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QuintSonic 7
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b)
Using the table of literature values
The QuintSonic 7 menu offers two selection tables from which you can choose a sound velocity
according to the material to be measured.
In the table of ”literature values“ you will find a list of commonly used plastic materials and
other materials such as steel, brass, wood, etc.
Once you have defined a layer by selecting a material from the table, the calibration for this
layer is completed. Repeat this procedure for all layers of the layer system. Please note that
the values listed in the literature value table are average values only. Due to material
variations, the actual sound velocity of the material to be measured may deviate significantly
from the values indicated in the table.
c)
Using the table of „User values“
In this table you can define your own material / sound velocity combinations and define the
different layers of your layer system accordingly. Once you have defined the different layers
and their matching sound velocities, the calibration is completed. If the sound velocities have
been confirmed by reliable methods such as a material cross-
section, the “User values” table
represents an excellent method for a quick and easy calibration. However, it must be
considered that variations of raw material or batch-related product variations may be present.
For that reason it is recommended to verify regularly whether the sound velocities you have
defined in the table are still applicable for the material batch to be measured. If not, it is
recommended to make a cross section of the new material batch and use the calibration
standard resulting from this material cross section accordingly.
d)
Using the preset value for industrial coatings
The sound velocities for most industrial coatings are in the range of 2375 m/s ±15%.
If this default value of 2375 m/s is used for measuring industrial coating systems, as a
consequence, a maximum error of ±15% can be expected (the sound velocity will be included
in the calculation of coating thickness as a constant of proportionality). This is not good enough
for absolute measurements. For some applications, however, the main aspect is focussed on
keeping an absolute coating thickness constant that has previously been determined by
another measuring method (cross-section). In such case, the displayed absolute value has little
significance only. For that reason, it is recommended to carry out measurement on a reference
sample. The individual layers of this sample should represent the same thickness as the target
thickness to be expected. The displayed readings that to not match the actual coating
thickness, will be used as setpoint for the measurements to follow. All further measurements
will only provide the variations from the setpoint. This is important for process control, for
instance. In this connection, default sound velocities can be used to a limited extend only.
However, this does not represent a calibration in the strict sense. For the configuration of a
measuring series, QuintSonic offers to use the above value as a preset value.