Experimental aspects of a cam-follower contact

An experimental apparatus for investigations on cam-follower contacts is briefly described and some results related to a tested cam are presented. The apparatus is able to measure the film thickness and shape using optical interferometry and all components of the contact force through a system of nine annular load cells. The equations for the evaluation of the fundamental kinematic quantities of cam-follower pairs are reported. They are applied to the tested cam for detecting the angular positions of the most interesting conditions, as the points of maximum lift, velocity and acceleration, and the trend of the entraining velocity. The methodologies used for recording by a high speed camera connected to a microscope the interference images for the analysis of the lubricated contact are described. Some sample interference images recorded both at low and high magnification are presented showing the different conditions of the contact during a complete rotation of the cam and the capabilities of the experimental apparatus.