Vibration Measurement at Outlet Nozzle for Optimizing Steel Grit Blasting

This paper deals with enhanced control of blasting via processing of vibration signals. In the blasting process, a mixture of abrasive and air under pressure is fed to the workpiece. However, the pressure set by the operator in the compressor is not always the same as the pressure in the end nozzle; it can decrease due to the passage of the mixture through a longer supply hose. Our research was focused on classifying vibration signals measured in the outlet nozzle according to the mixture pressure. The developed algorithm is based on a smooth spectrum of vibrations obtained by the linear prediction method. To achieve optimal results, vibration signals from several sensing options were measured and compared in tests involving three types of accelerometers and three different positions of accelerometer placement on the nozzle, with regard to vibrations in the axial and radial directions. The best classification accuracy of 90.8% was achieved for a pressure resolution of 2 bars when measuring axial vibrations on the nozzle holder. Monitoring the outlet pressure of the mixture can improve existing blasting systems by improving the ability to automatically maintain optimal operating pressure during blasting.