Real-time fuzzy logic control for maximising the tool life of small-diameter drills

Drilling of small-diameter holes is an important yet difficult machining process. This, however, is commonly done on machines with hand feeding as the drill breakage is a critical and most trouble making issue in an automated manufacturing system. In most production factories, in order to reduce risk of tool breakage, cutting tool are repalced based on an average tool life and are not used as long as they can work. To tackle the problem, a simpler yet more effective method is introduced to develop a fuzzy logic controller based on the on-line diagnosis of drill conditions for automated small-diameter drilling operations. Experimental work has been conducted to obtain the process information and observe the system behaviours which are interpreted by using systematic analysis as an aid to the design of fuzzy logic controller. The methodology presented in this paper is expected to be applied to automated machining systems to improve the drilling process performance and reduction of production costs by maximising the use of drill life and preventing drill failures.