4. Presentation of experimental
measurements results
When evaluating the acoustic load the method of
planned experiments was followed, by which experiments
for all combinations of levels of chosen factors were
realised, which enabled a description of describe the
structure of dependencies of the set of chosen evaluated
factors influencing noise of the production system with
AWJ (Figure 3b). For measuring of acoustic pressure
the exact modular noise analyser Investigator TM 2260 of
Brűel & Kjaer firm with a programme for noise analysis
was used, with linear measurement range adjustable in
the interval of 80 dB, which can be subtracted in full scale
from 70 dB to 130 dB after 10 steps. The measurements
were controlled manually in the time period 60 s from
the start of AWJ engagement, (Figure 3a). Experiment
measurement consisted of noise measurement of
background and environment, measurement of background
noise with turned on pressure device–Streamline SLII
pumping device and technological process measurement
according to experimental schemes. The influence of
particular factors on final value LAeq is shown in Pareto
graphs (Figure 4a, b). From the graph (Figure 4a), the
results that the biggest influence on the acoustic pressure
level LAeq in aluminium cutting of 10 mm thickness has
a regulated factor of feed speed v, (mm/min). Among
other factors partaking significantly in noise level are the
interaction of abrasive type mass flow ma (g/min) and feed
speed v, whereby their significance is increasing together
with the increasing speed, as it indicates the interaction
of feed speed v (mm/min) and lift x (mm).