Ultrasonic Plastic Welding
Prepared and presented By:
Dipal M.Patel
08PGME14
Guide By:
Mr. A.U.Rajurkar
Introduction
A solid state welding process in which coalescence
is produced at the faying surfaces by the
application of high frequency vibratory energy while
the work pieces are held together under moderately
low static pressure.
Ultrasonic welding, one of the most widely used
welding methods for joining thermoplastics, uses
ultrasonic energy at high frequencies (20 – 40 kHz)
to produce low amplitude (1 – 25 µ m) mechanical
vibrations.
The vibrations generate heat at the joint interface
of the parts being welded, resulting in melting of
the thermoplastic materials and weld formation
Lay-Out Of Ultrasonic
Plastic Welding Machine
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Second level
● Third level
● Fourth level
● Fifth level
Stages Of Ultrasonic
Welding
Introduction Of ABS Plastic
ABS - Acrylonitrile Butadiene Styrene
It is a copolymer made by polymerizing styrene and
acrylonitrile in the presence of polybutadiene. The
proportions can vary from 15 to 35% acrylonitrile, 5 to
30% butadiene and 40 to 60% styrene. The result is a
long chain of polybutadiene criss-crossed with shorter
chains of poly(styrene-co-acrylonitrile).
For the
majority of applications, ABS can be used between −25
and 60 °C as its mechanical properties vary with
temperature. The properties are created by rubber
toughening, where fine particles of elastomer are
distributed throughout the rigid matrix.
Properties Of ABS Plastic
Pleasing Surface
Density-1110 kg/m3
Good Chemical
Resistance,
Melt Temp (°C)- 211 to
261.
Good Impact
Resistance,
Low Shrinkage
Moisture Absorption
Low
Oil Resistant
Good weld ability
Good Corrosion
Application of ABS Plastic
Aerospace
Applications
Cell Phones
Coating Applications
Computer
Components
Containers
Cookware,
Microwave
Kitchenware
Prototyping
Telecommunications
Toys
Video Equipment
Camera Applications
Automotive Bumper
Automotive Exterior
Parts
Automotive
Electronics
Application
Literature Review
Process has had widespread industrial use in the last 25 year.
Most of the earlier studies authored by investigators in the
soviet union.
Much of published literature on ultrasonic welding is
qualitative , and it gives a good overview of ultrasonic welding
and its application.
Potente has studied various aspect of the process including the
longitudinal response of part to imposed vibration.
Benator studied theoretically and experimentally the ultrasonic
welding of thermoplastic.
Phase -1:-Design of Horn
A welding horn, also known as a sonotrode, is an
acoustical tool that transfers the mechanical
vibrations to the work piece, and is custom-made to
suit the requirements of the application.
The traditional methods for the design of an
acoustic horn are based on the equilibrium of an
infinitesimal element under elastic action, inertia
forces, and integration over the horn length to
attain resonance . Equilibrium leads to the following
differential equation:
Design of horn
Horns are designed as long resonant bars
with a half wavelength. By changing the
cross sectional shape of a horn, it is possible
to give it a gain factor, increasing the
amplitude of the vibration it receives from
the transducer – booster combination. Three
common horn designs are the step,
exponential, and catenoidal, as shown in Fig.
2.9 .
Step horns consist of two sections with
different
Design of horn
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Step horns consist of Second level
two
sections
with ● Third level
● Fourth level
different but uniform
● Fifth level
cross-sectional areas.
The
transition
between the sections
is located near the
nodal point. Due to the
abrupt
change
in
cross-section in the
nodal
plane,
step
horns have a very high
stress concentration in
this area and can fail if
Design Of Horn
Exponential horns have Click to edit Master text styles
Second level
a cross-sectional area ●
Third level
that
changes
● Fourth level
exponentially
with
● Fifth level
length.
The
smooth
transition distributes the
stress over a greater
length,
thus
offering
lower
stress
concentrations than that
found in step horns.
They
generally
have
lower gain factors, so
are used for applications
Design Of Horn
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Catenoidal horns are Second level
basically step horns with ● Third level
● Fourth level
a more gradual transition
● Fifth level
radius through the nodal
point. They offer high
gains with low stress
concentrations.
Design Of Horn
Material For Horn
Aluminium:Aluminium is a low-cost material which can be
machined easily, and which has excellent
acoustic properties. For these reasons, it is used
for welding large parts and to make prototype
horns or horns requiring complex machining.
Aluminium may be inappropriate for long-term
production applications due to its poor surface
hardness and fatigue properties .
Design Of Horn
Titanium:Titanium has good surface hardness and fatigue
strength and excellent acoustic properties. However, it
is very expensive and difficult to machine. Titanium
may also be carbide-coated for high wear applications.
Steel:Steel horns can only be used for low amplitude
applications due to its low fatigue strength. For severe
wear applications such as ultrasonic metal inserting
and welding glass filled materials, steel horns can be
satisfactory.
Phase-2:- Specimen
Preparation
Phase-3:-Experimentation
According to different parameter various in
the ultrasonic machine first of all consider
pressure effect on weld strength of the joint.
We will take reading at different pressure
values and test the welding strength of the
joint .
In Second stage consider the time effect on
the weld strength of the joint
In that we change the time of welding and
observe the welding strength of the joint.
Here , we also optimize the horn design by
varying different parameter.
Phase-4:-Validation with
FEA tools
For any experimentation work carried out by
anybody validation of that work is most
important phase for the experimentation .
Validation gives the proof of data and
result , which is carried out from
experimentation work.
For above all mention work we validate that
work with different FEA tools like, ANSYS 12.0
, Pro-engineering wildfire -4.
Phase-5-Report
Preparation
Last phase for any dissertation work is report
preparation.
Relevant Work On
Ultrasonic Plastic welding
Ultrasonic welding is used in almost all
major industries in which thermoplastic parts
are assembled in high volumes. Some
examples are as follows:
Automotive: headlamp parts, dashboards,
buttons and switches, fuel filters, fluid
vessels, seat-belt locks, electronic key fobs,
lamp assemblies, air ducts.
Electronic and appliances: switches, sensors,
data storage keys.
Medical: filters, catheters, medical garments,
masks.
References
1.
2.
3.
4.
5.
Troughton, M. J. “Handbook of plastics joining : a practical
guide” / M.J. Troughton. -- 2nd ed.
Ensminger D. and Stulen B. “Ultrasonic : Data, Equations, and
Their Practical Uses” CRC press
K.H.W. Seah, Y.S. Wong and L.C. Lee.“Design of tool holders for
ultrasonic machining using FEM” Journal of Materials
Processing Technology, 37 (1993) 801 816 Elsevier .
S.G. Amin, M.H.M. Ahmed, H.A. Youssef* “Computer-aided
design of acoustic horns for ultrasonic using finite-element
analysis machining” . Journal of Materials Processing
Technology 55 (1995) 254-260.
www.powerultrasonics.com