The advantages of electrical discharge machining (EDM) over traditional machining have earned its wide applications in industrial world. However, the low machining stability caused by the inherent characteristics of EDM, high discharge frequency, small discharge gap, and strong disturbances, has hindered its further development, especially in deep, blind hole making because of difficulty in removing debris out of the gap in deep holes, causing the occurrences of arcing pulses and damaging work-piece surface. In order to improve process stability of machining deep and blind holes and solve the issue of machining such kind of high-melting-point, difficult-to-cut materials as titanium-zirconium-molybdenum alloy (TZM), this paper has developed an adaptive double variable control system. In this control system electrode-discharge-cycle and gapservo-voltage were taken as control variables adaptively tuned, by two-step-ahead control strategy, with respect to variations of arcing ratios and discharging ratios respectively. One confirmation test demonstrated that this control system had improved machined depth of a hole more than 3.7 times from that by conventional EDM in machining Cr12MoV material. The other test confirmed that this control system helped to machine a blind hole, with a copper electrode of diameter 16mm, in the hard-tocut TZM of nearly 2640℃ melting point up to a depth of 93mm at an almost steady machining rate. The conventional EDM could hardly machine this kind of material. All these facts revealed that the developed adaptive double variable control system had endowed EDM with much stronger power to extend its applications in the newly developed materials.

Based on UV-LIGA technology, a novel passive RF coaxial transmitter was fabricated on a metal substrate by combining positive and negative photoresist. Aiming at low dimensional accuracy of thick positive photoresist AZ50XT caused by the uneven distribution of exposure dose within the resist, the method of multiple exposure and development was proposed to make high-precision electroforming mask. The effect of this method on dimensional accuracy was studied by lithography experiment of different size graphics. The experiment results show that the method of multiple exposure and development can significantly improve the dimensional accuracy of AZ50XT resist and the accuracy of the lithography pattern is no related to the mask size. Finally, based on the experiment results, a kind of passive coaxial transmitter was fabricated. The overall dimension is 3000μm×400μm×200μm, the maximum height of single layer is 60μm and the sidewall inclination of each layer is more than 85°.

The high-pressure compressor blade of aero-engine possesses compound twisted and bowed surface, small leading/trailing edge radius, difficult-to-machine material, strict design tolerance. It’s difficult to control the blade precision and surface quality with conventional forging, rolling, milling, electrochemical machining under the premise of low cost and high efficiency. Moreover, the conventional multi-axis CNC grinding suffers low efficiency and complex residual stress deformation. Therefore, this paper implements multi-spindle synchronous high-precision grinding of aero-engine blade with the reverse segmented machining method and rectangular array machine tool. By the rigidity improvement and reverse machining sequences of each segmenting part, the proposed method can ensure the datum superposition principle in the removement of flexible part local material and control the residual stress deformation perfectly. The line/surface profile error of some typical blades are fluctuant in the range of 30μm/40μm, the machining efficiency is improved by nearly 4 times. These results can not only reduce manufacturing costs of areo-engine blade greatly, but also establish the foundation for rectangular array machine tool with more spindles extension.

Most of the external tubes of aero-engines are titanium alloy bends. The inner surface defects caused by the bending process in the cold bending process are difficult to be removed by traditional grinding methods, which is a technical bottleneck. The grinding and polishing of the inner surface of the titanium alloy elbow can be achieved by the magnetic abrasive finishing. From the case of the application of the titanium alloy catheter inside the aero-engine, the basic principle of the inner surface of the magnetic grinding titanium alloy elbow is analyzed. At the same time, the key technical problems in the process of designing the grinding device is analyzed. Through theoretical anatomy and finite element simulation analysis of the magnetic field source and magnetic pole shape and trajectory design, a set of relatively complete process plans is obtained. Experimental results show that the magnetic abrasive machining method has good effect on the internal surface of the elbow defect removal.

In the design process of die cavity of investment casting, the inaccurate enlarged die cavity that based on shrinkage rate can lead the die need mold-repair for many times. As an initial study, a shrinkage rate prediction method of typical structure casting in the solidification process is proposed in this article. The method can provide a way of thinking for shrinkage rate prediction of casting. As BP neural network has strong fault tolerance and robustness function. Thus, the mapping model between geometric parameters that attach to the structure and shrinkage rate is built based on BP neural network. As there is no determination criterion for the number of the hidden layer neurons of the BP neural network in different cases, thus, the influence of the number of neurons in the hidden layer on the accuracy of modeling is researched. The result is that for the typical structure casting, when the number of neurons in the hidden layer is three, the mapping model has the least prediction error. In this case, the shrinkage rate average deviation of the predicted and measured values is 0.09%. The mapping model can better realize shrinkage rate prediction of the casting in solidification process.

The effect of grinding process on grinding affected layer is studied by using full factorial test. Considering residual stress, hardness, retained austenite, white layer and dark layer as research target, and selected grinding parameter. Meanwhile the effect of grinding parameter on grinding efficiency and grinding accuracy is considered. Experiments showed that the effect of wheel speed on residual stress, white layer and dark layer is very great. The effect of wheel speed on hardness and retained austenite is little. 9000r/min wheel speed leads to white layer and higher tensile residual stress. Best grinding parameter of grinding process is selected at last. This paper is of great significance for engineering guidance.

In this paper, the current manufacturing status of aero-engine blades is taken as the research object. We made a brief overview of ECM, CNC machining, precision forging, the key technologies and measurement methods used in manufacturing of aero-engine blades. The implementation of coordinate positioning, measurement trajectory planning and noise reduction of coordinate measurement is also considered. And then we analyze the influence of laser probe installation accuracy,laser projection angle, depth of field on laser scanning measurement, which has certain guiding significance to the development of precision manufacturing and efficient testing technology of aero-engine blades.

In this paper, the current manufacturing status of aero-engine blades is taken as the research object. We made a brief overview of ECM, CNC machining, precision forging, the key technologies and measurement methods used in manufacturing of aero-engine blades. The implementation of coordinate positioning, measurement trajectory planning and noise reduction of coordinate measurement is also considered. And then we analyze the influence of laser probe installation accuracy, laser projection angle, depth of field on laser scanning measurement, which has certain guiding significance to the development of precision manufacturing and efficient testing technology of aero-engine blades.

Aiming at the problem of low automation and low efficiency of traditional aircraft assembly line, a modular flexible aircraft assembly line is designed. Plan the traditional parts assembly line and general assembly line as an assembly line. Modularize the general assembly area, the component assembly area and the parts assembly area according to the assembly process and the nearly layout principle. Design of assembly tooling, hole equipment and working platform of assembly line is modular. Set up common mobile interface and energy information interface. Through the analysis of the efficiency of the aircraft assembly line, it is concluded that: On the basis of not increase the construction cost significantly, the equipment utilization rate of the modular flexible aircraft assembly line has been greatly improved, the overall automation degree has been significantly improved, and the assembly cycle has been significantly shortened.

The structure and size of the focusing parts will directly determine the current density and radius of the electron beam. They will also affect the quality of the electron beam. By using CST simulation software to analyze the focusing parts of electron beam guns, the effects of different structural dimension parameters on electron beam current density and beam radius are obtained. The simulation results show that when the other parameters are unchanged, the beam radius decreases from 1.44mm to 0.93mm with the distance between the upper surface of the focusing coil and the surface of electron emitting increasing from 305mm to 345mm. When the radius of the focusing coil increases from 30mm to 40mm, the beam radius increases from 0.86mm to 1.38mm. When the gap of magnetic yoke increases from 28mm to 43mm, the beam radius firstly decreases and then increases. The beam radius reaches a minimum point at 0.957mm when the gap of magnetic yoke is 34mm. We take welding test on 1mm TC4 thin-wall plate with the electron beam gun whose focusing parts has optimized by CST simulation. In the same welding process parameters, the width of weld seam by using optimized electron beam gun is lesser than that by original electron beam gun.

As one of the key performances of infrared guidance devices, it’s of great significance to carry out innovative research on the intelligent design method of environmental adaptability. The development and present situation of MBSE and AI are briefly introduced. The intelligent design method is analyzed and five models are established by SysML, such as one intelligent design system architecture model with five levels, one reasoning process model consisting of several intelligent algorithms, one object-oriented structure model of knowledge and one activity model for extracting knowledge form the cases database using FNN approach. A useful reference for I2CAD system of precise guiding devices is provided by the research.

The difference of organization in different location of the ZTC4 electron beam welding joint was discussed through the microscopic hardness test, metallographic analysis and conventional mechanical property test. The correlation between microscopic hardness and microstructure of EBW joint and the tensile and impact performance of EBW joint were also studied. Study found that the microstructure of ZTC4 EB weld changed from original β to acicular α’, and the microstructure of HAZ was composed of a mixture of flaky α and original β. The microscopic hardness of EBW joint was higher than base metal and HAZ, and tensile and impact performance of EBW joint were equivalent to the base metal. By studying the difference of performance characteristics between ZTC4 EBW joint and base metal, the foundation of research was provided for ZTC4 EBW application, and the wider and wider application in aerospace industry was promoted for large-scale titanium alloy casting and welding structure.

Experimental and numerical methods were employed to study deformation mechanism and elastic properties of the plain woven SiO_2f/SiO₂ composite which was prepared by conventional sol-gel process. Firstly, the elastic modulus along the fiber direction was measured experimentally; Secondly, the representative volume element (RVE) method was used to set up the cell model in ABAQUS software. Equivalent elastic modulus of the material was obtained based on periodical boundary condition, and was compared with experiment data to verify the reliability of numerical method. Finally,the nine equivalent elastic constants of SiO_2f/SiO₂ composites were calculated based on FEM analysis results, including Young’s modulus, shear modulus and Poisson ratio. The conclusions can be drawn that the RVE method based on boundary condition can solve the deformation compatibility of RVE method, and be used to predict the elastic property of material and deformation behavior. The prediction equivalent elastic constants agree with the test result and can contribute to structure design and optimization of the advanced SiO2f/SiO2 composites.

The quality of aircraft skin subsidence has great influence on the overall weight of aircraft, and plays an important role in maintaining the appearance of the surface. In the manufacture of modern aircraft skins, the accuracy of the aircraft skin subsidence is also raised. In this paper, a method of extracting the feature points of the skin subsidence based on T-Scan measurement is proposed in order to achieve the purpose of digital detection of the plane subsidence characteristics of the aircraft. Firstly, scanning lines are identificated from point clouds, and the 3D point cloud data is reduced to two dimensional data. Subsequently, the first and last derivatives of each point are computed by first order difference, the sag points are extracted by judging the vector angle, and the the boundary points are found by comparing the curvature of the sag points; Finally, the boundary points are projected to the line, which is fitted with data points on upper surface, projection points will be obtained as feature points of skin sag. The method directly deals with the scan line cloud data obtained by T-Scan scanning; Through the measurement and processing of actual aircraft skin, the experiment shows that the method has good practicability, the extraction precision of sag feature points is higher.