ULTRASONIC WELDING PROCESS FOR ADVANCED WELDING TECHNOLOGY

Ultrasonic welding process

1. ULTRASONIC
WELDING
ADVANCED WELDING TECHNOLOGY
18PPE708
AISHWARYA ARUL ABIRAMI K
71772115106

2. Introduction
ULTRASONIC WELDING
•Uses Ultrasonic waves or vibration
•The frequency is generally above the normal hearing
frequency
•Frequency ranges between 20,000Hz to 30,000Hz
•It is a solid state welding processes
•No external heat is added for welding
DEFINITION : A solid state welding process in which
coalescence is produced at the faying surfaces by the applications of
high frequency vibratory energy while the workpieces are held
together under moderately low static pressure

3. PRINCIPLE
In ultrasonic welding, frictional heat produced by the ultrasonic waves
and force is used for the joining process.Ultrasonic waves (15 to 60
kHz) are transferred to the material under pressure with a sonometer.
Welding times are lower than 3s. The welding can proceed with or
without the application of external heat.
In ultrasonic welding, frictional heat produced by the ultrasonic waves
and force is used for the joining process.
Ultrasonic waves (15 to 60 kHz) are transferred to the material under
pressure with a sonometer. Welding times are lower than 3s. The
welding can proceed with or without the application of external heat.

4. Equipment’s
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.

5. Equipment’s
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.

6. Working:
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 .
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.

7. Working
..

8. 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.

9. 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.

10. Applications
*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.

11. Thank You..