An Investigation of Eddy-Current Effects on Parameter Monitoring for Duplex Lathe Machining of Thin-Wall Components

This paper presents a novel design of an eddy-current sensing system with an array of high-accuracy solid magnetic sensors for duplex lathe machining of thin-wall compressor disks. By controlling the penetration depth of the eddy current, the dual-frequency sensing system based on measured magnetic flux density simultaneously measures the in-feed cutting depth and workpiece thickness in real-time. Specifically, this paper provides the design concept and operational principle of the eddy-current sensing system along with the theory for designing the sensor and analyzing its performance. As eddy current cannot be measured directly, results of a numerical investigation based on finite-element analyses are presented with illustrative examples offering new physical insights into the effects of optimal design parameters on the magnetic and electric field distributions of the induced eddy-current. The effectiveness of a dual-frequency eddy-current sensor has been numerically evaluated and compared against experimental data of a commercial eddy-current sensor operated at 1MHz.