHz, 20 kHz, 30 kHz, 35
kHz or 40 kHz.
Equipment’s

4.  Converter: It converts the electrical signals into high-
frequency mechanical vibration and it does so through
the piezoelectric effect.
 Booster: It modifies the amplitude of vibration
mechanically.
 Horn or Sonotrode: It vibrates at high frequency and
transmits the mechanical vibration to the two pieces to
be welded. The horn is made of titanium or aluminium.
 An Ultrasonic Generator: It generates and delivers high-
frequency electrical signals matching the resonance
frequency of the stack.
 Controller: It is used to control the movement of the
press and delivery of the ultrasonic energy.
Equipment’s

5.  The two plastic pieces to
be joined are assembled in
the nest ( anvil or fixture)
 The horn is made to
contact at upper part of
the piece.
 A pressure is applied to
the two pieces against the
fixture. The pressure is
applied through the
pneumatic or electric
driven press.
Working Principle

6.  Horn is vibrated vertically
at very high frequency (20
kHz to 40 kHz), transmits
the mechanical vibration
to the two plastic pieces.
 It also create a localize
temperature rise due to
mechanical force and
friction.
 This heat helps in plastic
deformation at interface
and makes a strong joint .
Working Principle

7.  A clamping force is
applied to the two pieces
for a predetermined
amount of time to fuse
them together to form a
strong weld.
 After solidification, the
clamping force is removed
and horn retracted.
 The welded plastic part is
taken out of the fixture as
one piece.
Working Principle

8. Working Principle
https://images.app.goo.gl/gz1fKdjMWdKqEjyw6

9. Advantages:
 It is a fast welding process.
 It has Quick drying time i.e. the pieces do not
remain for a long time in the fixtures to dry
 It can be easily automated.
 It produces a clean and precise joint.
 It exhibits clean weld sites and does not
require and touch-up work.
 It produces a low thermal impact on the
materials.
Advantages and Disadvantages

10. Disadvantages:
 It cannot be used to produce large joints
(greater than 250 x 300 mm).
 It requires specially designed joints, so it can
make tip contact during the welding process.
 High tooling cost for the fixtures.
 The ultrasonic welding process is restricted
to the lap joints.
Advantages and Disadvantages

11.  This welding is used in fabrication of nuclear reactor
components.
 It is used in automotive industry for key, head lamp
parts, button and switches etc.
 Ultrasonic is used in electronic industries like
armature winding, switches etc.
 This is clean welding process so it is used in medical
industries to make parts like filters, masks etc.
APPLICATIONS

12.  A Textbook of Welding Technology by O.P. Khanna.
 Welding Science and Technology by Md. Ibrahim
Khan.
 https://www.theweldingmaster.com
 https://www.mech4study.com
 https://www.safetyandhealthmagazine.com
 https://images.app.goo.gl/TRh3g2CpTqKt4P7YA
References

13. THANK
YOU