R&D: Automatic Scratch Detector for Magnetic Disk

Engineering Access has published an article written by Achinee Polsawat, Ubon Ratchathani University, 85 Sathonlamark Road, Warin Chamrap District, Ubon Ratchathani, Thailand 34190, and Apirat Siritaratiwat, Khon Kaen University, 123 Mitraparp Highway, Khon Kaen , 40002, Thailand.

Abstract: “The development of an automatic scratch detector for a magnetic disk aims to detect scratches on magnetic disk surface at the micrometer level. In hard disk manufacturing industry, it is vital to focus on hard disk quality checking. [Every piece is scrutinized, especially a magnetic disk inspected for scratches. They are occurred during industrial manufacturing processes and by read/write head devices. It may affect data storage performance of magnetic disk.] In this study, scratch detector is operated by reflective method, using the principle of laser reflection (Laser). The beam is sent to disk surface and reflected to photo diode, which is a light receiver. It is found that when the intensity of laser beam received by photo diode reflect on scratched and non-scratched area differently. Light intensity is decreased when it reflects on scratched area. The signal amplitude is between 2.1 – 4.3 volts. It is indicated that the magnetic disk surface is scratched. Finally, it revealed that width of scratch magnetic disk measured by Stereo Microscope (SM) was 30 micrometers in a micrometer scale.“