Long-distance Localization of 4Cr13 Stainless Ball-pocket in Radiative Region

Radiation caused by high-energy particles would speed up the damage of accelerator equipment. The high residual radiation from equipment affects staff health as well. Intelligent robots receive various limits to replace human in completing complex and time-consuming maintenance in radiative region because of high sensitivity to radiation. The 4Cr13 stainless ball-pocket was designed in the study of localization in long distance with the advantages of the conical fit technology. Moreover, the 4Cr13 stainless ball-pocket and bearing ball combine and form a locating structure, which has good performance on automatic aligning, self-locking and rapid dismantling. The comprehensive mechanical properties of 4Cr13 stainless ball-pocket were studied and optimized based on three heat treatment methods of martensite steel containing chromium alloy. The study of machining conditions states that compared with the design accuracy of localization, the machining error retains definite allowance. The 4Cr13 stainless ball-pocket successfully exhibits sufficient supporting strength, wearing reducing and radiation resistance. This study shows that 4Cr13 stainless ball-pocket has better fitting precision than 0.2 mm in practice. This study could offer a reliable strategy and measure for long-distance localization in other dangerous regions.

Experimental study on cutting factors of multi-layer machining for large aerospace thin-walled structural parts

Large aerospace thin-walled structures will produce deformation and vibration in the machining process, which will cause machining error. In this paper, a cutting experimental method based on multi-layer machining is proposed to analyze the influence of cutting tool, cutting path, and cutting parameters on machining error in order to obtain the optimal cutting variables. Firstly, aiming at the situation that the inner surface of the workpiece deviates from the design basis, the laser scanning method is used to obtain the actual shape of the inner surface, and the method of feature alignment is designed to realize the unification of the measurement coordinate system and machining coordinate system. Secondly, a series of cutting experiments are used to obtain the machining errors of wall thickness under different cutting tools, cutting paths, and cutting parameters, and the variation of machining errors is analyzed. Thirdly, a machining error prediction model is established to realize the prediction of machining error, and the multi-objective optimization method is used to optimize the cutting parameters. Finally, a machining test was carried out to validate the proposed cutting experimental method and the optimal cutting parameters.

Ultra-Precision Single-Point Diamond Turning of a Complex Sinusoidal Mesh Surface Using Machining Accuracy Active Control

Single-point diamond turning (SPDT) assisted with slow tool servo (STS) is the most commonly utilized technique in the fabrication of optical modules. However, the tool path significantly affects the quality of the machined surface. In order to realize the determined machining accuracy effectively, a tool path generation (TPG) method based on machining accuracy active control (MAAC) is presented. The relationship between tool path and machining error is studied. Corner radius compensation (CRC) and the calculation of chord error and residual error are detailed. Finally, the effectiveness of the proposed approach is verified through a machining error simulation and a cutting experiment of a complex sinusoidal mesh surface fabrication.