DLC Coated Dimple Contact Interface for Disk Drive Head Suspension
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Solution Overview
Problem
Magnetic hard disk drives experience fretting wear and corrosion at the dimple contact interface between the load beam and the laminated flexure, leading to undesirable stick, slip, and iron oxide particulate contamination due to prolonged relative pivoting motion.
Innovation Solution
A diamond-like carbon (DLC) coating is applied between the dimple of the load beam and the tongue of the laminated flexure to reduce wear and corrosion, with the coating thickness ranging from 3 nm to 50 nm and optionally adhered within an etched recession to prevent contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stainless-steel contact interface is used at the dimple contact location, then structural strength and durability are maintained, but fretting wear and corrosion occur due to prolonged relative pivoting motion
Solution Approach 1:
The patent applies a diamond-like carbon (DLC) coating on the stainless-steel dimple contact interface, creating a composite structure that combines the mechanical strength of stainless steel with the low-friction, wear-resistant properties of DLC material. This composite approach eliminates fretting wear and corrosion while maintaining structural integrity
Solution Approach 2:
The patent changes the surface properties of the contact interface by applying a DLC coating, which fundamentally alters the friction and wear characteristics. The coating thickness is controlled within a specific range (0.1 micrometer to 2.0 micrometers) to optimize performance while preventing stick-slip phenomena
2Reliability
If a thicker DLC coating is applied to reduce wear, then fretting wear and corrosion are reduced, but the coating may detach and cause contamination
Solution Approach 1:
The patent optimizes the DLC coating thickness within a specific range (0.1 micrometer to 2.0 micrometers). This parameter control ensures the coating is thick enough to provide wear protection and corrosion resistance, yet thin enough to maintain adhesion and prevent detachment that would cause contamination
Solution Approach 2:
The DLC coating is applied specifically to the dimple contact interface where wear occurs, rather than coating the entire component. This localized application provides wear protection exactly where needed while minimizing the risk of coating detachment and contamination
3Reliability
If the DLC coating thickness is increased beyond the specified range, then wear protection is improved, but stick and slip phenomena and coating detachment occur
Solution Approach 1:
The patent establishes and maintains the DLC coating thickness within the optimal range of 0.1 micrometer to 2.0 micrometers. This parameter control balances wear protection with operational smoothness, preventing both insufficient protection and excessive thickness that would cause stick-slip phenomena
Solution Approach 2:
The patent references industry standards and previous successful implementations to establish the optimal coating thickness range. This copied knowledge from established practices ensures the coating provides adequate wear protection without causing operational issues
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 DLC coating significantly reduces fretting wear and corrosion at the dimple contact interface, minimizing stick and slip phenomena and preventing iron oxide particulate contamination, thereby enhancing the reliability and longevity of the head gimbal assembly.
Implementation Method 1
The DLC coating significantly reduces fretting wear and corrosion at the dimple contact interface, minimizing stick and slip phenomena
Implementation Method 2
A diamond-like carbon (DLC) coating is applied between the dimple of the load beam and the tongue of the laminated flexure to reduce wear and corrosion
Data Source
AI summary
A suspension assembly for a head gimbal assembly of a disk drive includes a laminated flexure that includes a tongue for attachment of a read head. The suspension assembly includes a load beam that, in a first aspect of the present invention has a protruding dimple that contacts the tongue. In this aspect of the invention, a diamond-like carbon (DLC) coating is disposed between and contacting the dimple and the tongue. For example, the DLC may be disposed on the tongue at the location of contact with the load beam dimple. Alternatively, in a second aspect of the present invention, the tongue may have a protruding dimple that contacts the load beam. In this aspect of the invention, a DLC coating is disposed between and contacting the dimple and the load beam.