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2.5
Welding Systems
Ultrasonic Plastics Welding
Thermoplastic parts are welded ultrasonically by applying high-frequency vibrations to the
parts being assembled. The vibrations, through surface and intermolecular friction,
produce a sharp rise in temperature at the welding interface.
When the temperature is high enough to melt the plastic, there is a flow of material
between the parts. When the vibrations stop, the material solidifies under pressure and a
weld results.
The Plastics Welding System
The 2000X Micro welding systems consists of a power supply, a Micro Actuator, an
Interface Box, and a converter-booster-horn stack. The system can perform a variety of
ultrasonic welding operations, including: staking, spot welding, swaging, degating, and
continuous operations. It is designed for use in automated, semi-automated, and/or
manual production systems. Contact Branson for continuous operations or high duty
cycles.
Power Supply
The 2000X distance digital Power Supply converts conventional 50/60 Hz line current to
high frequency electrical energy. It also contains all the electronic controls and can be
located remotely from the Actuator and Interface Box. This allows the operator to adjust
or reprogram the welding cycle remotely from the Actuator and related welding, tooling,
and parts-handling systems.
The 2000X distance Power Supply also contains a DC power supply for electrical power to
operate the electrical components and control circuits in the power supply, Interface Box
and on the Actuator.
Converter
The converter is mounted in the actuator as part of the ultrasonic stack. The ultrasonic
electrical energy from the power supply is applied to the converter (sometimes called the
transducer). This transforms the high frequency electrical oscillations into mechanical
vibrations at the same frequency as the electrical oscillations. The heart of the converter
are piezoelectric ceramic elements. When subjected to an alternating voltage, these
elements alternately expand and contract, resulting in better than 90% conversion of
electrical to mechanical energy.
Booster
Success in ultrasonic assembly depends on the right amplitude of movement at the horn
face. Amplitude is a function of horn shape, which is largely determined by the size and
form of the parts to be assembled. The booster can be used as a mechanical transformer
to increase or decrease the amplitude of vibrations applied to the parts through the horn.
The booster is a resonant half-wave section of aluminum or titanium. It is mounted
between the converter and the horn, as part of the ultrasonic stack. It also provides a
clamping point for rigid stack mounting.
Boosters are designed to resonate at the same frequency as the converter with which they
are used. Boosters are usually mounted at a nodal (minimum vibration) point of axial
motion. This minimizes the loss of energy and prevents vibration from being transmitted
into the actuator.
100-412-182 REV. 06
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