Malcomb, J., "Laser Profilometry For Non-Contact Automated Countersink Diameter Measurement," SAE Int. J. Aerosp. 7(2):263-268, 2014, doi:10.4271/2014-01-2255.
Automated countersink measurement methods which require contact with the workpiece are susceptible to a loss of accuracy due to cutting debris and lube build-up. This paper demonstrates a non-contact method for countersink diameter measurement on CFRP which eliminates the need for periodic cleaning. Holes are scanned in process using a laser profilometer. Coordinates for points along the countersink edge are processed with a unique filtering algorithm providing a highly repeatable estimate for major and minor diameter.