On-Line Measuring Method Of Outline Dimension For Hot Ring Forgings

Ring forgings are widely used in railway,construction machinery,bearings,ships,petrochemical industry,power generation,aerospace,nuclear industry and other industries.In the dynamic forging process of ring forgings,the on-line measurement of radial section line and dimension data plays an important role in controlling its dimension accuracy and reducing scrap rate.However,the ring forgings are in the dynamic process of high temperature and high speed rotation.Moreover,the scanning angle of the laser scanner is limited.Therefore,it is necessary to scan the ring forgings several times.Because of the large amount of scanning data caused by multiple scanning,the accuracy of radial dimension measured by this method is low.Therefore,it is of great significance to improve the on-line measurement accuracy of radial section dimension and ensure the production quality of ring forgings.In this paper,the method of on-line measurement of the outline dimension for hot ring forgings is studied.The specific research contents are as follows:Firstly,the arc segments of data obtained from multiple scans are spliced.The laser scanning data is described as a topological space form with reference to the repeated parts of laser scanning data after splicing.The topological transitivity between the original information space and its double inverse limit space is used and the concept of information gain rate is combined.By researching the discrete curvature of each point and the distance between two points,the position of one unknown part point of the section line can be uniquely determined.A complete radial section line of ring forging can be obtained by repeated operation.Secondly,an information space set is established for the complete radial section data.Next,the information space is divided by continuous concentric circles.According to the information relationship among regions in the information space,the uniform isomorphism factor is defined.The gradient descent method is used to solve the undetermined coefficients.The reduction ratio is set according to the data density of the section line.Through the combination of reduction ratio and undetermined coefficients,the number of points needed to be reserved for each part of the concentric circle is determined.The remaining points and the repeated points of the intersection part of two concentric circles are deleted.The method is repeated to traverse the section data to process the radial section data of the ring forging.This makes the radial section dimension extracted from the section line have higher accuracy.Finally,the experimental system of ring forging dimension measurement is built in laboratory.The standard ring forging and non-standard ring forging were used as experimental objects.The processed radial section line of ring forging is obtained.The measured values of the radial dimension of the ring forging are extracted from the section line.The measured values obtained by direct measurement of ring forging with caliper are taken as the real value for comparison.Through this way,the on-line measurement method of the hot ring forging dimension proposed in this paper can meet the industrial requirements of the measurement accuracy to be verified.