Methods and apparatus for controlling the lapping of a slider based on an amplitude of a readback signal produced from an externally applied magnetic field

• Main Authors: BEAUCAGE JACEY ROBERT, CRAWFORTH LINDEN J, WU XIAO Z
• Format: Patent
• Language: English
• Published: 17.06.2008
• Subjects: COMBINED OPERATIONS; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS; GRINDING; INFORMATION STORAGE; MACHINE TOOLS; MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; METAL-WORKING NOT OTHERWISE PROVIDED FOR; OTHER WORKING OF METAL; PERFORMING OPERATIONS; PHYSICS; POLISHING; STATIC STORES; TRANSPORTING; UNIVERSAL MACHINE TOOLS

The lapping of a slider is controlled based on an amplitude of a readback signal which is produced from an externally applied magnetic field. A lapping plate is used to lap a slider which includes at least one magnetic head having a read sensor. During the lapping, a coil produces a magnetic field around the slider and processing circuitry monitors both a readback signal amplitude and a resistance of the read sensor. The lapping of the slider is terminated based on the monitoring both the readback signal amplitude and the resistance. Preferably, the lapping of the slider is terminated when the resistance is within a predetermined resistance range and the readback signal amplitude is above a predetermined minimum amplitude threshold or reaches its peak value. Asymmetry can also be measured in the described system, where the lapping process is terminated based on asymmetry as well as resistance and amplitude measurements.