Metallurgy and Materials Engineering Department, University of Punjab Lahore

1. GROUP-H
NAVEED AHMED SIDDIQUI
(E12-318)
FAREED HUSSAIN QADRI
(E12-317)
MOAZZUM MAQSOOD
(E12-319)

3. OUT LINE
 INTRODUCTION
 MAJOR COMPONENTS
 HOW ULTRASONIC WELDING WORKS
 BASIC MOLECULAR PHYSICS
 SOLUTION OF PROBLEM
 ULTRASONIC WELDING OF PLASTICS
 APPLICATIONS OF UW OF PLASTICS
 USES OF ULTRASONIC WELDING
 LIMITATIONS OF ULTRASONIC WELDING
 CONCLUSION

4. INTRODUCTION
 One of the newest and most interesting fields of joining
technology is ultrasonic welding.
 In this process, high frequency vibrations are combined
with pressure to join two materials together quickly and
securely, without producing significant amounts of heat.
 These factors give it many advantages over traditional heat
based welding techniques.
 These include the ability to weld metals of significantly
dissimilar melting points.
 Finally, ultrasonic welds are made without consumables,
such as solder or filler that would ordinarily be used for the
connection and with far less energy usage than traditional
joining techniques

5. MAJOR COMPONENTS
 The system that is used to scrub the pieces together
consists of four major components.
Anvil
ultrasonic transducer
Booster
ultrasonic horn

7. IMAGES

8. COMPONENTS
ANVIL:-
This is simply a piece of the machine, usually with a
replaceable head, that holds one of the components
still while the other is rubbed against it.

9. COMPONENTS
ULTRASONIC TRANSDUCER:-
It is the “business end” of the ultrasonic system. This
component takes an electrical signal from a power
supply that is providing a 20khz AC signal and
converts it to a mechanical motion at the same
frequency. The vibration that results is at a frequency
that is appreciably above the range of human hearing,
hence the name ultrasonic.

10. COMPONENTS
BOOSTER:-
The next part of the system, appropriately called the
booster, increases the amplitude of the motion, at the
cost of some of its force. This motion is then passed to
the ultrasonic horn.

11. COMPONENTS
ULTRASONIC HORN:-
This is the portion of the system that actually vibrates
the work piece. In addition to providing the interface
between the ultrasonic generator and the work piece,
the horn also further amplifies the amplitude of the
motion, again reducing its force. Like the anvil, the
horn ends in a replaceable head.

12. How ultrasonic welding works
 The process of ultrasonic welding is fairly simple.
 It begins when the parts that are to be welded, such as
two multi-strand copper wires for example, are placed
together in the welding unit.
 The system then compresses the wires together with a
force of between about 50 and several hundreds
pounds per square inch to form a close connection
between the two pieces.
 Next, the ultrasonic horn is used to vibrate the two
pieces together at a rate of around 20,000 or 40,000
hertz, depending on the application.

13. BASIC MOLECULAR PHYSICS
 The first principal is that when two clean pieces of
metal are placed in intimate contact, they will begin to
share electrons, thus welding together.
 Second, at atomic scale even surfaces those that look
perfect and smooth are very rough and impure.
 The majority of this impurity is in the form of metal
oxides that were produced when the bare metal was
exposed to the atmosphere.

14.  The second part of the
contamination is in the form of
ordinary dirt and oils.
 These impurities form a layer
that prevents the electrons in
the two parts from passing
between them, thus preventing
them from welding together.
 In addition, the rough surface
prevents the metals from being
in intimate contact, which also
prevents the exchange of
electrons.

15. SOLUTION
 The ultrasonic welding process works by eliminating
these factors that prevent the pieces from being in
intimate contact.
 The vibration, combined with the pressure, first rubs
the impurities and oxides off of the surfaces of the
pieces where they are in contact.
 As the rubbing motion continues, the clean bare metal
parts are rubbed together, polishing them to a
molecularly smooth boundary.

16. SOLUTION
 When the ultrasound is turned off there is no longer
anything preventing the exchange of electrons
between the two perfectly cleaned and polished pieces.
Because of this the electrons begin to move between
them forming a true metallurgical weld.
 This entire process usually takes about one quarter of a
second.

17. FINAL JOINT

18. UW OF PLASTICS
 In addition to all of the uses of ultrasonic's in the
welding of metals, the technology can also be used to
weld plastic parts together.
 In this application, the process is slightly different
from that used to weld metals.
 One primary difference is that rather than scrubbing
the parts together, as in metal welding, in plastic
welding the parts are vibrated toward and away from
each other.
 This heats and softens them.

20. UW OF PLASTICS
 The continued motion then tends to mix the softened
surfaces of the plastic together, forming both a
physical, and if the plastics are selected correctly, a
chemical bond between the parts.
ADVANTAGES:-
Lower cost
Higher speed
Greater reliability than most or all other methods of
attaching the pieces.

21. UW OF PLASTICS
LIMITATION FOR PLASTICS:-
 The only restriction on welding plastics is that the
parts must have relatively close melting points, or else
one will melt completely before the other begins to
soften.

22. UW OF PLASTICS
APPLICATION:-
 Like ultrasonic metal welding, ultrasonic plastic
welding has a wide variety of uses.
 These include sealing containers and bags, attaching
plastic components and embedding metal
components in plastics.
 This last example deserves special attention.
 When a metal part needs to be attached to a plastic
part, convention methods include molding the metal
component into the part when it is created, gluing the
metal part to the plastic and locally melting the plastic
component then inserting the piece into the molten
area and allowing it to solidify.

23. UW OF PLASTICS
 Ultrasonic welding of metal to plastic works by using
the ultrasonic head to vibrate the metal component
against the plastic one. This heats and softens the
plastic part and allows the metal part to be inserted. As
the plastic cools, a very strong bond is made.

24. USES of ULTRASONIC WELDING
 Due to its versatility, effectiveness and cost, there are a
nearly infinite number of applications for ultrasonic
welding.
 One of the most common is for the production of
wiring connection.
 Ultrasonic welding is ideal for this application for a
number of reasons.
One of these is that it produces a nearly perfect
electrical connection.

25. Second, it requires no consumables, such as solder.
Third, it uses far less energy than other forms of
connecting, such as resistance welding, which is made
difficult by the excellent electrical characteristics of
copper wire.
Finally, the ultrasonic welding process produces little
heat, allowing it to be used near heat sensitive
components.

26. USES
 A subset of this field is the welding of enamel
insulated magnet wire to other wires or connectors. In
addition to the other advantages, the ultrasonic
scrubbing action effectively removes the insulation in
the normal process of making the weld, eliminating
the extra step of removing it that would be necessary
using other methods.

27.  Another common use of ultrasonic welding, also in
the electrical field, is joining aluminum wire, such as is
used in some transformers, to copper wire.
 In this case, ultrasonic welding is the only practical
method of performing the connection.
 Aluminum does not solder well, and attempting to
thermally weld aluminum to copper produces alloys
that are extremely brittle.
 Before the application of ultrasonic welding, the only
way to perform these connections was to first plate the
aluminum with nickel, then solder or weld to that.
This process was complicated and uneconomical.

28. USES
 Other applications include the
termination of both wires and pipes.
 Ultrasonic welding is well suited for
attaching terminations, such as clips or
other connectors to copper wires.
 Like joining wires together, this can be
done much more economically with
ultrasonic welding than with other
techniques.
 Finally, ultrasonic welding is often used
in HVAC industry, as well as others, for
sealing the ends of copper tubes.
 In addition to the usual advantage of
cost, ultrasonic welding is desirable for
this application due to its speed and
excellent reliability.

29. ADVANTAGES OF UW
 ultrasonic welding has many advantages over other
welding techniques for many types of connections.
 These include
Speed
Cost
reliability and many others.
 However, it should also be made clear that it is only
ideal for a relatively small proportion of all of the
possible joints.

30. LIMITATIONS
 There are some restrictions on the types of joints that
can be made with ultrasonic welding.
 One of these is that it is restricted primarily to
nonferrous metals and plastics.
 Another is that at least one of the parts must be
relatively light, as it would take a tremendous amount
of energy to vibrate a heavy part at the necessary
frequency.
 This restriction, unfortunately, limits the process to
small components and wires.

31. CONCLUSION
 It is one of the simple technique to weld the materials
either similar or dissimilar using vibration and friction.
So large amount of heat is not required in this
technique.
 Ultrasonic welding should not be seen as a
replacement for other techniques, such as GTAW,
resistance, laser, etc. but rather as an option in
situations for which it is well suited.

32. Reference
www.sonics.com

33. THANKS