An inspection technology of inner surface of the fine hole based on machine vision
This addresses quality control for industrial components with fine holes, representing an incremental improvement in inspection technology.
The paper tackled the problem of inspecting inner surface quality of fine holes in industrial components by developing a machine vision-based optical measurement system, achieving a maximum measurement error standard deviation of about 10μm for defects as small as φ0.1mm in holes with a minimum diameter of 4mm and depth up to 47mm.
Fine holes are an important structural component of industrial components, and their inner surface quality is closely related to their function.In order to detect the quality of the inner surface of the fine hole,a special optical measurement system was investigated in this paper. A sight pipe is employed to guide the external illumination light into the fine hole and output the relevant images simultaneously. A flexible light array is introduced to suit the narrow space, and the effective field of view is analyzed. Besides, the arc surface projection error and manufacturing assembly error of the device are analyzed, then compensated or ignored if small enough. In the test of prefabricated circular defects with the diameter φ0.1mm, φ0.2mm, 0.4mm distance distribution and the fissure defects with the width 0.3mm, the maximum measurement error standard deviation are all about 10μm. The minimum diameter of the measured fine hole is 4mm and the depth can reach 47mm.