Section No.
Reference No.
OPERATION & MAINTENANCE SPECIFICATIONS MANUAL
09
07
Section:
Subject:
EQUIPMENT/TOOLS
ULTRASONIC THICKNESS MEASUREMENT
Procedure Issue Date: February 2007
Revision
2
Approved by:
Page 4 of 10
U
P
3.
Material Calibration to Known Thickness
The following procedure is used to calibrate the T-Mike E sound velocity to a known sample of material.
Some materials may exhibit sound velocity variations which can cause errors in measurement. Be sure to
check a representative group of samples to determine if such variation is present.
First follow the above PROBE ZERO procedure (step 2) to calibrate the delay of the ultrasonic transducer
being used.
Apply a drop of couplant to the representative piece of material of known thickness. This piece is called
the sample.
Place the probe in steady contact with the surface of the sample. The T-Mike E will display a thickness
reading using the last calibrated velocity.
Press the CAL key (item 9 in Figure 2) to lock in the reading. The transducer may now be removed from
the sample. The display on the T-Mike E will momentarily display CAL. Small arrows will appear in the
upper left portion of the display above the thickness readings. This indicates that the T-Mike E is in the
calibration mode and enables the UP/DOWN arrow keys.
Adjust the thickness shown on the T-Mike E display by using the UP and DOWN arrows
(item 10 in Figure 2). Note that when these keys are held continuously, the speed at which
the thickness changes will increase, making it easy to make the large adjustments for
materials such as plastic and aluminum.
When the correct thickness appears on the display, press the CAL key again to display the sound velocity
of the calibrated material as calculated by the T-Mike E. The display of sound velocity will be indicated by
the appearance of appropriate velocity units (IN/ms or M/S) above the displayed velocity value. Press
CAL key one final time to accept this sound velocity and return to the measurement mode.
Check the calibration by replacing the probe on the sample piece. The T-Mike E is in the CALIBRATION
mode the unit will not make further measurement until the calibration procedure is completed.
4.
Calibration from Known Velocity
The following procedure is used to calibrate the T-Mike E to a given material velocity.
Follow the above PROBE procedure to calibrate the delay of the ultrasonic transducer being used.
Press the CAL key (item 9 in Figure 2). The arrow symbols will appear in the upper left portion of the
display indicating the UP/DOWN arrow keys are active.
Press the CAL key a second time. The display on the T-Mike E will display the current velocity and the
appropriate units of measure.
