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Why use ultrasonic welding?
Ultrasonic welding is used for the assembly of thermoplastic material or the assembly of nonthermoplastic
material to thermoplastic material by means of insertion or staking. The process is a much faster and
safer alternative to using solvents or heat as a bonding method. Ultrasonic welding is used by automotive,
medical, toy and many other product manufacturers that use plastic for their product material.
How does ultrasonic welding work?
Ultrasonic welding is the conversion of high-frequency electrical energy to high-frequency mechanical
energy. This mechanical energy is a vertical motion in excess of 15,000 cycles per second. When this
vertical, vibrating motion is transferred to a thermoplastic material under pressure, frictional heat
is generated at the interface, or joints, of two pieces of thermoplastic or with a metal and
thermoplastic. This conversion process is done through an ultrasonic welder properly tooled with a horn
and fixture. (See illustration above.) The welder's power supply converts standard 60 hz alternating
current to frequencies of 15,000 hz, 20,000 hz, or 40,000 hz, depending on which welder you own. This
alternating current enters the convertor where it is converted to vertical, mechanical motion equal to
the alternating current - 15,000, 20,000 or 40,000 vertical cycles per second. This vertical motion
comes out the other end of the converter, passes through a booster which can increase the amplitude of
the vibrating motion, and is then passed to the horn which transfers the mechanical energy to the parts
that are being welded. The parts that are being welded are secured in a fixture which holds the parts
in place and square to the horn. This is just a brief overview of the ultrasonic welding process.
Many variables in amplitude, weld time, pressure, horn design, fixture design and joint design need
to be considered in order to achieve successful plastic assembly. Toman Tool Corporation's engineers
have over 50 years of combined experience in working with these plastic assembly challenges.
They are always eager to find solutions to new plastic assembly applications.
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