Investigation of tape edge wear of magnetic recording tapes

To increase the storage capacity of magnetic tape, track density must be increased. Increase in track density requires better tape guiding since the maximum track density is limited by lateral tape motion. Tape guiding is done by using flange rollers or pressure pads in most tape drives. However, sliding contact between the guides and tape edge causes tape edge wear and results in an increase in lateral tape motion. Therefore, a comprehensive study of tape edge wear is necessary to improve the storage density of tapes.; In this study, tape edge wear is investigated as a function of the number of wear passes, guide force, speed, tape tension, substrate, and guide surface roughness. A measurement technique was developed to measure tape edge wear by monitoring the change of depth of artificially made indentations on a tape edge using atomic force microscopy. An optical sensor was employed to measure lateral tape motion. The relationship between lateral tape motion and tape edge wear was correlated. A rotating drum tester was built to accelerate tape edge wear and a tri-layer sandwich model was derived to predict tape edge wear. Numerical simulation of tape edge wear was implemented using Archard's wear equation at each node. Finally, the mechanical properties of tape substrates (e.g. PET and PEN films) were investigated using a nanoindenter.; The experimental results show: (1) Tape edge wear is affected by the operational conditions of the tape drive as well as the mechanical properties of tape substrate. (2) Tape edge wear results in an increase in lateral tape motion. Also, tape edge wear can be accelerated using an accelerated wear tester. (3) Tape edge wear can be predicted accurately using a tri-layer sandwich model. (4) The moduli of PET and PEN films depend strongly on the orientation of the films after stretching.; Simulation results reveal the mechanism of tape edge wear. Initially, high points on the tape edge experience large contact forces and show significant wear. As the number of wear passes increases, the tape edge becomes smoother and eventually the stress is distributed uniformly on the tape edge surface.