Disk Drive Suspension Piezoelectric Element Height Control
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Solution Overview
Problem
The existing methods for manufacturing disk drive suspensions with piezoelectric elements face challenges in stabilizing the position and height of these elements, leading to inconsistent performance due to adhesive viscosity issues and movement before curing.
Innovation Solution
A method involving the application of adhesive to an actuator mounting portion, increasing its viscosity with light, detecting the height of the piezoelectric element, and adjusting the light irradiation conditions to stabilize the element's position and height, followed by heating for curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive is applied to the actuator mounting portion and the piezoelectric element is placed on it, then the piezoelectric element can be fixed to the suspension, but the piezoelectric element may be unintentionally moved before the adhesive is cured
Solution Approach 1:
The adhesive is preliminarily cured by light irradiation before the piezoelectric element is placed on the actuator mounting portion. This preliminary curing action increases the adhesive viscosity and provides preliminary fixing strength, preventing the piezoelectric element from being unintentionally moved during the placement process while still allowing for position adjustment.
Solution Approach 2:
The adhesive undergoes a dynamic change in viscosity through light irradiation. Initially, the adhesive has low viscosity for easy application and positioning. After light irradiation, the viscosity increases to prevent movement. The system transitions from a state allowing movement to a state preventing movement, resolving the contradiction between fixing reliability and position precision.
2Productivity
If high temperature gas is sprayed by a heater to temporarily cure the adhesive, then the adhesive curing speed is improved, but the piezoelectric element may be moved due to surface tension, vibration, or unstable adhesive viscosity
Solution Approach 1:
The thermal curing method (using high temperature gas from a heater) is replaced with light irradiation curing. The light irradiation device emits light to the adhesive, causing photopolymerization and rapid viscosity increase without the thermal effects that cause movement. This substitution eliminates the harmful effects of heat while maintaining fast curing speed.
Solution Approach 2:
The curing method changes from thermal parameter control (temperature) to optical parameter control (light intensity and wavelength). By changing the curing parameter from heat to light, the adhesive cures rapidly without the side effects of thermal expansion, convection, and surface tension changes that cause element movement.
3Reliability
If the piezoelectric element height is varied, then the resonance characteristic of sway mode and yaw mode is affected, but controlling the height precisely is difficult with conventional methods
Solution Approach 1:
A feedback control system is implemented where the height of the piezoelectric element is measured after placement, and based on the measurement result, the light irradiation conditions (irradiation time, illuminance, or quantity of light) are adjusted to control the adhesive viscosity and consequently the element height. This closed-loop feedback ensures precise height control for consistent resonance characteristics.
Solution Approach 2:
The manufacturing process uses periodic light irradiation with controlled duration and intensity. By adjusting the irradiation time and illuminance in a periodic manner, the adhesive viscosity is precisely controlled to achieve the desired element height and maintain consistent resonance characteristics across production batches.
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 effectively stabilizes the position and height of the piezoelectric elements, ensuring consistent performance and resonance characteristics of the disk drive suspension.
Implementation Method 1
increasing viscosity of the adhesive by emitting light to the adhesive applied to the actuator mounting portion
Implementation Method 2
fixing the piezoelectric element to the actuator mounting portion by heating the actuator mounting portion on which the piezoelectric element is arranged and curing the adhesive
Data Source
AI summary
A method of manufacturing a disk drive suspension includes applying an adhesive to an actuator mounting portion, increasing viscosity of the adhesive by emitting light to the adhesive applied to the actuator mounting portion, arranging the piezoelectric element on the adhesive having the increased viscosity, detecting a height of the piezoelectric element arranged on the actuator mounting portion, and correcting an irradiation condition of the light in accordance with the detected height of the piezoelectric element.