Method for manufacturing a group of head gimbal assemblies
AssigneeWestern Digital (Fremont), LLC
InventorsVictor K. F. Dunn, Ciuter Chang
Life of this patent
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Abstract
A system and method for the production level screening of low flying magnetic heads in the manufacture of disk drive head disk assemblies (HDAs) is disclosed. A test disk is provided and has a plurality of bumps extending from at least one surface thereof. The test disk is rotated to fly a head of a head gimbal assembly selected from the group adjacent the surface of the test disk. An interaction of the head with one or more of the plurality of bumps may be sensed and the head gimbal assembly may be screened out from the group in response to the sensing of the interaction.
Claims11
A method for manufacturing a group of head gimbal assemblies, the method comprising the following acts:
- providing a test disk having a plurality of bumps extending from at least one surface thereof;
- forming at least a first portion of said plurality of bumps on said test disk to at least a predetermined height;
- rotating said test disk to fly a head of a head gimbal assembly selected from the group adjacent said at least one surface of said test disk;
- sensing an interaction of said head with one or more of said plurality of bumps;
- and
- screening out said head gimbal assembly selected from the group in response to said sensing of said interaction,
- wherein the act of sensing is accomplished temporally adjacent a dynamic electrical test of said head gimbal assembly selected from the group and wherein the predetermined height is between about 2 nm and about 12 nm.
A method for manufacturing a group of head gimbal assemblies the method comprising the following acts:
- providing a test disk having a plurality of bumps extending from at least one surface thereof;
- forming at least a first portion of said plurality of bumps on said test disk to at least a predetermined height;
- rotating said test disk to fly a head of a head gimbal assembly selected from the group adjacent said at least one surface of said test disk;
- sensing an interaction of said head with one or more of said plurality of bumps;
- and
- screening out said head gimbal assembly selected from the group in response to said sensing of said interaction,
- wherein the act of sensing is accomplished temporally adjacent a dynamic electrical test of said head gimbal assembly selected from the group and wherein the predetermined height is greater than a glide avalanche height that is characteristic of a lot of product disks to be used together with the group of head disk assemblies in later manufacture of a quantity of disk drives.
A method for manufacturing a group of head gimbal assemblies the method comprising the following acts:
- providing a test disk having a plurality of bumps extending from at least one surface thereof;
- forming at least a first portion of said plurality of bumps on said test disk to at least a predetermined height;
- rotating said test disk to fly a head of a head gimbal assembly selected from the group adjacent said at least one surface of said test disk;
- sensing an interaction of said head with one or more of said plurality of bumps;
- and
- screening out said head gimbal assembly selected from the group in response to said sensing of said interaction,
- wherein the act of sensing is accomplished temporally adjacent a dynamic electrical test of said head gimbal assembly selected from the group and wherein the predetermined height is less than about a 1.5 sigma lower design limit on a flying height that is characteristic of the group of head gimbal assemblies.
Dependencies are inferred from the claim text.