Effect of airborne contaminants on magnetic head wear

Abstract

The present study systematically investigates the effect of airborne contaminants on the magnetic head wear of a helical scan videotape recorder (VTR). Experiments were performed to investigate the internal wear particle generation, and the effect of airborne contaminants on the head wear and signal error rates. The flow field around the scanner was also studied numerically. Particle concentrations were measured at various locations around the scanner. It was found that particle concentrations are highest at the inlet—the interface where the tape first meets the scanner. This indicates that wear particles accumulated at the inlet location. Numerical simulation of the flow field around the rotating scanner shows the air around the scanner enters at the inlet and exits at the outlet—the interface where the tape detaches from the scanner, causing a recirculating region around the scanner. Airborne contaminants in the surrounding air can enter the inlet and cause abrasion wear between the head and the tape. The head wear rate increases with particle size and concentration. Ionic gaseous contaminants such as SO 2 and HNO 3 also increase the head wear rate. Signal error rate was found to be increased when the VTR operated in a contaminated environment.