Various illustrative aspects are directed to a data storage device comprising one or more disks; an actuator arm assembly comprising one or more actuator arms, and configured to position the one or more actuator arms over disk surfaces of the one or more disks; one or more fine actuators, disposed on the one or more actuator arms; and one or more processing devices. The one or more processing devices are configured to: output a driver current to the one or more fine actuators, wherein the one or more processing devices are configured to rate limit a rise of the driver current over time during an activation of the driver current to within a selected rate limit of current rise over time.

A suspension assembly includes a support plate, a wiring member, and a driving element. The wiring member includes a metal plate, an insulating layer, and a conductive layer. The metal plate includes a base end plate, a support portion on a projection portion formed on the support plate, and a pair of link portions which connect the base endplate to the support portion. The insulating layer includes a first end portion on the support portion, and a pair of bridge portions which are respectively provided in parallel with the link portions and extend from a second end portion that is on the base end plate to the first end portion. The driving element deforms in response to a voltage applied thereto to move the support portion. Each link portion includes a bent portion at a location of a straight line passing through a central region of the driving element.

A flexure assembly is described. The flexure assembly includes a gimbal portion on configured to receive a slider. The gimbal portion includes a first surface and a second surface which is opposite to the first surface. The slider is mounted on the second surface. The flexure assembly also includes a pair of microactuator elements. The flexure assembly also includes a tongue of the gimbal portion on which the slider is mounted. The tongue includes a dimple point which represents the center of the tongue. The flexure assembly also includes a pair of first supporting portions and a pair of second supporting portions of the gimbal portion. A pair of end portions are individually secured to the tongue and the first supporting portions and the pair of second supporting portions. The flexure assembly also includes a conductive circuit portion unsupported between a first stationary part and the pair of end portions.

A microactuator for a suspension is described. The microactuator includes a multi-layer PZT device having a first face and an opposite second face. Each layer of the multi-layer PZT device is configured to operate in its d15 mode when actuated by an actuation voltage. The layers are configured as a stack such that each layer is configured to act in the same direction when actuated such that the first face moves in shear relative to the second face.

A gimbal assembly includes a flex circuit with a first end extending along a loadbeam and second end having bond pads configured to be electrically coupled to a slider. The gimbal assembly includes a metallic layer with a fixed portion fixably attached to the loadbeam and a movable portion fixably attachable to the slider. The movable portion has at least one extension arm coupled to and providing support to the second end of the flex circuit. First and second linear actuators are coupled between the fixed portion and the movable portion. The first and second linear actuators cause a rotation of the slider in response to an electric signal.

Various embodiments concern a method of attaching a microactuator to a flexure, depositing a wet mass of structural adhesive on the flexure, mounting the microactuator on the wet mass of structural adhesive, partially curing the mass of structural adhesive through a first application of curing energy, and depositing a mass of conductive adhesive on the flexure. The mass of conductive adhesive is deposited in contact with the mass of structural adhesive. The state of partial curing of the structural adhesive prevents the conductive adhesive from wicking between the flexure and the underside of the microactuator and displacing the structural adhesive which may otherwise result in shorting to a stainless steel layer of the flexure. The method further comprises fully curing the mass of structural adhesive and the conductive adhesive through a second application of curing energy.

A gimbal assembly of a single or dual stage actuator is provided with gold at a tongue/dimple interface where a dimple of a supporting loadbeam contacts a tongue on the gimbal assembly. Using gold at the tongue/dimple interface greatly reduces the amount of wear particles formed during assembly and operation of the microactuator. The tongue may include a gold coating on the tongue at the tongue/dimple interface, or the tongue may have a hole etched in a stainless steel layer at the tongue/dimple interface to expose a gold layer disposed below the stainless steel layer. The tongue portion of the tongue/dimple interface may also be formed from a gold-coated copper pad with a polymer coating over the gold.

A microactuator for a dual stage actuated suspension for a hard disk drive is constructed as a longitudinal stack of piezoelectric (PZT) elements acting in the d33 mode, expanding or contracting longitudinally when an electric field is applied across them in the longitudinal direction. The microactuator has interlaced electrode fingers that separate and define the individual PZT elements, and apply the electric field. A stiff constraint layer having a high Young's modulus is affixed to the microactuator on the side opposite the suspension to which the microactuator is bonded. The constraint layer may be a layer of substantially inactive PZT material that is formed integrally with the PZT elements but without electrodes in the inactive PZT layer. The presence of the stiff constraint layer increases the effective stroke length of the microactuator.

A multi-layer piezoelectric microactuator assembly has at least one poled and active piezoelectric layer and one poled but inactive piezoelectric layer. The poled but inactive layer acts as a constraining layer in resisting expansion or contract of the first piezoelectric layer thereby reducing or eliminating bending of the assembly as installed in an environment, thereby increasing the effective stroke length of the assembly. Poling only a single layer would induce stresses into the device; hence, polling both piezoelectric layers even though only one layer will be active in use reduces stresses in the device and therefore increases reliability.

The present invention provides a method of surely detecting a crack in piezoelectric elements regardless of size of the crack. The method includes applying voltage to a first piezoelectric element of a pair of piezoelectric elements to cause deformation in the first piezoelectric element, forcibly deforming a second piezoelectric element of the pair of the piezoelectric elements to generate voltage from the second piezoelectric element according to the deformation of the first piezoelectric element, finding a transfer function of the pair of the piezoelectric elements based on values of the applied voltage and the generated voltage, and detecting presence or absence of a crack in the pair of the piezoelectric elements based on an objective value obtained from the found transfer function.