Research On The Measurement Of Surface Shape And Wall-thickness Of Weak-rigidity Curved Components

The weak-rigid curved components which require high precision and wall-thickness uniformity,are typical samples in shock wave physics and detonation physics experiments.However,it is impossible to obtain measurement points on the inner and outer surfaces in the normal direction simultaneously,and the measurement accuracy of using eddy current and ultrasonic technology cannot be guaranteed.Therefore,it is very important to study key technology and basic scientific issues that are influence on the measurement accuracy of weak-rigid curved components,and verify them by experiments.A new measurement method is proposed,and various factors are analyzed and controlled.Finally,the weak-rigidity curved components are obtained by machining process and measured by the measurement method.The main research work are as follows:Based on the requirements of high precision and wall-thickness uniformity,a measurement method of the weak-rigidity curved components is proposed.Firstly,based on the curved profile and the measurement characteristics of different measurement trajectories,the meridian and concentric circular measurement trajectories are selected.The inner and outer surface are obtained with the help of high-precision coordinate measuring machine and analysis software.By analyzing the possible positional in the inner and outer surface measurement,the flange cylindrical surface is used as the measuring benchmark,and the inner and outer surface data points are unified into the same coordinate system by coordinate conversing.Based on interpolation reconstruction,the wall-thickness of corresponding points were obtained.Experiments show that the wall-thickness distribution of the weak-rigidity curved components is obtained with high precision by the wall-thickness method.The influence mechanism of different factors on the measurement accuracy are studied,and the controllable solutions are proposed.Based on the finite element simulation analysis,the adsorption flange fixture is independently developed.Compared with the original adsorption shell fixture,the deformation is reduced from the original 8 ?m to 0.6 ?m as the adsorption pressure is 50 k Pa.In order to improve the accuracy of the machining benchmark surface,traditional cutting,ultrasonic elliptical vibration cutting and "Ring Polishing of Resin Copper Disk and Ultra-Precision Onsite Cutting" machining processes are proposed,and benchmark flatness is increased from the original 4.8 ?m to 1.4 ?m,which improves the machining accuracy.The high precision weak-rigidity curved components are obtained by precision machining experiments.Adopting adsorption flange fixture,"Ring Polishing of Resin Copper Disk and Ultra-Precision Onsite Cutting" combined processing technology,etc.,effectively reduce the impact of the measurement accuracy of various factors.Then the meridian trajectories are used for measuring the weak-rigidity curved components.The result shows that the surface errors of the outer and inner surfaces are about 5 ?m and 6 ?m,respectively,and the wall-thickness error is about 8 ?m without the data in the top area.