Improving Disk Drive Performance through Simulation: A Case Study on Hutchinson Technology Inc.

Hutchinson Technology Inc.’s Disk Drive Component division is a global maker of disk drive suspension assemblies. As the industry’s only vertically integrated suspension supplier, the company is well positioned to deliver the rapid prototyping, speed to volume, high level of quality and lowest overall costs that disk drive makers require for their current and future products. The company aims to meet customers’ increasing requirements for speed, capacity, and reliability and to maintain its market position in producing complex suspension assemblies.

Hutchinson Technology Inc., a global maker of disk drive suspension assemblies, was facing a significant challenge in the precision of motion of the head suspension assembly in hard disk drives. The airflow-induced vibrations were increasing the uncertainty of the position of the slider, which is crucial for data transfer to and from the disk. This issue was particularly critical in high-speed drives where airflow vibrations were strong and reduced the accuracy of the head assembly. Additionally, in high areal-data density drives, the data track spacing was very fine and small suspension vibrations could significantly reduce drive performance. The company's goal was to meet customers’ increasing requirements for speed, capacity, and reliability and to maintain its market position in producing complex suspension assemblies.

Hutchinson Technology Inc. utilized ANSYS Fluent and ANSYS Mechanical simulation software to address these challenges. The software was successfully benchmarked against experimental data for flow in a simple drive. Fluent and Mechanical simulation software were used to compute the fluid–structure interactions (FSI) in a 3.5 inch actual hard drive operating at 10,000 rpms. The simulation was used to identify vortex shedding within the drive, which played a significant role in causing vibration. The team identified that redesigning certain components could avoid vortex shedding during operation and, consequently, reduce vibration and improve the accuracy of the position of the head. This precise positioning of the head allows for smaller track spacing and consequently higher area density.

• The use of ANSYS Fluent and ANSYS Mechanical simulation software provided Hutchinson Technology Inc. with a comprehensive solution to their challenge. The software allowed the team to identify and address the issue of vortex shedding within the drive, which was causing significant vibration and reducing the accuracy of the head assembly. By redesigning certain components, the company was able to avoid vortex shedding during operation, reduce vibration, and improve the accuracy of the head position. This not only improved the performance of the drives but also allowed for smaller track spacing and higher area density. Additionally, the use of simulation software reduced the need for actual experiments on physical prototypes, resulting in significant time and cost savings.

• Redesign of components reduces vibration and improves accuracy of the head position
• Precise positioning of the head allows for smaller track spacing and higher area density
• Use of simulation software reduced the need for actual experiments on physical prototypes, saving both time (several weeks) and money (several tens of thousands of dollars)