On-machine high accuracy radial wear characterization of rotating milling tools using a camera-based system

In precision machining operations, surface quality and dimensional accuracy are critical for ensuring part conformity to specifications and improving economic productivity. Over time, tool degradation can result in dimensional inaccuracies, poor surface finishes, and even catastrophic failures, thereby impacting the overall production performance. Therefore, high-resolution on-machine tool wear measurement is essential for optimising manufacturing processes, maintaining product quality, and enhancing productivity. Tool condition can be monitored indirectly using multiple sensors; however, it cannot explicitly quantify the amount of wear on the cutting edge. Thus, imaging based optical systems can access the current state of the machined surface and regarded as quantitative indictors of tool wear. This paper introduces a new on-machine camera based system enabling fast and automated high-resolution characterization of wear of milling tools. The optical system gives a digital representation of the profile of the cutting edges and allows the fast assessment of the wear distribution along the entire axial length of each individual cutting edge of the rotating milling tool. The paper further describes the characterization of the metrological performance of the instrument by comparing the measured radial wear with reference measurements using confocal microscope images. Results have demonstrated that the camera based system can correctly measure the local radial wear (in sub micrometer range) on the cutting edge of side milling tools with performance coherent with the requirements of tool wear monitoring in fine finishing milling operations and is suitable for industrially viable on-machine high resolution tool wear monitoring. • A new on-machine camera based system for fast and automated high resolution characterization of wear of milling tools. The optical system determines the radial wear which can be correlated with the flank wear VB • The system provides sub-micron resolution to create a digital model of the milling tool and achieves 6 µm resolution and the high data density in the axial direction. Digital representation of the profile of the cutting edges and fast assessment of wear distribution along the entire axial length of each individual cutting edge of the rotating tool, obtained from on-machine measurements • The camera based system shows the capability of the instrument for fine finishing operations where the engagement arc is small, and a high resolution (small axial intervals) for detecting changes in the wear zone and wear measurement is needed • The validation process resides on a combination of calibrated confocal imaging (reference measurement), SEM imaging and EDX. Task specific uncertainty evaluation of the measurement process of determining the radial wear. The instrument is consistent with industrial needs and suitable for industrially viable on-machine tool wear monitoring due to short measurement time and high measurement accuracy