Abstract
Micro-hole drilling is experiencing a very rapid growth in precision production industries. The micro-drills play a critical role in manufacturing industry. There are many factors which influence the micro-drill performance including the drill point geometry, the drill material, and the workpiece material, among which the most fundamental factor is the drill point geometry. In this paper, a new micro-drill point geometry, termed the centering micro-drill point, is developed. A mathematical model for this new micro-drill point has been established. Micro-drilling tests in AISI 1045 steel are performed with different cutting conditions. By contrasting centering micro-drill and planar drill point micro-drill, the cutting performance of the centering micro-drill has been investigated. The results showed that, when the cutting speed is 35 m/min and the feed rate is 44 mm/min, the thrust force of the centering micro-drill reduces by 21.7% than that of planar micro-drill and the drilling hole amounts increase by 13.5%. The roundness of the thirtieth hole drilled by centering micro-drill is 1.02, and it is 1.08 by planar micro-drill; the centering micro-drill has better position accuracy than planar micro-drill, and further gets good size and shape accuracy.