Evaluation of Vibration Measurements at Rock Drilling

Abstract

The paper presents a method for vibration measurements at rotary drilling of andesite, granite and limestone. The measurements were carried out on the drilling stand using diamond-impregnated bits of 46 mm diameter. The vibration signal was monitored by the Microlog CMVA55 at constant input parameters (constant thrust or constant revolutions). The revolutions were changed from 3,33 s-1 to 23,33 s-1 stepwise by 3,33 s-1. Similarly, at constant revolutions 16,66 s-1 the thrust was set to 5500, 7500, 9500 and 11500 N.The results of vibration signal analysis in the frequency domain are presented further in the paper. The aim of the vibration measurement is to study the mechanism of rock disintegration. The Vibration frequency spectrum contains a significant amplitude, which denotes the frequency of revolutions of the drilling tool. The Frequency spectrum of measurements contains also higher harmonic and subharmonic frequencies. There are significant sidebands in the surround of higher harmonic frequencies. The results show that the vibration measurement may be used for the identification of regime parameters at the rock drilling.

Keywords

• rock disintegration
• drilling
• vibration signal
• vibration spectrum