User`s manual
Section 6 – Systems Test
Dukane Part No. 403–556–03
Page 53
Overview
A Dynamic Process Controller (DPC) must be operating and connected
to the press/thruster in order to test the system.
For efcient operation of a Dukane ultrasonic assembly system, the
ultrasound signal from the Dynamic Process Controller must match the
frequency and phase angle (vibrational characteristics) of the stack that is
being driven. Each stack has unique vibrational characteristics dependent on
the combination of stack components. In addition, the characteristics of a
particular stack may vary slightly during operation because of temperature
and loading factors.
To match the DPC generator output signal with the characteristics of a
particular stack, the generator output frequency is adjusted by Dukane’s
patented Phase-Locked-Loop AUTO-TRAC Pulse-Width Modulation
circuitry.
The AUTO-TRAC feature automatically adjusts the ultrasound signal to
match the vibrational characteristics of the stack being driven. When the
ultrasound turns on during each operating sequence, the AUTO-TRAC
circuit monitors the motion of the stack on a frequency cycle-by-cycle
basis and adjusts the ultrasound signal for the optimum setting. Because
the AUTO-TRAC continuously monitors each operating sequence, it com-
pensates for vibrational changes that occur during repeated operations due
to heating of the stack components. It also compensates for changes that
occur over longer time periods due to aging of the piezo electric crystals
in the transducer, or possible wear of the ultrasonic horn.
The AUTO-TRAC feature excels in environments hostile to reliable
operation, such as high duty cycles or high stress, and continuous-duty
applications. In such situations, the AUTO-TRAC circuit compensates
for the unique vibrational characteristics of each stack due to differences
caused by aging, loading, temperature changes, and differences in horn
congurations.