Magnetic Disk Substrate Rigidity Tuning for Low-Particle Vibration
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Solution Overview
Problem
The increase in magnetic disk diameter and reduction in thickness lead to increased vibration and particle formation due to external impacts, which can damage the magnetic disk and hinder data storage capacity.
Innovation Solution
A substrate with a diameter of 85-100 mm and thickness of 0.3-0.5 mm, made of high Young's modulus glass or aluminum alloy, with a chamfered edge and specific material properties to minimize vibration and particle formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the diameter of the substrate is increased and the thickness is reduced, then the storage capacity is improved by fitting more disks, but the rigidity decreases and vibration increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the thickness parameter (0.3-0.5mm) and material properties (Young's modulus 90-120 GPa) to achieve the optimal balance between rigidity and storage capacity. This allows maximizing the number of disks while maintaining sufficient vibration resistance.
Solution Approach 2:
The patent uses composite material strategies by selecting glass substrates with specific Young's modulus ranges (90-120 GPa) that combine high rigidity with the required thinness. This material selection enables the substrate to resist vibration despite reduced thickness.
2Quantity of substance
If the diameter of the substrate is increased and the thickness is reduced, then the storage capacity is improved, but the vibration amplitude increases causing particle formation
Solution Approach 1:
The patent controls material parameters (Young's modulus 90-120 GPa) and geometric parameters (thickness 0.3-0.5mm) to limit vibration amplitude. This parameter optimization prevents particles from forming during impact while maintaining high storage capacity through increased disk density.
Solution Approach 2:
The patent applies beforehand cushioning by designing the substrate with optimized rigidity properties that prevent excessive vibration during impact before particles can form. The controlled Young's modulus and thickness create a cushioning effect that absorbs impact energy without generating harmful particles.
3Productivity
If the thickness of the substrate is reduced, then the number of disks per HDD is increased, but the vibration settling time increases
Solution Approach 1:
The patent optimizes the thickness parameter (0.3-0.5mm) and material properties (Young's modulus 90-120 GPa, Q-value 1500 or less) to achieve the best balance between fitting more disks and ensuring vibration settles quickly enough. The controlled material damping properties are critical for reducing settling time.
Solution Approach 2:
The patent applies local quality by selecting materials with specific damping characteristics (Q-value 1500 or less) that are optimized for vibration attenuation. This local material property selection ensures that even thin substrates quickly dissipate vibration energy.
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
The solution effectively suppresses particle formation and enhances the durability of magnetic disks, allowing for increased storage capacity and reduced failure rates due to external impacts.
Implementation Method 1
a material of the substrate has a Young's modulus E of 90 GPa or more
Implementation Method 2
a material of the substrate has a Q-value of 1500 or less under conditions of 3000 Hz and room temperature
Data Source
AI summary
A substrate for a magnetic disk has a disk shape. The substrate has a diameter D of 85 mm or more and 100 mm or less, and a thickness T of 0.3 mm or more and 0.5 mm or less. Regarding a Young's modulus E and the thickness T of the substrate, a value of E·T3 is 3 to 18 (GPa·mm3). A material of the substrate has a Q-value of 1500 or less under conditions of 3000 Hz and room temperature.