Materials Testing Machine
Appendix:
16
012-13762C
Step Four
•
Click “Next” to open Step Four, “Record a smooth data run”.
“Seating” the Calibration Rod
Before
Recording Calibration Data
In the following procedure, the calibration rod is stretched and relaxed to remove the slack and properly “seat” the rod.
1.
Make sure that the Load Bar Round Nut is slightly loose and not applying a force on the calibration rod.
2.
Click “Record” and note that the Digits display shows the force on the load cell.
3.
Turn the crank clockwise about a quarter of a turn and note that the position and force data are being plotted on the Graph
display.
4.
Continue turning the crank clockwise until the force in the Digits display reaches the desired maximum (for example,
7000 N).
5.
Slowly turn the crank counter-clockwise and watch the Digits display. Reduce the force to between 10 N and 20 N (try not
to let the force go to zero.)
6.
Start turning the crank clockwise again to increase the force on the calibration rod as before. If the second plot “tracks” on
top of the first plot, slowly turn the crank counter-clockwise until the force on the Digits display is between 10 and 20 N.
Then, carefully increase the force to 100 N and click “Stop”. Do NOT change the crank position.
NOTE: Since the Materials Testing Machine will “auto-zero” when data recording starts again, the 100 N force is a “pre-load”
that results in better looking data.
Return to Step Four in the “Calibration” window
•
Click “Record” and collect a smooth run of position versus force data. When the data collection is finished, click “Stop”.
NOTE: A Polynomial curve fit is automatically applied to the run of position versus force data.
Figure: Step Four, Record a smooth data run
Position versus
force data