Hard Disk Drive Cover With Differential Surface Roughness
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Solution Overview
Problem
Hard disk drive covers with textured surfaces fail to meet cleanliness requirements due to their roughness, which leads to particle shedding and reliability issues, while also not adequately addressing visual appearance concerns, and existing cost-effective solutions like passivated stainless steel do not meet cleanliness standards.
Innovation Solution
A hard disk drive cover with a smooth inner surface and a textured outer surface is manufactured using differential surface finishing methods, where the smooth surface faces the base assembly for enhanced cleanliness and the textured surface provides visual appeal, with the textured surface being at least 0.127 μm rougher than the smooth surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a textured surface finish is applied to both the outer and inner surfaces of the cover, then the visual appearance is improved by preventing and hiding scratches and blemishes, but the cleanliness is worsened due to increased particle shedding and difficulty in cleaning
Solution Approach 1:
The patent applies different surface qualities to different locations of the cover. The outer surface maintains a textured finish (Ra 0.4-1.0 μm) for visual appearance, while the inner surface uses a smooth finish (Ra 0.05-0.25 μm) for cleanliness. This local differentiation resolves the contradiction by allowing each surface to optimize for its specific function.
2Object-generated harmful factors
If a smooth surface finish is applied to the inner surface of the cover, then the cleanliness is improved by reducing particle shedding and easing cleaning, but the visual appearance is worsened by failing to hide scratches and blemishes
Solution Approach 1:
The patent applies different surface qualities to different locations of the cover. The outer surface maintains a textured finish (Ra 0.4-1.0 μm) for visual appearance, while the inner surface uses a smooth finish (Ra 0.05-0.25 μm) for cleanliness. This local differentiation resolves the contradiction by allowing each surface to optimize for its specific function.
3Object-generated harmful factors
If EN plating is applied to the cover, then the cleanliness is improved by creating a continuous tightly bonded coating that reduces scratches, but the cost is worsened significantly
Solution Approach 1:
The patent changes the surface roughness parameter differently for the inner and outer surfaces of the same material (passivated stainless steel). By controlling the Ra value within specific ranges for each surface, the patent achieves cleanliness comparable to EN plating while maintaining the cost-effectiveness of stainless steel.
Data Source
AI summary
A hard disk drive cover with a smooth bottom (inner) surface and a textured outer surface is provided for covering a hard disk drive base assembly. A method of manufacturing the hard disk includes providing a metal material. The metal material is worked into a metal strip having a textured surface and an opposing smooth surface. A hard disk drive cover is stamped from the worked metal strip with the smooth surface being the inner surface of the stamped cover. The smooth inner surface of the hard disk drive advantageously enhances cleanliness within the base assembly. The smooth surface finish on the inner surface also advantageously enhances shear strength of a bond between a gasket and the inner surface.