PZT Actuator Repolarization After High-Temp Soldering
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Solution Overview
Problem
Magnetic storage devices face challenges in securely mounting actuators to flexures without degrading their performance, particularly in maintaining the capacitance of piezo-electric actuators used in these devices.
Innovation Solution
The solution involves a magnetic storage device design with a flexure having a fixed and hinge portion, where the actuator system is coupled to both, and repolarization enhancing features like buckles or U-shaped bends are used to maximize the capacitance of lead zirconate titanate (PZT) piezo-electric actuators by repolarizing them after mounting with solder pads having a melting temperature higher than the depolarization temperature, and then constraining them with encapsulation material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If solder pads with melting temperature higher than depolarization temperature are used to mount the actuator, then secure mounting is achieved, but the piezo-electric actuator depolarizes and loses capacitance
Solution Approach 1:
The patent applies preliminary action by performing the repolarization process after the soldering operation. The actuator is mounted first with high-temperature solder pads, then subsequently repolarized to restore capacitance. This sequence ensures secure mounting while recovering the electrical property that would otherwise be lost during the high-temperature soldering process.
Solution Approach 2:
The patent applies discarding and recovering by accepting the temporary loss of polarization during soldering, then recovering the capacitance through a subsequent repolarization step. The high-temperature soldering process intentionally allows depolarization, which is then corrected by applying an electric field to realign the piezo-electric domains, effectively recovering the lost electrical property.
2Stability of the object's composition
If the actuator is securely mounted to the flexure, then mechanical stability is improved, but the actuator performance degrades due to depolarization
Solution Approach 1:
The patent performs the repolarization operation after mechanical mounting is complete. The actuator is first securely attached to the flexure using solder pads, establishing mechanical stability. Then, the repolarization process is applied to restore the piezo-electric properties, ensuring both mechanical stability and electrical performance are achieved in sequence.
3Ease of manufacture
If high temperature soldering process is used for mounting, then secure attachment is achieved, but the piezo-electric material loses its polarization
Solution Approach 1:
The patent employs discarding and recovering by accepting the loss of polarization during the high-temperature soldering process, then recovering the capacitance through a subsequent repolarization step. The manufacturing process intentionally allows the piezo-electric material to depolarize during soldering, then restores it by applying an electric field to realign the domains.
Solution Approach 2:
The patent applies preliminary action by completing the mechanical mounting operation first, then performing the repolarization as a subsequent step. This sequence allows the manufacturing process to proceed with standard high-temperature soldering without concern for polarization loss, as the repolarization step follows to restore the electrical property.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures the actuator's capacitance remains at its maximum possible value, enhancing the device's performance and reliability by preventing depolarization during the mounting process and promoting effective repolarization.
Implementation Method 1
repolarizing the PZT material after mounting with solder pads having a melting temperature higher than the depolarization temperature
Implementation Method 2
heating the solder pads up to at least a melting temperature of the solder pads
Implementation Method 3
an actuator system operable to sway the hinge portion relative to the fixed portion... comprising lead zirconate titanate (PZT) material
Data Source
AI summary
A magnetic storage device comprising a magnetic disk and a carriage arm rotatably movable relative to the magnetic disk. A suspension assembly of the magnetic storage device is coupled to the carriage arm and comprising a flexure. The magnetic storage device additionally comprises a slider comprising a read-write head. The flexure comprises a fixed portion co-movably fixed relative to the carriage arm and a hinge portion to which the slider is co-movably fixed. The hinge portion is swayable relative to the fixed portion. An actuator system of the magnetic storage device is coupled to the fixed portion of the flexure and the hinge portion of the flexure. The actuator system is operable to sway the hinge portion relative to the fixed portion. The magnetic storage device includes a repolarization enhancing feature adjacent the actuator system.