Flexible in-line measurement technology for surface defects of small bores

To fulfill the need of measurement on the small bore's interior features, a specially designed optical transmission component is adopted to divert exterior illumination into the interior of small bore and to export the interior image. This study has surpassed the traditional mode and achieved the exterior placement of the measurement sensors to make it possible for the measurement in narrow space. To fulfill the need of measurement on small bores in different position and direction, a new flexible in-line measurement system is set up utilizing the movement platform of industrial robots. Firstly, the design of the measurement system is proposed based on analysis of the preliminary method, and the flow of the work is given. Then, the question of alignment between sensor and sample is analyzed in detail, and a novel, reasonable method of aligning is given. Based on the aligned system, the measuring experiment is carried out on 0.6 mm, 1.0 mm and 2.0 mm simulated defects on interior wall of 10 mm diameter bore, and the standard deviation is almost less than 0.01 mm. The experimental results show that the system is valid and able to accomplish the feasible, on-line measurement.