AN INVESTIGATION OF THE TAKE-OFF CHARACTERISTIC OF TRI-PAD SLIDERS USING PHASE DEMODULATED LASER INTERFEROMETRY

The interaction between a tri-pad slider and a rigid disk during ''tak e-off'' is characterized using phase demodulated laser interferometry and acoustic emission (AE). A double peak was observed in the AE signa l during the ''take-off''. A biquadratic surface fit for the air beari ng surface was used and it was found that the transition between the f irst peak and the second peak corresponds to a change in contact locat ion from the rails to the tri-pad of the slider. The second peak is sh own to correspond to a change in contact location from the leading to the trailing edge of the third pad. As the disk linear velocity increa ses, the tri-pad slider increases its pitch angle, but remains in cont act with the disk, pivoting on the trailing edge of the tri-pad.