Real-time underwater abrasive water jet cutting process control
Invited paper
Katholieke Universiteit Leuven
Tuesday 2 june, 2015, 14:00 - 14:20
0.8 Rome (118)
Abstract:
The underwater cutting of large steel structures is a cumbersome process.
There is no directly applicable method for the real-time control of abrasive
water jet cutting quality. However, for some applications where structures
have to be separated by means of underwater cutting, an adequate process
monitoring strategy is indispensable.
This paper describes how two related methods are used for indirect cutting
process monitoring. One method uses a real-time time and spectral analysis
of
the emitted sound of the abrasive water jet while the other method monitors
the resonant structural behaviour of the structure during the cutting
operation.
The first section of this paper focusses on the main parameters of an
abrasive
water jet cutting process and their influence on the resulting sound
spectrum
of the jet. An overview of the currently applied monitoring methods is
given.
A second part relates the emitted sound spectrum of the abrasive water jet
with its possible disruptions or irregularities during cutting. It is fully
outlined how adequate experiments are used for this analysis.
The third section analyses the structural resonant behaviour of simple tubes
during cutting. It is outlined how real-time vibration monitoring helps to
estimate the degree of separation during a typical cutting operation and the
remaining defects after a cutting process.
Finite elements models are applied to determine the optimal measurement
configuration for this vibration monitoring. Simulations are validated by
means of lab-scale experiments. Special attention is given to the spatial
resolution that can be reached by this method and a discussion of its
advantages and limitations.
Section four describes the validation of both methods during an industrial
under water abrasive water jet cutting process. It summarizes with general
conclusions on the application of both methods.