A Novel Lorentz Force Sensor for Simultaneous Measurement of Defects and Motion Velocity in Nonferromagnetic Materials

In the production and manufacturing of nonferromagnetic materials, precise control of motion speed and accurate detection of defects are critical to ensuring the quality and reliability of the final product. However, existing sensors face limitations in practical applications, as they are unable to simultaneously measure the motion velocity and detect defects in nonferromagnetic thin plate materials. To address this issue, this study presents a Lorentz force sensor based on the principle of the Lorentz force particle analyzer (LFPA), which is capable of simultaneously measuring the motion velocity and micro-defects in nonferromagnetic thin plate materials. To enhance the sensor’s detection sensitivity while mitigating the effects of the permanent magnet’s weight, a detailed analysis of the influence of support beam parameters on stiffness was conducted, and the folded beam parameters were optimized through numerical simulations. Static performance tests confirmed that the sensor can accurately detect force variations on the order of micro-Newtons. Experimental testing demonstrated that the sensor is capable of detecting planar defects as small as $500~\mu $ m in 0.1-mm thick copper foil. Compared to similar sensors, this sensor can detect defects approximately 3.5% of the size of those detectable by other sensors, thereby exhibiting higher sensitivity. The design and implementation of this sensor significantly improve the accuracy and operational ease of on-site measurements in the production and manufacturing of nonferromagnetic thin plate materials, providing technical support for optimizing production processes and enhancing product quality.