Disk Drive Baseplate Boss Surface Roughness for Torque Retention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current disk drive suspension baseplates have limited torque retention due to smooth boss outer surfaces, which restricts the mechanical connection with actuator arms, necessitating higher swage forces and potential warping of the flange during swaging.
Innovation Solution
Manufacturing baseplates with boss outer surfaces characterized by increased roughness parameters (Ra≥0.15 μm, Rq≥0.2 μm, H≥0.5 μm) through a multi-step process involving passivation and chemical etching, using acid baths and specific etchant compositions to enhance surface roughness and torque retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the boss outer surface is made smooth through chemical polishing, then the surface quality is improved, but the torque retention between the baseplate and actuator arm deteriorates
Solution Approach 1:
The patent applies different surface treatments to different locations: the ball insertion hole inner circumference receives chemical polishing for smoothness, while the boss outer surface receives chemical etching for roughness. This local differentiation allows each surface to have the properties needed for its specific function.
Solution Approach 2:
Instead of polishing the boss outer surface to improve it as conventionally done, the patent inverts the approach by deliberately roughening it through chemical etching. This inverted approach creates surface irregularities that enhance friction and torque retention between the baseplate and actuator arm.
2Reliability
If higher swage forces are applied to improve torque retention, then the mechanical connection strength is improved, but the flange warping increases
Solution Approach 1:
The patent changes the surface roughness parameter of the boss outer surface through chemical etching, creating a rougher surface with higher friction characteristics. This parameter change allows torque retention to be improved without requiring increased swage force, thereby preventing flange warping.
3Reliability
If the actuator arm thickness is increased to improve mechanical connection, then the torque retention is improved, but the drive height increases
Solution Approach 1:
The patent changes the surface roughness parameter of the boss outer surface to enhance friction-based torque retention. This allows thinner actuator arms to achieve satisfactory torque retention, thereby reducing the overall drive height without compromising mechanical connection reliability.
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 enhanced surface roughness significantly improves torque retention, allowing for lower swage forces, reduced warping, and thinner actuator arms, enabling closer disk spacing and a smaller drive height while maintaining satisfactory mechanical connection.
Implementation Method 1
Manufacturing baseplates with boss outer surfaces characterized by increased roughness parameters (Ra≥0.15 μm, Rq≥0.2 μm, H≥0.5 μm) through a multi-step process involving passivation and chemical etching, using acid baths and specific etchant compositions to enhance surface roughness and torque retention.
Implementation Method 2
Manufacturing baseplates with boss outer surfaces characterized by increased roughness parameters (Ra≥0.15 μm, Rq≥0.2 μm, H≥0.5 μm) through a multi-step process involving passivation and chemical etching
Implementation Method 3
The static coefficient of friction can be improved by changing the surface roughness of the baseplate... The enhanced surface roughness significantly improves torque retention, allowing for lower swage forces
Data Source
AI summary
Disk drive suspension baseplates made of a base metal and methods for manufacturing disk drive suspension baseplates having boss outer surfaces characterized by roughness parameters Ra≥0.15 μm.