HGA Suspension Dimple Secondary Structure for Contact Point Restriction
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Solution Overview
Problem
The contact point of the suspension dimple in hard disk drives can change due to wear, leading to performance degradation in slider flyability as the head slider rotates about an undesirable axis instead of the intended dimple axis, affecting the orientation and positioning of the read-write head.
Innovation Solution
A secondary structure, such as a micro-dimple, ridge, or embedded material, is formed on the primary dimple to restrict the contact point and maintain the intended axis of rotation, preventing changes in the dimple contact point even as the surface becomes coarse and rough due to wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the suspension dimple surface is used as the contact point for slider rotation, then the slider can rotate about the dimple axis, but wear causes the contact point to change, leading to rotation about an undesirable axis and performance degradation
Solution Approach 1:
A secondary structure (micro-dimple, ridge, or embedded material) is formed on the primary dimple surface before the wear process begins. This preliminary structure is designed to be the first point of contact for the slider, ensuring that rotation occurs about the intended dimple axis from the start. By pre-establishing this contact restriction mechanism, the patent prevents the contact point from migrating due to wear, thereby maintaining reliable slider flyability over the operational lifetime of the hard disk drive.
2Reliability
If a secondary structure is added to the primary dimple to restrict the contact point, then the axis of rotation is maintained, but the device complexity increases
Solution Approach 1:
Rather than modifying the entire dimple structure, the patent applies a secondary structure only at the specific location where contact with the slider occurs. This localized modification (a micro-dimple, ridge, or embedded material at the contact point) provides the necessary contact restriction while leaving the rest of the dimple structure simple and straightforward to manufacture. The local quality principle ensures that the complexity is minimized while achieving the reliability goal of maintaining stable rotation axis.
Data Source
AI summary
A head gimbal assembly (HGA) for a hard disk drive includes a primary dimple having a secondary structure protruding from the primary dimple, where a flexure is movably coupled with a load beam via the primary dimple, and where the secondary structure is configured to restrict the point of contact between the load beam and the flexure. Such an arrangement avoids any shift in the axis of rotation of the flexure, and the attached slider, due to any undesirable protrusion from the primary dimple which may arise in the manufacturing process. Examples of secondary structures include a micro-dimple, a ridge, and an embedded mass of material.