A concentricity measurement method for large forgings based on laser ranging principle

Abstract In the forging process of large forgings, the concentricity between forging billets and upsetting rod or piercing rod has an important influence on the forging accuracy and forging quality. Therefore, a concentricity measurement method based on laser ranging principle is proposed in the paper. Firstly, the distance data between the billets, piercing rod and the laser rangefinders is obtained using two pulse laser rangefinders with a measurement resolution of 1 mm. Secondly, the improved Kalman filtering method is proposed to process the distance data to weaken the influence of random noise on the measurement results. Finally, the weighted least square fitting method is employed to analyze the geometric centers of the workpieces, and then the concentricity is calculated using the obtained geometric centers. The experimental analysis results indicate that the measurement error of concentricity is less than 0.5 mm. The proposed concentricity measurement method is suitable for measuring concentricity in forging and piercing, which can improve the operation precision of upsetting or piercing.