Online monitoring device of disc cutter wear – Design and field test

Abstract The disc cutter is the main rock cutting tool of a tunnel boring machine (TBM), and its wear directly affects the cutter change decision. Therefore, real-time monitoring of disc cutter wear has become an urgent technical problem for boring machines. In this study, an online monitoring system based on an eddy current sensor is designed to monitor disc cutter wear in real time. The effects of three types of rock and muddy water mixture on the measurement data are compared. Results show that measuring the eddy current distance can solve the problem of inaccurate measurement after the disc cutter is covered by rocks. Besides, the error data of this method in measuring disc cutter wear are analyzed. A function test is performed for similar disc cutters on a multi-function disc cutter performance test bench, and a real-time continuous test is conducted for the wear of two disc cutters in a certain TBM project. With a comparison of monitored and measured results, it shows that the error is less than 1 mm, which indicates that the system exhibits stable transmission and high accuracy in measurement and meets engineering requirements.