"Typical Audio Measurements In Oscilatory Ball Milling Processes And Its Relationship With The RateOf Energy Transferred To The Powder"

CUADRADO- LABORDE, CHRISTIAN; LAURA CRISTINA DAMONTE; MENDOZA ZELIS, LUIS

MATERIALS SCIENCE FORUM

TransTech Publications

Año: 2004 vol. 20 p. 169 - 174

0255-5476

Abstract. Sound register during the milling process by means of a simple piezoelectric device and a sound card may be a valuable tool to determine the kinematics and dynamics of the impacts. Standard signal analysis could be reliably used to estimate the impact power transferred to the powders in ball milling processes. Total harmonic distortion (the harmonic to fundamental power ratio) –including noise or not- and the total root mean square power, among other sound parameters, reveal as accurate indicators of this impact power. It is worth to note that this accurate sensitivity goes further than clipping effects (overload condition where the input signal strength exceeds the full scale sensitivity of the sound card input), situation which is commonly achieved in ball milling measurement. In this paper we discuss the application of this kind of ¨in situ¨ measurements to a vibratory ball mill and report the possibility to detect possible drops in the rate of energy transfer at some particular oscillation frequencies. sound card may be a valuable tool to determine the kinematics and dynamics of the impacts. Standard signal analysis could be reliably used to estimate the impact power transferred to the powders in ball milling processes. Total harmonic distortion (the harmonic to fundamental power ratio) –including noise or not- and the total root mean square power, among other sound parameters, reveal as accurate indicators of this impact power. It is worth to note that this accurate sensitivity goes further than clipping effects (overload condition where the input signal strength exceeds the full scale sensitivity of the sound card input), situation which is commonly achieved in ball milling measurement. In this paper we discuss the application of this kind of ¨in situ¨ measurements to a vibratory ball mill and report the possibility to detect possible drops in the rate of energy transfer at some particular oscillation frequencies. Sound register during the milling process by means of a simple piezoelectric device and a sound card may be a valuable tool to determine the kinematics and dynamics of the impacts. Standard signal analysis could be reliably used to estimate the impact power transferred to the powders in ball milling processes. Total harmonic distortion (the harmonic to fundamental power ratio) –including noise or not- and the total root mean square power, among other sound parameters, reveal as accurate indicators of this impact power. It is worth to note that this accurate sensitivity goes further than clipping effects (overload condition where the input signal strength exceeds the full scale sensitivity of the sound card input), situation which is commonly achieved in ball milling measurement. In this paper we discuss the application of this kind of ¨in situ¨ measurements to a vibratory ball mill and report the possibility to detect possible drops in the rate of energy transfer at some particular oscillation frequencies.