Drill bit flank wear monitoring system in composite drilling process using image processing

Abstract

Composite drilling is a hole making operation that is mainly involved in aircraft manufacturing industry. The poor machinability of the composite materials causes the cutting tool to wear faster and increasing the production cost. Ignoring the tool condition would be a bad idea for the production as worn cutting tool tends to damage the highly expensive composite panel of the aircraft. Tool condition monitoring (TCM) is required to keep the process in balance between cost and quality. This paper presents a system to perform tool condition monitoring of a drill bit flank wear using image processing approach. The real industrial sample of carbide drill bit which was used to drill carbon fibre composite panel is obtained directly from the manufacturing assembly line. The images of the drill bit are acquired from the top view for every 100 holes using the developed hardware system. Edge detection is used to detect the boundary of the cutting lips and the images are compared with the reference image of the brand new drill bit using image registration method. The wear rate of the erosion flank wear measured is recorded at average rate of 0.0198% per hole and considered worn at maximum amount of 25.48% wear.