Experimental investigation on drilling efficiency of a percussive ultrasonic drill

Deen Bai, Zhijun Zhao, Yubao Cao, Qiquan Quan, He Li, Zongquan Deng

Abstract: Drilling is an important method to obtain samples on a minor planet for deep-space exploration. Conventional drilling devices driven by electromagnetic motors usually need large weight on bit to fracture hard rocks. It is a great challenge for conventional drilling devices to drill on a minor planet which has a weak gravitational field. Compared with conventional drilling devices, ultrasonic drills which employ the high frequency longitudinal vibration of Langevin transducers to fracture rocks, have the advantages of small size, low power, low weight on bit, making them suitable for extraterrestrial rock sampling. The weight on bit, restoring force, spring rate, and free mass have effect on the drilling efficiency of the ultrasonic drills. This paper focus on experimental studying of the effect of these factors on drilling speed of a percussive ultrasonic drill (PUD). Two kinds of experiment methods (single factor experiment and orthogonal array experiment) were utilized to complete the experimental study. Experimental results indicate that the weight on bit has a larger effect on the drilling speed than spring rate and free mass. Moreover, the restoring force has little effect on drilling speed.