Carrier Bridge CTE Matching for Slider Lapping Stability
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Solution Overview
Problem
Existing carrier technologies for lapping slider row bars in hard disk drives face challenges in maintaining structural support and thermal expansion compatibility, leading to issues like undue flexing and bowing during the lapping process.
Innovation Solution
A carrier with a bridge and bridge bending members, where the bridge length is greater than the slider row bar length, and the bridge material has a coefficient of thermal expansion ratio less than 1.6 compared to the row bar, providing enhanced structural support and thermal expansion matching to prevent bowing and ensure precise lapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a carrier is used to support slider row bars during lapping, then structural support is provided, but thermal expansion mismatch causes undue flexing and bowing
Solution Approach 1:
The patent changes the material parameter (coefficient of thermal expansion) of the bridge from conventional materials to a material with CTE between 3-15 ppm/°C, specifically matched to the slider row bar material. This parameter matching eliminates thermal expansion mismatch during lapping operations, preventing bowing and flexing while maintaining structural support.
Solution Approach 2:
The bridge is constructed from composite or specially formulated material that achieves the desired CTE range. This may involve using ceramic-matrix composites or metal matrix composites that can be engineered to have specific thermal expansion properties matching the slider row bar, thereby resolving the contradiction between structural support and dimensional stability.
2Stability of the object's composition
If the bridge length is increased to provide better support, then structural stability improves, but device complexity increases
Solution Approach 1:
Rather than increasing bridge length, the patent changes the material parameter (CTE) to achieve thermal expansion compatibility. This resolves the stability issue through material selection rather than geometric modification, avoiding increased device complexity while maintaining structural stability during lapping.
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 solution effectively prevents undue flexing and bowing of slider row bars, ensuring accurate feature dimensions and improved production yield by maintaining structural integrity and thermal expansion compatibility during the lapping process.
Implementation Method 1
the one or more slider row bars to be mounted on the carrier have a first coefficient of thermal expansion and the bridge has a second coefficient of thermal expansion, wherein the ratio of the second coefficient of thermal expansion to the first coefficient of thermal expansion is less than 1.6
Data Source
AI summary
Embodiments of the present disclosure include carriers for a row bar or stack of row bars to be lapped. In some embodiments, the ratio of the coefficient of thermal expansion of at least the bridge of a carrier to the coefficient of thermal expansion of the slider row bar or stack of slider row bars is less than 1.6. In some embodiments, a carrier can include a bridge having a length longer than the row bar or stack of row bars. In some embodiments, one or more bridge bending members can have junction centerlines offset from the corresponding bridge bending members.