A check shows that the above Eq. (1) is consistent with the ratio of maximum normal stresses for different radii of curvature given by Suk and Gillis 1, whereas the authors’ Eqs. (12)–(13) are in contradiction to it. A further check shows that the authors’ Eqs. (12)–(13) are not consistent with the Hertz’s solution 2 which is also cited as Eqs. (2) and (5) by the authors.
This leads to another problem with respect to the authors’ extrapolation results. Based on the above Eq. (1), we re-estimate the desired parameters for a dynamic load slider in terms of the same stress level as defined by the authors. The obtained radii of curvatures are summarized in Table 1. From the table, it can be seen that there are significant differences between the results obtained from the above Eq. (1) and the authors’ results.
|Extrapolated radius of curvatures of Nano slider and Pico slider needed to achieve at least 100,000 cycles of dynamic load head-disk interface durability with a vertical loading speed of 50 mm/s|
We still remain impressed by the depth of the paper, even though we wish the authors’ model to be consistent and the extrapolated results to be more accurate.
Singapore Research Laboratory, Sony Electronics (Singapore) Pte Ltd. 10 Science Park Road #03-08, Alpha Building, Singapore Science Park II, Singapore 117684.