MATHEMATICAL-MODELS AND EXPERIMENTS FOR CHIP SIGNALS OF SINGLE-EDGE DEEP HOLE DRILLING

Abstract

Deep hole drilling is applied to holes with depth-diameter ratio larger than 10. The most important prerequisite is the removal of chips because one of the critical problems is chip congestion. This paper presents two models depicting pressure signals that reflect the state of chips. The first model (I), starting from the two-phase slug flow viewpoint, establishes the relationship between the pressure signal and length of the chip. The second model (II), built by considering the fluid force momentum and continuity equation for a control volume, relates the pressure signal with the chip length and radius. The COMputer simulation shows that model I is in good agreement with results from a real cutting process. Experiments conducted in this work also confirms the validity of model II. The proposed models establish fundamental knowledge for the problem of chip state monitoring for deep hole drilling.