Envelope dynamic analysis: a new approach for milling process monitoring

Vibration analysis has long been used for the detection and identification of the condition of machine tools. This paper proposes a method for vibration analysis in order to monitor online the milling process quality based on synchronous envelope analysis. Adapting envelope spectral analysis to characterize the milling tool is an important contribution for qualitative and quantitative characterization of milling capacity. It is a stage in modeling the three-dimensional cutting process. To determine different parameters, to understand the phenomenon which takes place during the cutting process, and to validate the monitoring algorithm, it was necessary to build and to use a complex analysis system. An experimental protocol was designed and developed for the acquisition, processing, and analyzing the three-dimensional signal. The vibration envelope analysis is proposed to detect the cutting capacity of the tool with the optimization application of cutting parameters. This purpose is reached by a detailed dynamic study of the manufacturing system divided into two parts. The first one concerns the complete analysis of the machine, of the main spindle. A dynamic analysis method is developed to completely characterize the various components of machine tools. The second is concentrated on the cutting process to condition monitoring and diagnosis. The research is focused on fast Fourier transform optimization of vibration analysis and vibration synchronous envelope to evaluate the dynamic behavior of the machine/tool/workpiece.