Segmented Wrap Around Shield for Magnetic Head Stress Reduction
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Solution Overview
Problem
Typical magnetic heads with wrap around shields experience stress-induced degradation during the lapping process, leading to loss of magnetic flux flow and local magnetic micro regions that can cause data erasure.
Innovation Solution
A magnetic head design featuring a wrap around shield with inner, middle, and second regions of varying cross-sectional heights, separated by transitional regions, and optionally divided by a nonmagnetic gap, to reduce stress and maintain magnetic flux flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If full film plating is used to form the wrap around shield, then the shield structure is complete and continuous, but stress-induced degradation occurs during lapping that degrades magnetic material properties
Solution Approach 1:
The wrap around shield is divided into multiple discrete magnetic material segments rather than using a continuous full film plating. Each segment is independently positioned and secured to the nonmagnetic shield substrate, allowing individual optimization of magnetic properties without stress-induced degradation from lapping processes affecting the entire continuous structure.
Solution Approach 2:
The shield assembly uses a composite structure combining discrete magnetic material segments with a nonmagnetic shield substrate. This composite approach allows the magnetic segments to maintain their magnetic properties while being supported by the nonmagnetic substrate, avoiding the stress issues that arise in fully plated continuous structures during lapping.
2Manufacturing precision
If lapping is performed on the plated wrap around shield, then the surface finish is improved, but stress is induced that degrades magnetic material properties
Solution Approach 1:
By segmenting the magnetic material into discrete pieces rather than using a continuous plated layer, the structure avoids the stress-induced degradation that occurs during lapping of continuous plated shields. The segmented structure can be finished without compromising the magnetic properties of individual segments.
Solution Approach 2:
Different regions of the shield assembly have different properties: discrete magnetic material segments in regions requiring magnetic flux conduction, and nonmagnetic shield substrate in other regions. This local differentiation allows surface finishing processes to be applied without degrading magnetic properties in the critical magnetic segments.
3Reliability
If the wrap around shield is made as a single continuous structure, then magnetic flux flow is maintained, but stress during lapping creates local magnetic micro regions that cause data erasure
Solution Approach 1:
The magnetic shield is segmented into multiple discrete magnetic material segments rather than using a single continuous structure. This segmentation prevents the formation of stress-induced local magnetic micro regions while maintaining effective magnetic flux conduction through the series of discrete segments positioned along the magnetic pole.
Solution Approach 2:
The shield assembly uses discrete magnetic material segments positioned at specific locations where magnetic flux conduction is needed, rather than a continuous structure throughout. This localized approach to magnetic material placement maintains flux conduction where required while eliminating the harmful local magnetic micro regions that form in continuous plated structures under stress.
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 design minimizes stress-induced degradation, maintaining the magnetic properties of the wrap around shield and preventing data erasure by optimizing the cross-sectional heights and transitional regions of the shield.
Implementation Method 1
the loss of the ability to conduct the magnetic flux flow
Implementation Method 2
the wrap around shield develops undesirable stress after lapping
Data Source
AI summary
According to one embodiment, a system comprises a magnetic pole having a media-facing end and a wrap around shield spaced from the magnetic pole, wherein the wrap around shield has a media-facing end positioned along three sides of the media-facing end of the magnetic pole and has inner, second, and middle regions separated by transitional regions. The inner region is closest to the media facing end of the magnetic pole, the second region is farthest from the media facing end of the magnetic pole, and the middle region is between the inner and second regions. A cross-sectional height of the inner region measured perpendicularly to the wrap around shield's media-facing end is less than a cross-sectional height of the second region, and a cross-sectional height of the middle region is greater than the cross-sectional height of the inner region and less than the cross-sectional height of the second region.