Wireless Disk Drive Flexure Curved Trace Geometry
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Solution Overview
Problem
In wireless disk drive suspensions, precise pitch and roll adjustments are challenging due to differing responses of stainless steel and polyimide layers, leading to strain energy build-up and springback losses, which complicate the adjustment process and compromise precision.
Innovation Solution
A wireless disk drive suspension design featuring a beam portion and flexure frame with a metal layer and a laminate portion of trace conductors and insulative plastic film, where the laminate portion is reversely deflected to absorb tension and compression forces, introducing curvilinear shapes that offset material differences and reduce springback, allowing closer approach to the disk drive hub.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pitch and roll adjustments are made to the flexure, then the slider is placed in its designed disposition, but strain energy builds up in the traces causing springback and compromising adjustment precision
Solution Approach 1:
The patent introduces curvilinear trace geometry with curves and serpentine patterns in the laminate portion. These curved paths allow the traces to accommodate strain energy through geometric flexibility rather than linear tension, enabling adjustments to be made without building up excessive strain that would cause springback. The curves act as strain relief features that maintain trace integrity while allowing precision adjustment.
Solution Approach 2:
The patent changes the geometric parameters of the trace paths from straight lines to curved configurations. By modifying the trace geometry to include curves, serpentine sections, and varying path lengths, the system can absorb strain energy through the curved geometry rather than through linear elastic deformation. This parameter change allows the traces to flex without compromising the precision of pitch and roll adjustments.
2Quantity of substance
If the flexure uses straight path minimum material approach, then material usage is minimized, but strain energy accumulates during adjustments causing springback
Solution Approach 1:
The patent replaces straight trace paths with curved and serpentine geometries in the laminate portion. These curved paths provide strain relief by allowing the traces to flex and accommodate deformation during pitch and roll adjustments. The curvilinear geometry distributes strain energy along the curved path rather than concentrating it, preventing springback while maintaining material efficiency.
Solution Approach 2:
The patent adds geometric complexity in the planar dimension by introducing curves, serpentine patterns, and varying trace path lengths. This two-dimensional geometric variation allows the traces to accommodate strain through in-plane deformation rather than requiring additional material thickness or volume. The traces flex within the plane of the laminate, providing strain relief without increasing material quantity.
3Reliability
If the laminate portion is made longer than the flexure frame length, then strain forces are absorbed through reverse deflection, but the flexure width increases
Solution Approach 1:
The patent uses curvilinear trace geometry where the laminate portion extends beyond the flexure frame length in a curved or serpentine pattern. The curves allow the traces to deflect in reverse direction during pitch and roll adjustments, absorbing strain energy through the curved path. The serpentine configuration provides multiple deflection points that distribute strain relief along the extended laminate length.
Solution Approach 2:
The patent segments the laminate portion into distinct functional zones: sections that extend beyond the flexure frame for strain absorption, intermediate sections for electrical connectivity, and sections integrated with the flexure frame for structural support. This segmentation allows different portions of the laminate to perform different functions, with the extended portions specifically dedicated to strain energy management through reverse deflection.
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
This design minimizes strain energy build-up and springback losses during pitch and roll adjustments, maintaining precision and enabling a closer approach to the disk drive hub for increased capacity.
Implementation Method 1
the laminate portion of the flexure having a greater length than the flexure frame given length to reversely deflect along its greater length against accumulation of tension or compression forces during the pitch and roll adjustment and adjustment compromising springback
Data Source
AI summary
A wireless disk drive suspension and method of manufacture in which curvilinear deflections of the plastic film and conductive traces relative to the flexure metal layer provide for containment of the strains accompanying pitch and roll adjustment of the flexure and allow adjustment free of adjusting difficulties and spring back compromise of the adjustment. The curvilinear deflection of the laminate toward the flexure central longitudinal axis and an accompanying bringing in of the flexure frame struts provides a less wide flexure that can more closely approach a disk drive hub for greater capacity in a disk drive.