EFFECT OF AIRBORNE CONTAMINANTS ON MAGNETIC HEAD WEAR

The present study systematically investigates the effect of airborne c ontaminants on the magnetic head wear of a helical scan videotape reco rder (VTR). Experiments were performed to investigate the internal wea r particle generation, and the effect of airborne contaminants on the head wear and signal error rates. The flow field around the scanner wa s also studied numerically. Particle concentrations were measured at v arious locations around the scanner. It was found that particle concen trations are highest at the inlet-the interface where the tape first m eets the scanner. This indicates that wear particles accumulated at th e inlet location. Numerical simulation of the flow field around the ro tating scanner shows the air around the scanner enters at the inlet an d exits at the outlet-the interface where the tape detaches from the s canner, causing a recirculating region around the scanner. Airborne co ntaminants in the surrounding air can enter the inlet and cause abrasi on wear between the head and the tape. The head wear rate increases wi th particle size and concentration. Ionic gaseous contaminants such as SO2 and HNO3 also increase the head wear rate. Signal error rate was found to be increased when the VTR operated in a contaminated environm ent. (C) 1997 Elsevier Science S.A.