DEVELOPMENT OF THE LATERAL EFFECT PHOTO DIODE TECHNIQUE TO MEASURE OIL FILM THICKNESS

A measurement technique was developed using the lateral effect photodi ode method to determine oil film thickness end ail retention measureme nt. A Position-sensing photodiode determined the change in position of a focused laser beam. The beam was reflected off a diffuse body and c alibrated to varying surface deflections. The calibration showed accur acy to 1 mu m. Samples of tool steel were prepared with a specific sur face topography end then applied with a predetermined amount of heavy white mineral oil. The resulting film of file mineral oil was then obs erved, measured and recorded using the lateral effect photo diode meth od. Experiments were also run with a pin-on-disk machine to measure th e oil film thickness produced at varying sliding speeds. The experimen ts showed that the lateral effect Photo diode technique can measure oi l films in a lab environment.