DRILLING TORQUE - A DIAGNOSIS CRITERION OF THE DRILL WEAR

Abstract

Drill life estimation is usually made on the basis of the maximum admissible wear which, unfortunately, is given in a too large range in the literature. Taking into account that the durability distribution depends in a great measure on the adopted value for the admissible wear, in the paper the critical value for drilling torque is proposed as an objective criterion for drill wear limit. In this sense, a relationship between the flank wear and the drilling torque is established and a definition of the critical value of this torque is given. The proposed method is proved by tests made on a batch of HSS drills.