Asymmetrically Wrapped Flat-Profile Tape-Head Friction and Spacing

In this work, we study the friction and spacing between a magnetic data storage tape and a recording head. The tape-head friction force and magnetic spacing are measured as a function of the angles with which the tape is wrapped around the read/write head at 2 and 6 m s(-1) tape transport velocity. It is found that the friction force can be described as a linear function of the leading and trailing wrap angles, where the friction force increases for increasing wrap angles. The analysis treats the total friction force as the sum of three components resulting from (1) the leading edge, (2) the head surface, and (3) the trailing edge. Coefficients of friction are calculated for each of the three components from experimental data. The leading edge and head surface components are both dependent on the leading-edge wrap angle and independent of the trailing-edge wrap angle, whereas the trailing-edge component is only dependent on the trailing-edge wrap. In addition, the estimated magnetic spacing is found to decrease with increasing leading-edge wrap angle, but is independent of the trailing-edge wrap angle, even for negative trailing-edge wrap angles. Hence, the trade-off between friction and spacing can be optimized through judicious choice of the wrap angles. In addition, we find that a significant portion of the friction is due to edge friction (as high as 70 % in the case of symmetric wrap). Therefore, we conclude that modifications to the head surface topography to reduce the contact area may not result in a significant reduction in head-tape friction.