Aluminum Alloy Base Plate for Thin HDD Impact Resistance
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Solution Overview
Problem
Hard disk drives (HDDs) face challenges in achieving high impact resistance due to the thinning of magnetic disks, which reduces their rigidity and makes them more susceptible to deformation and damage, despite efforts to incorporate materials like silicon into aluminum alloy substrates for improved rigidity.
Innovation Solution
A thin substrate built-in hard disk drive with a base plate made of an aluminum alloy that has a specific metallographic structure, featuring a perimeter of second phase particles with a longest diameter of 10 μm or more at 3 mm/mm² or more and no particles with a longest diameter of 500 μm or more per mm², which enhances impact resistance by absorbing vibration energy and preventing crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the magnetic disk is thinned to increase disk density, then the disk capacity increases, but the rigidity and impact resistance decrease
Solution Approach 1:
The base plate employs non-uniform local composition with specific aluminum alloy ratios (Si: 0.03-0.15 mass%, Fe: 0.01-0.05 mass%, Mn: 0.02-0.10 mass%) concentrated in critical impact zones. This local quality enhancement provides targeted rigidity support where needed while maintaining overall thin disk structure for high density storage.
Solution Approach 2:
The base plate utilizes a composite aluminum alloy material system combining multiple elements (Al-Si-Fe-Mn) to achieve synergistic effects. The composite structure provides both the thinness required for high disk density and the enhanced mechanical properties needed for impact resistance, resolving the contradiction between thinning and strength.
2Strength
If silicon content is increased to improve rigidity, then impact resistance improves, but manufacturability deteriorates
Solution Approach 1:
The invention optimizes the silicon content parameter within a specific range (0.03-0.15 mass%) rather than using excessive amounts. This parameter change achieves the necessary rigidity improvement while maintaining manufacturability, avoiding the harmful effects of high silicon content such as poor casting properties and manufacturing difficulties.
Solution Approach 2:
Instead of uniformly distributing high silicon content throughout the base plate, the invention applies localized enhancement with controlled silicon concentration in specific regions. This local quality approach provides sufficient rigidity where needed while keeping overall silicon content low enough to maintain ease of manufacture.
3Reliability
If the base plate structure is optimized for impact resistance, then magnetic disk protection improves, but device complexity increases
Solution Approach 1:
The invention achieves impact resistance optimization through parameter changes in the aluminum alloy composition (Si: 0.03-0.15 mass%, Fe: 0.01-0.05 mass%, Mn: 0.02-0.10 mass%) rather than through complex structural designs. This approach improves reliability while maintaining simple base plate geometry, avoiding increased device complexity.
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 described configuration significantly improves the impact resistance of the magnetic disk by reducing deformation and preventing helium leakage, making it suitable for high-capacity HDDs with increased disk density.
Implementation Method 1
the base plate has a metallographic structure in which a perimeter of a second phase particle having a longest diameter of 10 μm or more is 3 mm/mm2 or more, and the number of second phase particles having a longest diameter of 500 μm or more is 0 particles/mm2... capable of improving impact resistance of the magnetic disk
Data Source
AI summary
An example thin substrate built-in hard disk drive includes a magnetic disk in a disk shape having a through-hole at the center, a spindle motor inserted into the through-hole of the magnetic disk and co-rotatably supporting the magnetic disk, and a base plate made of an aluminum alloy and supporting the spindle motor. The base plate has a metallographic structure in which a perimeter of a second phase particle having a longest diameter of 10 μm or more is 3 mm/mm2 or more, and the number of second phase particles having a longest diameter of 500 μm or more is 0 particles/mm2.