System for manufacturing a group of head gimbal assemblies (HGAs)
View Patent ↗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 to a predetermined height between 2 and 12 nanometers. 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.
1. A system for manufacturing a group of head gimbal assemblies (HGAs), said system comprising:
a first test disk region including a magnetic layer;
a second test disk region having a plurality of bumps extending therefrom to a predetermined height greater than 2 nm and less than 12 nm;
a rotation mechanism rotating either or both test disk regions;
a positioning mount positioning a head of an HGA selected from the group adjacent the second test disk region;
write/read electronics causing the positioned head to write data to and read data from the first test disk region; and
a sensor for sensing an interaction of the positioned head with one or more of the plurality of bumps.
2. The system of claim 1 , wherein the first and second test disk regions are on one disk.
3. The system of claim 1 , wherein the first and second test disk regions are provided on first and second disks, respectively.
4. The system of claim 1 , 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 said group of head disk assemblies in later manufacture of a quantity of disk drives.
5. The system of claim 1 , wherein the second test disk region is formed by focusing a laser beam on the first test disk region at selected locations to form the plurality of bumps.
6. The system of claim 1 , wherein the sensor includes an acoustic emission sensor affixed to a test arm associated with the head gimbal assembly selected from the group.