Selective melting is a powder bed based metal additive manufacturing processes, and capable of manufac-turing components with complex shapes and manipulating the material micro-structures and properties locally and globally. Computational modeling of the manufacturing processes provides valuable instructions to advance the technologies. This paper introduces the research progress in this regard. Firstly, the principle and characteristics of laser/electron beam selec-tive melting are introduced. The state-of-the-art of numerical modeling of the manufacturing processes is summarized. The multi-scale multi-physics models for electron beam selective melting will be presented in detail, which consist of (1) a mi-cro-scale electron-material interaction model; (2) meso-scale models of powder particles from being spread to being heated, melted and solidified; (3) a macro-scale model of part fabrication process.

Only 2 cases that the aircraft parts made by metal additive manufacturing have been authenticated by profes-sional authority worldwide. On the contrary, additive manufacturing parts made by polymer additive manufacturing have been used about 20 years long formally by Boeing Airplane, the cumulative total of more than 100000 units. Deeply integrating the additive manufacturing technology and aviation industry, making overall planning and do the top-level design well, attaching equal importance to both polymer and metal additive manufacturing technology to make aircraft parts directly, these are the key point to promote healthy and sustainable development of additive manufacturing industry .

In order to reduce the deformation of complex structural parts caused by NC machining, and to meet the requirement of adaptive adjustment of fixtures, an adaptive control method is proposed based on the machining principle of floating fixture. The floating fixture units communicate with each other by CAN (Controller Area Network) bus. Part condi-tion monitoring method based on multiple sensors is developed, machine tool condition is monitored based on OPC tech-nology, the floating fixtures and CNC machine tool interact based on PLC. The floating clamping adaptive control system is developed. The adaptive control system for floating fixtures has been verified in the aviation manufacturing enterprise during the machining of aircraft structural parts, the control system can realize the adaptive adjustment of floating clamping and meet the industrial application requirement.

 

 Concerning the difficulties such as large errors and low efficiency in traditional detection method of the skin seam and the defects based on 2D laser scanning, a method of the skin seam based on 3D laser scanning is proposed and corresponding software is developed. Methods and steps of de-noising, critical points recognition and extraction for the skin seam testing based on 3D point cloud are proposed. Based on the influence of gap and flush on the aerodynamic shape, the actual geometry structures are analyzed. Compared with theoretical structures, the mathematical model of gap and flush is established. The calculate accuracy is verified through experiments of simulation work piece. Field experiments show that the detection method is feasible and compared with two-dimensional laser detection, the accuracy and repeatability are better. The gap measurement accuracy reaches 0.04mm as well as the flush measurement accuracy reaches 0.02mm, which meet the needs of the skin seam detection and provid the numerical basis for the analysis of the influence of gap and flush on the assembly quality.