HDD Base Member Vacuum Impregnation Sealing Casting Cavity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing techniques for sealing casting cavities in hard disk drive base members are inadequate, particularly when the cavity opening is small, leading to incomplete impregnation and potential gas buildup, which can cause electrodeposition coating film breakage and dust discharge into the device, resulting in read/write errors and gas leakage.
Innovation Solution
A base member with a machined portion and an impregnating agent filled into the casting cavity, followed by a coating film, using vacuum pressure impregnation to ensure the cavity is sealed and prevent gas buildup, employing resins like epoxy or acrylic to fill the cavity and cover inclusions, thereby suppressing dust discharge and gas leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrodeposition coating is used to seal the casting cavity, then the surface of the base member is covered to prevent dust, but the coating material does not sufficiently impregnate into small casting cavities (opening ≤ 20 μm), leading to incomplete sealing and potential dust discharge
Solution Approach 1:
The patent applies preliminary action by performing vacuum pressure impregnation with sealing resin before the electrodeposition coating process. This preliminary impregnation fills the casting cavity with sealing resin that can penetrate deep into small openings (≤ 20 μm) under vacuum pressure, ensuring complete sealing before the protective coating is applied. This resolves the contradiction by achieving thorough impregnation that electrodeposition alone cannot provide.
Solution Approach 2:
The patent uses composite materials by combining sealing resin (epoxy or acrylic-based) with the electrodeposition coating material. The sealing resin provides deep cavity penetration and sealing, while the electrodeposition coating provides surface protection and dust prevention. This composite approach addresses the limitation of electrodeposition alone by adding a material that can effectively seal small cavities.
2Ease of manufacture
If the casting cavity is left open or improperly sealed, then the manufacturing process is simpler, but gas components from moisture-inclusion reactions can build up pressure and destroy the coating film, causing dust discharge and read/write errors
Solution Approach 1:
The vacuum pressure impregnation process is performed as a preliminary step before electrodeposition coating, ensuring that the casting cavity is completely filled with sealing resin and any inclusions are covered before the coating is applied. This preliminary sealing action prevents gas buildup that would otherwise destroy the coating film, maintaining reliability without significantly complicating the manufacturing process.
Solution Approach 2:
The patent changes the physical parameters of the sealing process by using vacuum pressure impregnation, which alters the pressure and atmospheric conditions during resin infiltration. This parameter change enables the sealing resin to penetrate deep into small cavities and completely fill them, preventing gas buildup and protecting the coating film integrity.
3Measurement precision
If the disk facing surface is machined to adjust the distance from the hard disk, then rotational accuracy is improved, but the machining may expose the casting cavity at the surface, creating a source of dust and gas leakage
Solution Approach 1:
The patent applies preliminary action by performing vacuum pressure impregnation with sealing resin immediately after machining the disk facing surface, while the casting cavity is still exposed. This ensures that the newly exposed cavity is sealed before it can become a source of dust or gas leakage, maintaining both the improved rotational accuracy from machining and preventing harmful effects from exposed cavities.
Solution Approach 2:
The patent applies local quality by selectively sealing only the casting cavity areas that are exposed after machining, rather than treating the entire surface. The sealing resin is impregnated specifically into the exposed cavity regions, providing localized sealing that maintains the precision of the machined surface while preventing dust and gas leakage from the cavity.
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 maintains the sealed condition of the casting cavity, reduces the breakage of the coating film, and minimizes dust and gas leakage into the device, significantly reducing defects such as read/write errors and helium gas leakage.
Implementation Method 1
using vacuum pressure impregnation to ensure the cavity is sealed and prevent gas buildup
Implementation Method 2
an electrodeposition coating film is formed so as to close the opening portion of the casting cavity by a coating solution having viscosity
Data Source
AI summary
A base member serving as a part of a housing of a hard disk drive device. The base member includes a base body being a cast product, a machined surface obtained by machining a part of the base body at a side of an interior of the housing, an impregnating agent filled into a casting cavity exposed at the machined surface, and a coating film covering a surface including the machined surface of the base body.