Thin Magnetic Disk Coating Balance for Slider Stability
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Solution Overview
Problem
Reducing the thickness of magnetic storage device disks introduces physical limitations that affect performance, leading to issues such as disk vibration and flatness deviations, which can cause the slider to deviate or hit portions of the disk.
Innovation Solution
The disk thickness is maintained by controlling the maximum thickness difference between coating layers, which is a function of the square of the disk thickness and the substrate's Young's modulus, ensuring minimal flatness deviation and rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the disk is reduced to maintain smaller HDD size, then the size of the HDD is reduced, but disk vibration and flatness deviation increase causing slider to deviate or hit the disk
Solution Approach 1:
The patent applies parameter changes by establishing a specific mathematical relationship between disk thickness and coating layer thickness difference. By controlling the thickness difference to be a function of the square of the disk thickness, the system maintains disk rigidity and flatness even as overall thickness is reduced, preventing slider deviation while achieving compact HDD size
Solution Approach 2:
The patent uses composite materials by combining the substrate with coating layers of specific thickness differences. This composite structure allows the disk to maintain mechanical strength and rigidity at reduced thicknesses, preventing vibration-induced slider contact while enabling smaller HDD form factor
2Length of moving object
If the thickness of the disk is reduced, then the disk is thinner, but the disk loses rigidity and flatness
Solution Approach 1:
The patent changes the parameter relationship by defining the coating layer thickness difference as a function of the square of the disk thickness. This mathematical relationship ensures that as disk thickness decreases, the thickness difference is controlled to maintain the necessary rigidity and flatness, preventing disk deformation
Solution Approach 2:
The patent applies local quality by concentrating the thickness difference control at the coating layers rather than the substrate. By locally adjusting the coating layer thickness difference, the system maintains overall disk rigidity while allowing the substrate to be thinner, achieving both compact size and structural integrity
Data Source
AI summary
A disk for a magnetic recording apparatus. The disk includes a substrate comprising a first surface and a second surface, wherein the substrate has a substrate thickness. The disk includes a first coating layer disposed over the first surface of the substrate, wherein the first coating layer has a first coating layer thickness. The disk includes a second coating layer disposed over the second surface of the substrate, wherein the second coating layer has a second coating layer thickness. The disk has a disk thickness, wherein the disk thickness includes the substrate thickness. The maximum thickness difference between the first coating layer thickness and the second coating layer thickness is a function of the square of the disk thickness.