THE IMPACT OF CERTAIN WORKING PARAMETERS ON THE DRILLING PROCESS OF PERCUSSIVE-ROTARY DRILLING

Bui-Van HAI; Le-Duc HIEU; Nguyen-Phi TRUONG; Lam-Quang VINH; Khong-Van Nguyen

Bui-Van HAI School of Mechanical and Automotive Engineering Hanoi University of Industry
Le-Duc HIEU School of Mechanical and Automotive Engineering Hanoi University of Industry
Nguyen-Phi TRUONG Faculty of power engineering, Phu Tho College of Electromechanics
Lam-Quang VINH Faculty of power engineering, Phu Tho College of Electromechanics
Khong-Van Nguyen Hung Yen University of Technology and Education

Abstract

This study examines the impact of critical operational factors on the efficacy of rotary-percussive drilling through a multibody dynamic model developed using Lagrange's equations, whereby the rock is represented as a visco-elastic-plastic material. The characteristics examined encompass impact frequency, impact impulse, and rock rigidity. Simulation results demonstrate that with a rock stiffness of k = 5×10⁸ N/m, the ideal impact frequency is between 50 and 70 Hz, achieving maximum drilling efficiency at roughly 65 Hz. As the impact impulse escalates from 120 kN to 280 kN, the ideal frequency transitions from 55–65 Hz to 75–85 Hz. Furthermore, as rock rigidity escalates from 8.93×10⁷ to 8.4×10⁸ N/m, the ideal impact frequency accordingly climbs from 32 Hz to 69 Hz. The findings indicate that drilling efficiency is significantly influenced by the interplay of impact parameters and rock mechanical properties, establishing a solid foundation for the selection of optimal operating settings to improve drilling performance and minimize energy losses.