Browse Prior Art Database

Small Disk-to-Disk Spacing Heads Merging in Head/Disk Assembly

IP.com Disclosure Number: IPCOM000112643D
Original Publication Date: 1994-Jun-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 98K

Publishing Venue

IBM

Related People

Malek, SS: AUTHOR [+3]

Abstract

Merging heads on disk has always been one of the obstacles facing the desire to reduce disk-to-disk spacing to increase volumetric capacity. This process step is one of the major contributors to yield impacts. Disclosed is a concept that demonstrates the loading of heads on disks that are spaced 1.83 mm apart by implementing an innovative algorithm utilizing a rectangular robot, blade-like fingers, and computer vision feedback. This conceptual solution can address multiple models of a product across flat, tub, or clamshell base castings.

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Small Disk-to-Disk Spacing Heads Merging in Head/Disk Assembly

      Merging heads on disk has always been one of the obstacles
facing the desire to reduce disk-to-disk spacing to increase
volumetric capacity.  This process step is one of the major
contributors to yield impacts.  Disclosed is a concept that
demonstrates the loading of heads on disks that are spaced 1.83 mm
apart by implementing an innovative algorithm utilizing a rectangular
robot, blade-like fingers, and computer vision feedback.  This
conceptual solution can address multiple models of a product across
flat, tub, or clamshell base castings.

      The disk drive is loaded in the fixture and clamped into proper
orientation.  The robot moves the end arm fingers through a taught
path to arrive at the initial position adjacent to the actuator
suspensions outside the disk's pack.  Using a acquired image, the
vision system calculates the adjustment necessary to align the
fingers to grasp the suspensions safely.  The robot moves the fingers
based on the reported clearance adjustment for the suspensions from
the vision system.  This adjustment is needed to compensate for
variations among various shipping comb, fixture, and other product
component tolerances.  The fingers are rotated in between the
suspensions.  The end arm fingers move to compress the suspension.
After the shipping comb is removed, we use a second acquired image.
The vision system calculates the necessary offset to center the heads
between the disks.  The nominal center position of disks is trained
offline using a typical part.  The vision system calculates the
offset of the disks from the trained nominal disk positions.  The
vision system locates the heads relative to the disks, and reports
the necessary adjustments to center the heads between the disks.  The
robot moves the fingers based on the vision system feedback.  This
process is repeated until the vision system reports an acceptable
clearance for both heads.

      The system is designed for alignment, inspection, and
connectivity analysis.  The system supports normalized correlation
search and golden template comparison with changes in translation,
rotation, and scale.  The normalized correlation is accurate to one
quarter pixel, with or without any amount of rotation.  Its golden
template comparison finds one pixel defects with or without rotation
and scale variation.  Connectivity analysis is supported for black
and white features.  It has optical character recognition (OCR)
capability for some standard parts.

      The image is compressed from a two-dimensional row and column
image to a one-dimensional image...