Research On The Factors Influencing Measurement Accuracy In The Dimension Measurement System Based On The Green Laser Scanning For Hot Forgings

Large forgings is the key structure of major projects such as military, metallurgy, electric power, petroleum, chemical industry, etc. Its characteristic is big weight and size. It is mostly used for the occasion for large bearing capacity and high performance requirements. The blank is forged into the required shape and size of the forgings by the forging method. In the forging process, the dimension of hot forgings needs to be measured to ensure the required dimension measurement accuracy requirements of hot forgings. The dimension measurement system based on the green laser scanning for hot forgings has been widely used in measurement of hot large forgings. But because of the bad forging condition, the measurement accuracy is low. Then the measurement accuracy of the system is optimized in this paper. The main contents are represented as follows:Firstly, the structure and the principle of the dimension measurement system based on the green laser scanning for hot forgings are introduced. On the basis of the structure and the principle, the interaction models between the green laser and forgings is built to research the electromagnetic wave produced by the green laser stripe of the same power and the different width. Then on the premise of meeting the measurement accuracy, the optimal width of the green laser stripe is chosen to make the green laser stripe clearer on hot forgings. And the measurement accuracy is improved.Secondly, the filter system is designed based on multiple-stage acousto-optic tunable filter. In the filter system, a computational model is built by combining the visible radiation character of hot forgings and the threshold power density of CCD saturation under different temperatures. The curve of the filtering rate of bright light can be obtained using the computational model. In order to realize the goal of intelligent filter, each stage of the acousto-optic tunable filter is adjusted according to the curve of the filtering rate. Then the factors of the visible radiation light and CCD are removed.Finally, the experimental verification is conducted based on the experimental system designed by us. The optimal width of the green laser stripe and the filter system are applied to the experimental system. The hot forgings is measured, and the measurement data are recorded. The measurement accuracy of the experimental result is calculated. The validity and feasibility of the theory is verified.