Magnetic Head Flexure Terminal Segmentation for Stress Isolation
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Solution Overview
Problem
The miniaturization of magnetic head assemblies for magnetic disk recording/reproduction has led to issues with stress-induced deformation of flexures, affecting levitation characteristics and reliability due to traditional bonding methods like gold ball bonding and solder ball bonding, which cause stress and deformation, thereby reducing recording/reproduction performance.
Innovation Solution
A magnetic head assembly design featuring a flexure with a slider attachment portion that can warp and a separable flexure terminal portion, connected using a joint that absorbs stress from solder volume shrinkage, maintaining a desired relative angle and preventing deformation of the flexure attachment portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder ball bonding is used to connect the head terminal and flexure terminal, then electrical connection is achieved, but stress is generated due to solder volume shrinkage causing flexure deformation and deteriorating levitation characteristics
Solution Approach 1:
The flexure is divided into a body portion and a terminal portion that can move independently. The terminal portion is separated from the body portion through a gap, allowing it to absorb stress from solder shrinkage without transmitting deformation to the head slider attachment area, thus maintaining manufacturing precision while achieving reliable electrical connection.
Solution Approach 2:
The terminal portion acts as an intermediary between the solder joint and the flexure body. It absorbs the stress generated by solder volume shrinkage through its own deformation, preventing this stress from reaching the head slider attachment portion and causing deformation, thereby protecting the levitation characteristics.
2Reliability
If gold ball bonding is used to connect the head terminal and flexure terminal, then electrical connection is achieved, but the flexure must be firmly fixed which may cause deformation under stress
Solution Approach 1:
The flexure is segmented into a fixed body portion and a movable terminal portion. The body portion maintains structural integrity for firm fixing, while the terminal portion is designed to move and absorb stress, preventing deformation propagation to the head slider attachment area.
Solution Approach 2:
Different parts of the flexure have different mechanical properties. The body portion has high rigidity for stable support, while the terminal portion has lower rigidity to allow stress absorption through deformation, creating local quality differences that resolve the contradiction between firm fixing and stress resistance.
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 ensures good levitation characteristics and improved reliability of the magnetic head assembly by preventing stress-induced deformation, maintaining the desired relative angle and enhancing the performance and reliability of the magnetic disk apparatus.
Implementation Method 1
The volume of solder is shrunk upon solidification and stress is generated such that the head terminal 105 and the flexure terminal 106 are brought close to each other
Implementation Method 2
the flexure has a slider attachment portion supported by the flexure on an end portion and capable of warping
Data Source
AI summary
A disclosed magnetic head assembly (20) is characterized by: a head slider (24); a flexure (23) for supporting the head slider (24); and a signal wiring portion (25) disposed on a surface of the flexure (23), the signal wiring portion (25) transmitting recording current signals or reproduction signals. The flexure (23) has a slider attachment portion (26) supported by the flexure on an end portion and capable of warping and a flexure terminal portion (29) disposed on the end portion relative to an attachment position of the head slider (24) on the slider attachment portion (26) and electrically connected to the signal wiring portion (25). The head slider (24) is fixed on a surface of the slider attachment portion (26) and has a slider terminal portion (32) disposed on a side surface on the end portion and electrically connected to an element portion (31). The slider terminal portion (32) is electrically connected to the flexure terminal portion (29) using a joint portion (40) and the flexure terminal portion (29) is disposed separably from the surface of the surface of the flexure (23).