Novel piezoelectric transducers to monitor head-disk interactions

As the flying heights of air bearing sliders are reduced to improve magnetic recording linear density, mechanical tolerances on the head-disk interface become more critical and real time measurement of wear-out phenomena becomes essential. We have developed novel piezoelectric techniques for monitoring contacts and mechanical resonances in the head-disk assembly. The techniques are real time and nondestructive, allowing use at the component level or in a fully assembled unit. Two sensor types will be described and data will be given for tests in which these sensors have been used to monitor flexure and suspension resonances, air bearing resonances, head-disk contacts, and disk roughness.