DeFelsko PosiTector 100 v.4.0 - Manual (Page 28)

Page 28 100 Series
The thickness value was changed from 1.2 mils
to 1.4 mils. The sound velocity constant changed
from 86 to 100.81 mils/microsecond.
Notice the coating name automatically changed
from “Polymer” to “Polymer1”.
If the average is not within tolerance, optimize
the displayed value up(+)or down(-) to match
the check standard thickness using the
Setup
– Adjust Reading menu option. Measure
and adjust until you are satisfied that the
average of a series of readings equals the check
standard thickness.
Optionally if you know or have previously
recorded a sound velocity constant for this
material it may be adjusted instead of the
thickness value. For example the value for
the polystyrene probe tip is 80 mils per
microsecond. The value for the epoxy
coated metal Calibration Standards (pg.35) is 101.56 mils/microsecond. The
value for steel is approximately 250 mils/microsecond.
The Gage is now optimized for your coating. The sound velocity constant for
your material is shown in the upper right corner of the layer box. Normally, the
optimization process does not have to be repeated unless the coating material
changes. However it is a good idea to periodically re-measure the "check
standard".
Plastic Shims
A variety of colored precision plastic shims are included. They provide a quick
operational check of the Gage and help insure the operator is using it properly
by enabling them to practice various measuring techniques. Plastic shims are not
always manufactured with the same material. Therefore it is not important that
the Gage measure their exact thickness, rather readings should be consistent.
To measure shim thickness:
•
zero the probe using the
Setup q
q Zero Probe menu item (pg.29)
•
select the default coating “polymer” from the
Setup q
q Application
Setup menu item (pg.19). Select a substrate category of “none”
•
place a shim on any flat, hard surface. Apply couplant on top of the shim
and measure it.