Laminated Headlift Structure for Disk Drive Resonance Control
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Solution Overview
Problem
Current disk drive head suspensions face challenges in maintaining precise positioning due to resonance frequencies, which cause bending and twisting, leading to off-track motion, and existing headlift structures do not adequately address these issues while being efficiently manufacturable.
Innovation Solution
A headlift is designed using a laminated sheet of material with stiff layers and an etch stop layer, featuring a support region, tab, and offset region, manufactured through photolithography and etching processes, to enhance stiffness and minimize resonance impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a traditional headlift structure is used, then manufacturing is simple, but resonance characteristics are poor and positioning accuracy deteriorates
Solution Approach 1:
The headlift structure uses a laminated composite of multiple layers including a first layer, second layer, and etch stop layer. This composite structure provides enhanced stiffness and improved resonance characteristics while maintaining manufacturability through standard lamination and etching processes.
Solution Approach 2:
The headlift is divided into distinct functional regions including a support region, tab, and offset region. Each region is formed from specific layers of the laminate, allowing optimized performance in each area while maintaining overall structural integrity and manufacturability.
2Speed
If the suspension is driven at high rates of speed, then performance is improved, but resonance frequencies cause bending and twisting leading to off-track motion
Solution Approach 1:
The headlift structure modifies physical parameters including layer thicknesses, material properties, and geometric dimensions to shift resonance frequencies away from operational drive rates. This allows high-speed operation while minimizing resonance-induced positioning errors.
Solution Approach 2:
The laminated composite structure with multiple layers provides enhanced stiffness and damping characteristics that reduce bending and twisting motions at resonant frequencies, enabling high-speed operation with maintained positioning accuracy.
3Strength
If the headlift is made stiffer, then structural integrity is improved, but detrimental impact on resonance characteristics may increase
Solution Approach 1:
The multi-layer laminated structure provides optimized stiffness characteristics where the composite action of different layers delivers appropriate rigidity while the distributed mass and damping properties improve resonance characteristics compared to a single solid structure.
Solution Approach 2:
Different regions of the headlift use different layer configurations - the support region uses all layers for maximum stiffness, while the tab may use only specific layers to reduce mass and adjust resonance characteristics locally.
4Speed
If mass is reduced to improve sway frequency, then resonance characteristics improve, but manufacturing complexity increases
Solution Approach 1:
The headlift is segmented into multiple thin layers that can be selectively etched and configured. This segmentation allows precise mass distribution optimization to improve sway frequency while using standard multi-layer manufacturing processes.
Data Source
AI summary
A head suspension load beam including a beam region and a headlift formed by etching from a laminated sheet of material having first and second stainless steel layers separated by a polyimide layer. The beam region includes a base portion formed from the first stainless steel layer and a stiffener portion formed from the second stainless steel layer. The headlift extends from the beam region and includes an offset region and a concave tab. The offset region is formed from the first and second stainless steel layers and the polyimide layer. The tab extends from the offset region and is formed from only the second stainless steel layer.