Estimação espectral do sinal de vibração para o monitoramento do desgaste do dressador de ponta única

Abstract

The use of dressers worn can provide a less aggressive to the grinding wheels, causing an increase in cutting forces and a more rapid loss of grinding grain consequently compromise the final quality of the workpiece to be machined. On the other hand, a method of monitoring the dressing operation in real time, identifying the moment in which the dresser is worn and thus to be replaced, something which can be of great importance for the grinding process in order to assure quality and accuracy of the workpieces. Thus, this study aimed to evaluate the wear of the single point dresser, through spectral analysis of vibration signal during the dressing operation. For this dressing assays were performed using a flat grinding and input variables a grinding wheel aluminum oxide, one the single point dresser of synthetic diamond r type CVD (Chemical Vapour Deposition), depth of dressing 40 μm, dresser speed of 3.45 mm /s and the degree of coating Ud equal to 1 at the beginning of dressing. The output variables were the acquisition of the vibration signals via an accelerometer fixed in the dresser holder, collected by an oscilloscope and dresser wear measurements using a microscope. Through spectral analysis of vibration signal in three conditions of use, and, new, half-life and worn, using the Welch method and Fast Fourier Transform (FFT), it was possible to identify the frequency bands between 1 kHz and 8 kHz in the amplitude increased according to the dresser wear. It has been found that the in-creased vibration activity is directly proportional to the CVD dresser wear. It was possible to identify fre-quency bands that best characterize such a situation, as in bands of 2 kHz to 4 kHz and 6 kHz and 8 kHz. The results indicate the possibility of implementing a real-time monitoring system, from the use of digital filters in these frequency bands.