Disk Drive Flexure Thickness Reduction via Side-Wall Wiring
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Solution Overview
Problem
The challenge is to further miniaturize the head gimbal assembly of disk drives to achieve higher precision in positioning the slider on the disk recording surface, while also addressing the issue of suspension thickness to prevent contact between adjacent suspensions in multi-disk configurations.
Innovation Solution
A flexure for a disk drive suspension is designed with a metal base and a wiring portion that includes a base insulating layer, a conductor layer, and a cover insulating layer. This configuration allows for a thinner flexure by ensuring that the conductor layer does not overlap with the metal base, and the insulating layers are in contact with the side surfaces of the metal base, thereby reducing the overall thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the suspension is thinned to prevent contact between adjacent suspensions in multi-disk configurations, then the risk of contact between suspensions is reduced, but the load beam thickness cannot be reduced further as it affects spring load and suspension resonance
Solution Approach 1:
The suspension is divided into two separate components: a load beam and a flexure. The load beam maintains its traditional thickness to preserve spring load and resonance characteristics, while the flexure is made thin by using a layered structure with insulating layers and conductor traces. This segmentation allows each component to be optimized independently for its specific function.
Solution Approach 2:
The flexure is constructed as a composite structure with multiple layers including base insulating layers, conductor layers, and cover insulating layers. This composite material approach allows the flexure to achieve the required mechanical flexibility and electrical functionality while maintaining a thin profile that enables closer disk spacing.
2Measurement precision
If the head gimbal assembly is miniaturized to achieve higher precision positioning, then positioning precision is improved, but the suspension must be thinned which increases the risk of contact between adjacent suspensions
Solution Approach 1:
By segmenting the suspension into load beam and flexure components, the system can achieve miniaturization of the head gimbal assembly while maintaining adequate suspension thickness through the load beam. The thin flexure allows compact design without compromising overall suspension integrity.
3Ease of manufacture
If the conductor layer overlaps with the metal base to simplify manufacturing, then manufacturing complexity is reduced, but the flexure thickness increases which may cause contact between adjacent suspensions
Solution Approach 1:
Instead of positioning the conductor layer directly on top of the metal base (vertical stacking), the conductor layer is routed between the side surfaces of the metal base, utilizing the lateral space. This dimensional reorganization reduces the vertical thickness of the flexure while maintaining electrical connectivity and structural integrity.
Data Source
AI summary
A flexure of a disk drive suspension includes a metal base, and a wiring portion provided along the metal base. The wiring portion includes a base insulating layer, a conductor layer overlapping with the base insulating layer, and a cover insulating layer overlapping with the conductor layer, and the metal base includes a pair of first portions having side surfaces opposed to each other and a second portion overlapping with the conductor layer and connected to the pair of first portions. At least one of the base insulating layer and the cover insulating layer is in contact with the side surfaces between the pair of first portions, and a thickness of the second portion is smaller than a thickness of the first portions.