Development and Testing of an On-Machine Measurement System for Shape Error of Deep-Hole Parts Based on Electromagnetic Acoustic Wall Thickness Method

Precision deep-hole parts are extensively utilized across various sectors of industrial production, and their machining quality exerts a significant influence on numerous variables, such as fatigue limits, geometric precision, and product stability. On-machine measurement is a critical method to assess geometric features and guide the subsequent processing stage. This technique boasts substantial benefits, including immediacy, interactive capabilities, and widespread recognition within the metrology domain, particularly for the assessment of large-scale parts. As a crucial metric for appraising the machining quality of deep-hole parts, the measurement of roundness and axis straightness errors is paramount in ensuring the functional integrity of deep-hole products. Utilizing the wall thickness method, a multisensor integrated measurement system for these two categories of shape errors has been developed. This system employs an electromagnetic acoustic transducer (EMAT), an eddy current sensor, a laser interferometer, and a rotary encoder. Pertinent to this system, an uncertainty analysis model for roundness and axis straightness errors is devised. The effectiveness of the measurement system is verified by experiments.