System and method for particle monitoring for a head disk assembly to detect a head disk interface event
View Patent ↗Disclosed is a system and method for particle monitoring for a head disk assembly (HDA) to detect a head disk interface (HDI) event. A particle monitoring system includes a particle detector, an air sampling device, and a computer. The air sampling device is coupled to and in fluid communication with the particle detector. The air sampling device extends into the HDA to obtain an air sample. The particle detector is used to detect particles contained in the air sample. The computer is coupled to the particle detector and is configured to: monitor the particles detected by the particle detector; and declare an HDI event if the particles detected in the air sample match a pre-defined characteristic.
1. A particle monitoring system for a head disk assembly (HDA), the HDA comprising at least a disk, an actuator arm, and a head connected to a distal end of the actuator arm in which the actuator arm is rotatable about a pivot to position the head radially over the disk, the particle monitoring system comprising:
an air sampling device extending into the HDA to obtain an air sample;
a particle detector external to the HDA coupled to and in fluid communication with the air sampling device, the particle detector operable to detect particles contained in the air sample; and
a computer coupled to the particle detector, the computer configured to:
monitor the particles detected by the particle detector; and
declare a head disk interface (HDI) event if the particles detected in the air sample match a pre-defined characteristic.
2. The particle monitoring system of claim 1 , wherein the air sampling device includes a tube that extends into the HDA.
3. The particle monitoring system of claim 1 , wherein the air sampling device is configured to sample a pre-defined volume of air from the HDA at a pre-defined air-flow rate for a pre-defined amount of time.
4. The particle monitoring system of claim 3 , wherein the particle detector further comprises a photocell to detect particles, such that when a particle passes through the photocell, a voltage drop occurs that is converted into a particle indication signal that is transmitted to the computer.
5. The particle monitoring system of claim 4 , wherein the particle detector is configured to detect particles having at least a 0.2 micron diameter.
6. The particle monitoring system of claim 4 , wherein the particle indication signals are utilized by the computer to determine if the particles detected in the air sample match the pre-defined characteristic.
7. The particle monitoring system of claim 6 , wherein the pre-defined characteristic corresponds to a pre-defined number of particle indication signals being received by the computer in the pre-defined interval of time.
8. The particle monitoring system of claim 1 , wherein if the computer declares the HDI event, the computer provides an indicator that at least the disk of the HDA should be quarantined.
9. The particle monitoring system of claim 1 , wherein the particle monitoring system monitors for the HDI event as part of a head merge process in an assembly of a disk drive.
10. The particle monitoring system of claim 1 , wherein the particle monitoring system monitors for the HDI event as part of an internal servo-writing process.
11. The particle monitoring system of claim 1 , wherein the particle monitoring system monitors for the HDI event as part of an external servo-writing process.
12. A method to detect a head disk interface (HDI) event occurring in a head disk assembly (HDA), the HDA comprising at least a disk, an actuator arm, and a head connected to a distal end of the actuator arm in which the actuator arm is rotatable about a pivot to position the head radially over the disk, the method comprising:
obtaining an air sample from the HDA;
detecting particles contained in the air sample external to the HDA;
determining if the particles detected in the air sample match a pre-defined characteristic; and
if the particles match the pre-defined characteristic, declaring a head disk interface (HDI) event, the HDI event representing contact between the head and the disk.
13. The method of claim 12 , further comprising sampling a pre-defined volume of air from the HDA at a pre-defined air-flow rate for a pre-defined amount of time.
14. The method of claim 12 , wherein detecting the particles contained in the air sample and determining if the particles detected in the air sample match the pre-defined characteristic further comprises:
detecting when a particle passes through a photocell;
generating a particle indication signal when the particle passes through the photocell;
detecting particle indication signals; and
determining if the detected particle indication signals match the pre-defined characteristic, the pre-defined characteristic corresponding to a pre-defined number of particle indication signals occurring in a pre-defined period of time.
15. The method of claim 12 , wherein, if the HDI event is declared, further comprising providing an indicator that at least the disk of the HDA should be quarantined.
16. The method of claim 12 , wherein determining whether the particles detected in the air sample match the pre-defined characteristic occurs as part of a head merge process in an assembly of the disk drive.
17. The method of claim 12 , wherein determining whether the particles detected in the air sample match the pre-defined characteristic occurs as part of an internal servo-writing process.
18. The method of claim 12 , wherein determining whether the particles detected in the air sample match the pre-defined characteristic occurs as part of an external servo-writing process.
19. In a particle monitoring system to detect a head disk interface (HDI) event occurring in a head disk assembly (HDA), the HDA comprising at least a disk, an actuator arm, and a head connected to a distal end of the actuator arm in which the actuator arm is rotatable about a pivot to position the head radially over the disk, a computer-readable medium having stored thereon instructions, which when executed by a computer cause the computer to perform the operations comprising:
detecting particle indication signals received from a particle detector external to the HDA, each particle indication signal corresponding to a particle detected by the particle detector, the particle detector coupled to and in fluid communication with an air sampling device that extends into the HDA to obtain an air sample; and
determining whether the particle indication signals match a pre-defined characteristic, and, if so, declaring an HDI event, the HDI event representing contact between the head and the disk.
20. The computer-readable medium of claim 19 , wherein if the HDI event is declared, further comprising instructions to cause the computer to provide an indicator that at least the disk of the HDA should be quarantined.
21. The computer-readable medium of claim 19 , wherein the pre-defined characteristic corresponds to a pre-defined number of particle indication signals occurring in a pre-defined period of time.
22. The computer-readable medium of claim 19 , wherein the operation of determining whether the particle indication signals match the pre-defined characteristic for the HDA occurs as part of a head merge process in an assembly of a disk drive.
23. The computer-readable medium of claim 19 , wherein the operation of determining whether the particle indication signals match the pre-defined characteristic for the HDA occurs as part of an internal servo-writing process.
24. The computer-readable medium of claim 19 , wherein the operation of determining whether the particle indication signals match the pre-defined characteristic for the HDA occurs as part of an external servo-writing process.