Magnetic Recording Head Clearance Adjustment via Thermal Deformation
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Solution Overview
Problem
The increasing demand for high-density disk storage systems requires ultra-low flying heights for transducer heads, but manufacturing variations and temperature limitations restrict achievable passive fly heights, leading to reduced factory yields as heads with high passive fly heights are often unusable.
Innovation Solution
A heating source is used to permanently deform the magnetic recording head, allowing for local adjustment of the transducer region to achieve a desirable passive fly height, with controllable energy application to adjust the head's shape and clearance, either on or off the disk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manufacturing processes are used to produce magnetic recording heads, then heads are manufactured with certain passive fly heights, but part to part variation causes distribution in fly height leading to reduced factory yields
Solution Approach 1:
The patent applies preliminary action by performing fly height adjustment before the head is installed in the disk drive. The heating element is activated during manufacturing to deform the head body and adjust passive fly height to the target range, ensuring that only heads meeting specifications proceed to assembly, thereby improving factory yield without requiring post-assembly adjustments or scrapping non-conforming heads.
Solution Approach 2:
The patent employs parameter changes by utilizing thermal energy to change the physical state of the head body material. The heating element raises the temperature of the head body to a level where the material becomes deformable, allowing adjustment of the passive fly height parameter. After cooling, the deformed shape is maintained, providing a permanent adjustment to the fly height parameter for each head.
2Manufacturing precision
If heating actuators are activated to modify the head to achieve desired operational clearance, then operational clearance is adjusted, but high temperatures generated degrade head reliability
Solution Approach 1:
The patent applies local quality by concentrating the heating action only in the head body region adjacent to the transducer, rather than heating the entire head assembly. The heating element is positioned to deliver thermal energy locally to the specific area that needs deformation, minimizing the volume of material exposed to high temperatures and reducing thermal stress on temperature-sensitive components, thereby maintaining head reliability while achieving the desired operational clearance adjustment.
Solution Approach 2:
The patent performs the thermal deformation action during the manufacturing process before the head is installed in the disk drive. By completing the fly height adjustment preliminarily, the heating actuator only needs to operate once during fabrication, rather than requiring repeated high-temperature operations during field use, thereby minimizing cumulative thermal exposure and preserving head reliability.
3Quantity of substance
If passive fly height is reduced to achieve high-density storage, then data density increases, but manufacturing variations make it difficult to achieve consistent ultra-low flying heights
Solution Approach 1:
The patent implements preliminary adjustment of passive fly height during the head manufacturing process. By activating the heating element to deform the head body and achieve the target fly height before assembly, the system can compensate for manufacturing variations and ensure that each head meets the ultra-low flying height specification required for high-density storage, rather than relying solely on precision manufacturing tolerances.
Solution Approach 2:
The patent introduces dynamics by transforming the static head body into a temporarily deformable state through heating. The head body material transitions from a rigid state during manufacturing to a softer, more compliant state when heated, allowing adjustment of the passive fly height. After cooling, the head returns to its rigid state with the new, adjusted geometry, enabling dynamic adjustment capability that was not possible in the original static manufacturing process.
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 method enables heads with high initial passive fly heights to be adjusted to a more desirable range, ensuring optimal operating temperatures and reducing scrap rates, thereby improving factory yields and maintaining high data density capabilities.
Implementation Method 1
applying a first quantity of energy to the at least one heating element to permanently deform the head and change the distance between the top surface of the disk and a bottom surface of the head
Data Source
AI summary
A method of controlling clearance in a disk drive, including the steps of: mounting a recording head having at least one heating element at a first distance from a top surface of the disk; measuring a first passive fly height between the top surface of the disk and a bottom surface of the head; applying a first quantity of energy to the heating element(s) to permanently deform the head and change the distance between the top surface of the disk and a bottom surface of the head to a second passive fly height that is less than the first passive fly height; and applying a second quantity of energy to the heating element(s) to temporarily deform the head and change the distance between the top surface of the disk and a bottom surface of the head to an operational clearance distance that is less than the second passive fly height.