THE DEPENDENCY OF TAKEOFF VELOCITY AND FRICTION ON HEAD GEOMETRY AND DRIVE CONFIGURATION

Wear at the head-disk interface of magnetic recording devices is depen dent on the contact sliding distance between the head and disk. The sl iding distance is dependent on the head takeoff velocity and frictiona l drag. In this study, the dependence of takeoff velocity and friction on selected head parameters was measured with an air bearing spindle equipped with a strain gauge. For the thin film head, crown had the gr eatest influence on takeoff velocity, folio wed by bolt pattern runout , suspension preload, camber, skew angle, and rail width in decreasing order. For the metal-in-gap head, ski jump had the greatest influence . The rest of the parameters followed in the same order as they did fo r the thin film head. Twist and edge blend did not affect takeoff velo city, but larger edge blends did improve contact start-stop performanc e. Lower mass disk stacks did better in contact start-stop tests becau se of their shorter sliding distance before reaching the takeoff veloc ity or after achieving the landing velocity. Finally, both crown and s kew angle affected the coefficient of friction between the head and di sk. Heads with a more positive crown or zero skew angle had the lowest coefficient of friction.