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Contamination-Free Balancing of Spindle/Hub Motors

IP.com Disclosure Number: IPCOM000036767D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Davison, J: AUTHOR [+4]

Abstract

A method is described to balance disk file hubs and spindle motors by removing material without generating contamination. Cleanliness levels are unaffected.

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This is the abbreviated version, containing approximately 63% of the total text.

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Contamination-Free Balancing of Spindle/Hub Motors

A method is described to balance disk file hubs and spindle motors by removing material without generating contamination. Cleanliness levels are unaffected.

Electromechanical devices, such as disc drives, have critical cleanliness requirements. Many smaller disc drives incorporate a combined disc hub and spindle motor assembly. The disc hub usually requires critical balancing as a final manufacturing operation. This balancing is often achieved by REMOVING hub material, usually by drilling. Balancing by ADDING material is often prohibited by the disc file design. Two balancing operations may be required; the first on the spindle/hub alone, and the second balancing after the attachment of data storage discs.

In the case of spindle/hub motors, balancing by drilling poses a number of contamination problems. Conventional solvent cleaning after metal removal would permanently degrade the bearing performance. Particulate debris therefore must be prevented from affecting the spindle bearings and, ultimately, the disc drive assembly. If the hub is made from ferritic material, magnetic attraction can further compound the potential contamination problems. Thus after the addition of recording discs, balancing by drilling of metal is obviously forbidden.

Critical mechanical balance is achieved by the use of a high power laser. The laser contact point is shrouded, and the ablation vaporized material is removed by vacuum. The m...