Smear growth on head slider surface from siloxane outgas on heat assisted magnetic recording

Microsystem Technologies - In this study, the smear by the lubricant and siloxane pickup at the laser heating in the heat assisted magnetic recording (HAMR) was evaluated using our developed...     

Investigation of mechanism of smear formation from diamond-like carbon films on heating

Microsystem Technologies - The formation of head smears during the heat-assisted magnetic recording is a significant problem that must be addressed to ensure the reliability of the head-disk...     

Hybrid lubricant film with high bonding ratio and high coverage

Microsystem Technologies - A hybrid lubricant film was prepared from the perfluoropolyether (PFPE) lubricant (Moresco DDOH), with a single end group, and a PFPE film obtained by depositing the...     

Linear protrusion structure on carriage-arm surface for reduction of flow-induced carriage vibration in hard disk drives

One of the major contributors to head positioning errors is carriage vibration in low frequency due to an air flow caused by disk rotation. It is necessary to suppress the disturbance for Hard Disk Drives (HDDs) to have more capacity. We experimentally studied a reduction in the flow-induced carriage vibration using linear protrusion structures by putting wires on carriage arms. This study was carried out using 2.5?inch HDD which has high rotational speed of 10,000?rpm. We measured position error signals (PES) and compared with a conventional carriage. From the experimental results, we found that the linear protrusion structure was effective to reduce the carriage vibration. Leading edge wire configuration and 2 linear protrusion configuration improved average non-repeatable position errors (NRPE) by 6.9% and 6.4%, respectively.     

Reduction in lubricant pickup by bias voltage between slider and disk surfaces

We studied the effect of bias voltage between slider and disk surfaces to reduce lubricant pickup by the slider. A perfluoropolyether (PFPE) lubricant film, which is coated on the disk surface, has been considered to be charged to a negative voltage by the airflow on the rotational disk surface. Because the PFPE lubricant film is negatively charged, the lubricant pickup should be reduced by a bias voltage with a negative voltage on the slider surface. We confirmed changes in the lubricant pickup in a lubricant pickup test conducted at different bias voltages. A positive voltage of the slider accelerated the lubricant pickup, whereas a negative voltage reduced it.     

Numerical study on the effects of linear protrusion on flow-induced carriage excitation force in hard disk drives

The positioning accuracy of magnetic heads needs to be improved to increase the recording capacity of hard disk drives. In our previous study, experimental results confirmed that the head-positioning error could be decreased by attaching linear protrusions on the leading edge of the carriage arms. However, the mechanism underlying the phenomenon has not been elucidated. In the present research, we evaluated the effect of leading-edge protrusions on the flow-induced carriage excitation force using computational fluid dynamics (CFD) analysis and the Hilbert–Huang transform (HHT). We prepared two carriage-arm models, with and without linear protrusions, on the leading edges of the arm, and performed the CFD analyses. Subsequently, we conducted a frequency analysis by applying HHT to the simulated disturbance torque time-series of each carriage-arm model and compared the results. Our results show that the leading-edge protrusions decrease the disturbance torque due to the flow fluctuation between the arm and disk and in the wake flow, although the low-frequency disturbance torque due to the pulsatile flow can be deteriorated.