Abstract: In the high-speed milling process of aircraft structural parts, the different machining processes and clamping methods will lead to different residual stress releases, and the processing deformation of the final parts will also be different. Therefore, the analysis of the stress relief mechanism and the prediction of process deformation of aircraft structural parts in multi-process processing are the core links and basis for processing quality control. Firstly, the residual stress which would affect the machining deformation should be considered, the mechanical model and finite element analysis method of machining deformation are established, and the experimental results show that the calculated value of the model of machining deformation is very consistent with the experimental value, and the maximum error is not more than 9%;Then, by defining the process margin, total process margin, and total machining margin, a recursive calculation model for process deformation is established, revealing that the final machining deformation of aircraft structural components is only related to the last process and key machining steps. Finally, the optimization model of the total operation margin of the key processing steps and its step decreasing algorithm are proposed, and the process optimization is carried out on the multi-process machining process of the typical three-frame structural parts, and the results show that the optimized process can reduce the machining deformation of three-frame structural parts by about 99%.

Key words: aircraft aeronautical monolithic component, residual stress, machining scheme, total process allowance, step reduction algorithm