Air bearing force measurement of pico negative pressure sliders during dynamic unload

The air bearing forces of ''pico negative pressure'' (1.25 X 1.0 mm subambi ent pressure) sliders during the unload process were investigated experimen tally. A high speed vertical load/unload mechanism with a sensitive force t ransducer was developed to measure the air bearing forces. Force histories were measured at various disk rpm and unload velocities. The force historie s showed that the suspension load dimple separated from the load beam durin g the lifting. This separation was held to an acceptable amount by flexure limiters built into the suspension. Force-displacement curves show the need for control of the gap between the limitor and load beam. A technique was developed to determine critical suspension parameters for use in the CML Dy namic Load/Unload Simulator. Simulation of the force history was then in ex cellent agreement with experimental results, Both simulation and experiment al results showed that the lift-off force decreases with increasing disk rp m. Experimental results also showed that higher unload speeds lead to large r lift-off-forces. By selecting the correct disk rpm and unload speed, the lift-off-force could be minimized [S0742-4787(00)00103-X].