Performance requirements of microactuated suspensions in hard disk drives

The areal density of hard disk drives (HDDs) has been increasing more than the traditional annual growth rate of 60% in recent years. This has translated to a higher growth rate for radial density (track density) than for linear density (bit density). To enable reading from and writing on an extremely narrow track, the introduction of a microactuator has become eminent. There exist a number of different designs for microactuator applications, but the first version of microactuated suspensions introduced to the market has been those integrated with piezoelectric motors. To host these different types of microactuator materials inside hard disk drives, one needs to reevaluate the qualification criteria and establish new reliability measures. This paper provides the guidelines in setting the standards to meet the qualification requirements at the head-gimbal assembly and head-stack assembly levels.