Systems and methods for testing magnetic media disks during manufacturing using sliders with temperature sensors
View Patent ↗Systems and methods for testing magnetic media disks during manufacturing using sliders with temperature sensors are provided. One such method involves scanning a surface of a selected disk of a plurality of magnetic media disks using a slider including a magnetic transducer and a temperature sensor, counting a number of the surfaces scanned, determining, during the scanning, whether a threshold crossing event has occurred by determining whether a signal from the temperature sensor signal is not within a preselected range, counting, during the scanning, a number of threshold crossing events, storing, if the number of threshold crossing events is greater than a preselected events limit, the number of surfaces scanned, stopping, if the number of surfaces scanned is greater than a surfaces scanned threshold, the scanning, and returning, if the number of surfaces scanned is less than or equal to the surfaces scanned threshold, to scan a next selected disk.
1. A method for testing magnetic media disks during manufacturing, the method comprising:
(a) scanning a media surface of a selected media disk of a plurality of magnetic media disks, each having a media surface, using a slider comprising a magnetic transducer and a temperature sensor;
(b) incrementing a count of a number of the media surfaces of the plurality of magnetic media disks that have been scanned;
(c) determining, during the scanning of the media surface of the selected media disk, whether a threshold crossing event has occurred by determining whether a signal from the temperature sensor is not within a preselected threshold temperature range;
(d) counting, during the scanning of the media surface of the selected media disk, a number of the threshold crossing events during a preselected time period;
(e) storing, if the number of threshold crossing events is greater than a preselected crossing events limit, the number of the media surfaces scanned;
(f) stopping, if the number of media surfaces scanned is greater than a media surfaces scanned threshold, a scanning of the media surfaces of the plurality of magnetic media disks; and
(g) returning, if the number of media surfaces scanned is less than or equal to the media surfaces scanned threshold, to (a) to scan a next selected media disk of the plurality of magnetic media disks.
2. The method of claim 1 , further comprising modifying, if the number of the media surfaces scanned is less than a preselected media surfaces minimum count for a single slider, a manufacturing process for the plurality of magnetic media disks.
3. The method of claim 1 , further comprising:
repeating (a) to (g) for a plurality of sliders; and
counting a number of sliders tested.
4. The method of claim 3 , further comprising:
modifying, if an average number of the media surfaces scanned for the sliders is less than a preselected media surfaces minimum average count for the sliders, a manufacturing process for the plurality of magnetic media disks.
5. The method of claim 1 :
wherein the (a) scanning the media surface of the selected media disk of the plurality of magnetic media disks using the slider comprising the magnetic transducer and the temperature sensor comprises:
calibrating a head fly height of the slider using the temperature sensor; and
(a) scanning the media surface of the selected media disk of the plurality of magnetic media disks using the slider comprising the magnetic transducer and the temperature sensor.
6. The method of claim 5 :
wherein the preselected threshold temperature range, the number of the preselected crossing events limit, and the media surfaces scanned threshold are each based on information obtained during the calibration of the head fly height.
7. The method of claim 6 , further comprising:
obtaining, during the calibrating of the head fly height of the slider using the temperature sensor, a signal indicative of a surface topography of the selected media disk,
wherein the preselected threshold temperature range corresponds to the signal indicative of the surface topography.
8. The method of claim 1 :
wherein the (a) scanning the media surface of the selected media disk of the plurality of magnetic media disks using the slider comprising the magnetic transducer and the temperature sensor comprises:
initializing the number of media surfaces scanned for the slider to 0; and
(a) scanning the media surface of the selected media disk of the plurality of magnetic media disks using the slider comprising the magnetic transducer and the temperature sensor.
9. The method of claim 1 , wherein the temperature sensor comprises a nano-thermistor stripe sensor.
10. The method of claim 1 , wherein the temperature sensor is disposed on an air bearing surface of the slider.
11. The method of claim 1 , wherein the temperature sensor is configured to indirectly measure a contamination of the slider.
12. The method of claim 1 , wherein the temperature sensor is configured to measure a flying attitude of the slider.
13. The method of claim 1 :
wherein the preselected threshold temperature range is in a range from about 1 degree Celsius less than an operating temperature of the temperature sensor to about 1 degree Celsius greater than the operating temperature of the temperature sensor;
wherein the number of the preselected crossing events limit is in a range from about 50 to about 150; and
wherein the media surfaces scanned threshold is in a range from about 900 to about 1100.
14. The method of claim 1 , wherein the preselected time period is in a range from about 4 milliseconds to about 8 milliseconds.
15. A system for testing magnetic media disks during manufacturing, the system comprising:
a plurality of magnetic media disks, each having a media surface;
a slider comprising a magnetic transducer and a temperature sensor;
a tester configured to test components of a disk drive including the plurality of magnetic media disks using the slider;
the tester configured to:
(a) scan the media surface of a selected media disk of the plurality of magnetic media disks using the slider;
(b) increment a count of a number of the media surfaces of the plurality of magnetic media disks that have been scanned;
(c) determine, during the scan of the media surface of the selected media disk, whether a threshold crossing event has occurred by determining whether a signal from the temperature sensor is not within a preselected threshold temperature range;
(d) count, during the scan of the media surface of the selected media disk, a number of the threshold crossing events during a preselected time period;
(e) store, if the number of threshold crossing events is greater than a preselected crossing events limit, the number of the media surfaces scanned;
(f) stop, if the number of media surfaces scanned is greater than a media surfaces scanned threshold, a scanning of the media surfaces of the plurality of magnetic media disks; and
(g) return, if the number of media surfaces scanned is less than or equal to the media surfaces scanned threshold, to (a) to scan a next selected media disk of the plurality of magnetic media disks.
16. The system of claim 15 , wherein the tester is further configured to:
provide, if the number of the media surfaces scanned is less than a preselected media surfaces minimum count for a single slider, a notice for modifying a manufacturing process for the plurality of magnetic media disks.
17. The system of claim 15 , wherein the tester is further configured to:
repeat (a) to (g) for a plurality of sliders; and
count a number of sliders tested.
18. The system of claim 17 , wherein the tester is further configured to:
provide, if an average number of the media surfaces scanned for the sliders is less than a preselected media surfaces minimum average count for the sliders, a notice for modifying a manufacturing process for the plurality of magnetic media disks.
19. The system of claim 15 , wherein the tester is further configured to:
calibrate, prior to scanning the media surface of the selected media disk, a head fly height of the slider using the temperature sensor.
20. The system of claim 19 :
wherein the preselected threshold temperature range, the number of the preselected crossing events limit, and the media surfaces scanned threshold are each based on information obtained during the calibration of the head fly height.
21. The system of claim 20 , wherein the tester is further configured to:
obtain, during the calibration of the head fly height of the slider using the temperature sensor, a signal indicative of a surface topography of the selected media disk,
wherein the preselected threshold temperature range corresponds to the signal indicative of the surface topography.
22. The system of claim 15 , wherein the tester is further configured to:
initialize, prior to scanning the media surface of the selected media disk, the number of media surfaces scanned for the slider to 0.
23. The system of claim 15 , wherein the temperature sensor comprises a nano-thermistor stripe sensor.
24. The system of claim 15 , wherein the temperature sensor is disposed on an air bearing surface of the slider.
25. The system of claim 15 , wherein the temperature sensor is configured to indirectly measure a contamination of the slider.
26. The system of claim 15 , wherein the temperature sensor is configured to measure a flying attitude of the slider.
27. The system of claim 15 :
wherein the preselected threshold temperature range is in a range from about 1 degree Celsius less than an operating temperature of the temperature sensor to about 1 degree Celsius greater than the operating temperature of the temperature sensor;
wherein the number of the preselected crossing events limit is in a range from about 50 to about 150; and
wherein the media surfaces scanned threshold is in a range from about 900 to about 1100.
28. The system of claim 15 , wherein the preselected time period is in a range from about 4 milliseconds to about 8 milliseconds.