Cylindricality Error Analysis Of Deep Hole Based On Ultrasonic Testing

With the development of industry and manufacturing industry,deep hole parts are widely used in aerospace,navigation,power and other large equipment fields.Due to various factors in the processing,these parts will produce errors relative to the ideal elements.Such errors may affect the function of mechanical products.Therefore,after processing,the parts should be measured to judge the influence of errors on the products,so as to determine whether the parts are qualified or not.Cylindricity error is also one of the 14 common geometric tolerances.For the deep and small holes processed on the parts,especially when the diameter of the deep and small holes is below 1mm and the depthdiameter ratio exceeds 10 : 1,due to the limitation of the internal space of the deep and small holes,the accessibility of the detection equipment is poor and cannot be directly measured.Therefore,the detection of cylindricity error of deep and small holes with large depth-diameter ratio is more difficult,and the measurement level is lower than other geometric errors.Therefore,this paper has done the following research on deep holes with large aspect ratio :(1)With the help of D70 series high-speed EDM machine,a hole with a diameter of1 mm is machined along the axis direction in the optical axis of 304 stainless steel,and the calibration of the measuring point is completed on the outer surface of the workpiece with deep holes by means of the dividing head.(2)Aiming at the difficulty of detecting deep holes with a depth-to-diameter ratio of more than 10 : 1,an ultrasonic detection platform was built.The ultrasonic detection platform is mainly composed of ultrasonic pulse generator receiver,oscilloscope,sensor probe and PC terminal,which completes the data acquisition and data storage of the workpiece to be tested.(3)By referring to the existing research content and combining with the geometric technical specifications,the mathematical model of cylindricity error is established,and the mathematical model of coordinate transformation is established.The sound path data obtained by the ultrasonic testing equipment is transformed into the coordinate data that can be calculated.After being imported into MATLAB,the cylindricity error values corresponding to the maximum inscribed cylinder method,the minimum circumscribed cylinder method,the least square method and the minimum region method are calculated by using the cylindricity error evaluation model optimized by genetic algorithm.(4)In order to realize the visualization requirements of the cylindricity error of deep holes,with the help of image processing technology in MATLAB,the optimal solution is searched in the space near the deep hole by genetic algorithm,and the axis of the optimal solution is determined by the axis of the optimal solution,that is,a,b,u,q parameter values.The axis of the ideal cylinder corresponding to each evaluation method is determined,and then the ideal cylinder radius is confirmed by the mathematical model of the evaluation method.Finally,the surf command in MATLAB is used to complete the drawing of the ideal cylinder surface,and the visualization requirements of the evaluation method can be completed.Figure 44 Table 12 Reference 80...