1) Apparatus: Mullen Tester, based on Tappi Method T 403.
2) Turn on power of control panel and motor.
3) Place the handsheet semi-curve piece over the diaphragm, making sure that the area of testing is well away from the edges. You must perform two tests per sheet so leave enough room for a second burst test. Lock it into place by sliding down the aluminum ring at the compressed air inlet, the plunger engages (see figure 10). Press METER RESET to zero value. If it is not exactly zero, Switch the TEST MODE to TRACK then turn the ZERO knob to bring the reading to 00.0. Switch the TEST MODE back to PEAK. Press METER RESET again. Turn the red needles of pressure gauges to 0.
4) Pull the level bar to the START. When the sheet bursts, pull the level bar to the REVERSE until the diaphragm deflates then bring the level bar to the middle. Record the burst value and check the value of control panel and the gauge positions.
Figure 10: Engage the clamp to hold the test piece in place for the first burst.
5) Release the plunger by pulling up the aluminum ring, then flip the semi-curve piece over and repeat the above steps. Adjust the position of testing area so there is no clamp mark within it. Overall, there will be 5 readings on smooth side and 5 readings on rough side (see figure 11).
Figure 11: Flip the test piece to carry out second burst test on the other side.
6) If your results drift away from the normal range, please check the quality of handsheets and ZERO setting first. If nothing is wrong with handsheets and machine setting, please call Lab Manager to carry out calibration check.
