Measurement of head wear rates using custom high sensitivity electrical elements

A technique for measuring the wear rate of a tape recording head is described that can produce a theoretical dimensional resolution of 0.02 nm. Custom four wire elements are located in the gap of the actual recording head design to be tested (rather than using substitutes) and can be strategically placed to measure the wear rate across the width of the tape. Temperature compensation is achieved by measurement of a spare identical element in the head structure set back from the wear surface such that it does not receive wear. The wear rate at various locations across the head gap lines of NiZn ferrite heads have thus been obtained continuously as a function of the amount of CrO₂ tape passed and show that the wear rate is greater near the tape edges. Due to the high sensitivity of the test elements, use of long reels of tape and placement of multiple heads in the same tape path, comparisons of head contour shape and/or materials can be made in a very short test time