Synergistic Approach to Abrasive Water Jet AWJ Process Understanding

1
Synergistic Approach to Abrasive Water Jet (AWJ)
Process Understanding
Botjan Jurievic, Andrej Lebar, Miha
Junkar University of Ljubljana, Slovenia

• introduction - AWJ characteristics
• benefits of process modelling
• new approach to proces modelling
• why synergistic approach
• model based on unit event features
• sound generation model
• synergism of weakly coupled models
• conclusions

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characteristics of the AWJ process

• the AWJ machining is a strongly non-linear
  process,
• the time constants depend on many parameters and
  disturbances,
• in the process many objects are involved,
• the process parameters are related with each
  other,
• the cutting tool is represented by a three phase
  turbulent flow jet with stochastic behavior.

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benefits of process modelling
"Science does not try to explain . It is mainly
building models. A model means a mathematical
construction which together with some verbal
interpretations give a description of the
observed phenomena. That mathematical
construction is merely and exclusively justified
because it is expected to work. John von
Neumann.

• due to the action of high velocity water jet only
  indirect measurements are possible,
• modelling is a tool for testing different process
  scenarios,
• to predict the results of AWJ machining process,
• to define the parameters for an optimal machining
• to control the AWJ process

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new approach to AWJ process
understanding
Gunasekara et al. 1982
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synergistic
action of one muscle induces several coordinated
actions
COOPERATION OF TWO OR MORE WEAKLY COUPLED SYSTEMS
A.M.Lebar. 1995
calculated
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existing AWJ models overview
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proposed AWJ model framework
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proposed model implementation
SIMULATION
SAE Al6061-T6

• AWJ machined surface and simulation result.
  Strong striation texture can be observed on both
  surfaces.

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sound generation model (awj)
theory
experiments
mechanisms of sound emission in the volume
between the AWJ collimating nozzle and the
workpiece
monitoring of sound and vibrations due to awj
cutting
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sound emission zones
in AWJ cutting

• AWJ cutting head
• volume within stand-off distance
• cutting zone
• awj exit point
• background noise

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model evolution
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how to achieve the synergism
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tuning of weakly coupled models
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abrasive grain rebound model
RMS of sound emitted in AWJ process
better process understanding