Study On On-Line Tool Condition Monitoring In Rotor Slot Milling

Turbine rotor is one of the key components of thermal power generation unit, its fir-tree slot has very complicated contour line, its form- milling requires massive machining time, and the milling cutters are prone to wear and breakage. Operators have to keep focused on the cutting process to prevent the quality problems such as out of tolerance and surface burning from happening due to tool failures during the milling processes. So the research of on-line monitoring system for the cutting tool as well as cutting process has an economic and practical significance for the relief of working pressure for the operators and the improvement of product quality.This dissertation utilizes three indirect sensore: temperature, noise and power to on-line monitor the condition of tools and the machining process. The virtual instrument software development tools LabVIEW (Laboratory Virtual Instrument Engineering Workbench) is selected as a platform for the monitoring system. The monitoring software is composed of three main modules: data collection and storage, data analysis, data calibration and overrun alarm; it can achieve function of real-time collecting, signal processing and real-time display for cutting temperature, noise and power. Digital filtering technology, FFT and Wavelet Analysis are utilized in the data analysis module. The impact of different main spindle speed, feed power and radial depth of cut on the tools wear condition has been explored through the wear experiment of machining slot with wave milling cutter of same helix angle..The milling experiments were carried out both in the laboratory and turbine workshop. The correlations among monitoring indice ,cutting tool and cutting parameters have been investigated with experiments It was found that the identification of tool wear is possible based on the monitoring indice.