Small hole drilling of titanium alloy

Relation ship between variation of machining force and drill failure

Abstract

In this study, high-speed steel drills 0.5, 1.0, and 1.5 mm in diameter are employed in drilling titanium alloy for basic drill failure data acquisition. First, the relationships between drilling depth, cutting force, and failure are investigated in conventional drilling. The cutting force is considered in three divisions: stability region, rising region, and unstable region. The relation of rising ratio of thrust force in the rising region of cutting force to drilling depth is clarified. Next, step feed drilling was examined for each drill diameter. Cutting force is also unstable as in the case of conventional drilling when drill failure occurred. Finally, the aspect ratio was more than 10 in step feed drilling with each drill diameter.