Abstract:The development background and technical characteristics of in-space manufacturing technologies are analyzed in this paper. Some research progresses in in-space additive manufacturing and welding technologies are introduced， and the research hotspots in related fields are summarized. It includes the development status of in-space additive manufacturing technologies and equipments of nonmetal and metal materials， and the research progress of in-space welding technologies and equipments， such as electron beam welding， solid state welding and so on. The developing direction of in-space manufacturing technology in China is discussed. The research results can provide reference for the future research and development of in-space manufacturing technology in China.

Abstract:This article introduces the working environment and manufacturing characteristics of liquid rocket engine in the aerospace field， and analyzes the principle of additive manufacturing technology and its advantages in corresponding manufacturing field.It also summarizes the latest situation of domestic and foreign aerospace additive manufacturing technology application. Combined the engineering application examples of liquid rocket engine， the application development of additive manufacturing engineering has undergone a systematic analysis of the four stages of engineering applications refer to replacing traditional processes，integrated manufacturing，lightweight manufacturing and systematic integration design. And points out the existing solutions and problems in the process of engineering application advancement of liquid power additive manufacturing technology.It puts forward corresponding development suggestions for the promotion of additive manufacturing industrialization finally.

Abstract:This paper reviews the latest domestic and overseas developments in the manufacturing process of millimeter-wave and submillimeter-wave waveguide components， and classifies and elaborates the most adopted processes， including machining improvement and CNC ultra-precision process， electro-chemical process， micro-electro -mechanical system （MEMS） process， high energy beam process， and 3D additive manufacturing process. The typical results of the latest progress in the application of the processes are introduced， and the advantages and limitations of the process methods are discussed. According to the application requirements of waveguide products， the trend of the process research and development is analyzed. Combining the application scenarios and the future development trend of millimeter-wave and submillimeter-wave waveguide products， the possible future development direction of each classified process in this field is proposed.

Abstract:This paper used the finite elements method to establish two-dimensional axisymmetric thermo-mechanical coupling model in friction pull plug welding （FPPW）. The results show that temperature rising rate of the interface in the initial stage was higher than that in the quasi-steady stage， because of the loss of friction heat to external environment. The temperature of the plate was higher than that on the plug side and the friction heat concentrated on the plug easily. Due to the decrease of strength and deformation resistance with the increase of temperature and strain， the interface and flash of upper wall was formed preferentially. The material flow of the lower wall occurred when the material was fully softened. After the welding process reached the quasi-steady state， the stress of the interface was distributed as the compressive stress on the central and tensile stress on the side， which derived the forming of flash on the plate. The simulation results agree with the actual welds.

Abstract:In order to increase the hole filling of large-area copper overlaid in multilayer PCB in model products， in this study， a three-dimensional model of four-layer large-area copper-clad through-hole soldering was established. By studying the temperature field distribution during the through-hole soldering process of a four-layer copper-clad printed board after added temperature compensation， the influence of soldering temperature on the solder penetration was concluded. It was found that the through-hole solder penetration reached 100% at the soldering temperature of 350 ℃， which is consistent with the actual soldering result that all solder joints reached 100% solder penetration. The finite element temperature simulation results are in good agreement with the thermocouple temperature measurement results， indicating that the model can accurately simulate the temperature evolution during the soldering process， and provides theoretical guidance for the manual soldering process and soldering parameter optimization of large-area copper-clad through-hole solder joints. It has very important research significance for ensuring the solder penetration rate of the through-hole solder joints， and then ensuring the production quality of the products.

Abstract:In the conformal phased array radar， the flexible surface T/R module based on LCP substrate was studied in order to solve the problems such as the mismatching between components and the antenna plane and the system instability caused by the increase of plug and unplug of cable connection. The LCP laminating quality control and the chip embedding was investigated. The assembly stress on LCP multi-layer substrate was analyzed with ANSYS. The results show that optimized lamination process with auxiliary material makes the substrate flat without cavity inside. The air tightness of LCP substrate embedded with MMIC is 7.4×10^-7 Pa·m³/s. The simulation results show that the stress increases rapidly between temperature of -55 and 80 degree centigrade when the LCP substrate’s bending angle is greater than 10 degrees. The conformal T/R module remains well performance with LCP substrate bending 10 degrees. The LCP substrate has a good potential in conformal phased array.

Abstract:In order to strengthen the application foundation of domestic M55J carbon fiber in aerospace components， the interfacial properties of domestic M55J carbon fiber， aerospace epoxy resin and cyanate ester resin were significantly investigated， and compared with the import M55J carbon fiber. The surface morphology of carbon fiber was characterized by using scanning electron microscope and atomic force microscope. Furthermore， work of adhesion， wettability， chemical reaction characteristics and interfacial shear strength were examined by contact angle method， infrared spectroscopy and micro debonding test. The results show that there are a lot of grooves and a spot of sizing agent protuberance on the surface of domestic M55J carbon fiber. The wettability of domestic M55J carbon fiber with two kinds of aerospace resin is more superior than that of imported M55J carbon fiber， and the adhesion work between domestic M55J carbon fiber and two kinds of resin are 55.76 and 48.61 mN/m， respectively， which are higher than that of imported M55J carbon fiber. The extent of reaction of domestic M55J carbon fiber sizing agent with two kinds of aerospace resin can reach up to 100% after high-temperature curing. The interfacial shear strengths of domestic M55J carbon fiber and two kinds of aerospace resin are 74.62 and 62.99 MPa， respectively， which are higher thanc that of M55J carbon fiber.

Abstract:In order to solve the basic scientific problems during the hot-press process of 300 ℃ resistant polyimide composites and promote application of polyimide composites in the main load bearing structures of weapons equipment， the chemical reaction properties of 300 ℃ resistant polyimide resin and the mechanical properties of the corresponding composites were analyzed by DSC、FTIR、rheology、TGA and mechanical properties test. The experiment results show that the polyimide resin is fully imidized at 230℃，the minimum viscosity of the polyimide resin is 86 Pa.s at the heating rate of 1℃/min， the corresponding polyimide composites produced by the optimized molding process exhibit good internal quality and mechanical properties.

Abstract:Turbine spherical shell is a key component of liquid rocket launching power，which affects the success or failure of rocket launch.However，the performance of the turbine spherical shell produced by the traditional free forging process has not been able to meet the design requirements.Based on the use of die forging process to form the turbine spherical shell in this paper， by simulating the microstructure of GH4061 and the forming process of the turbine spherical shell，the optimal forming temperature and critical deformation parameter law of GH4061 alloy， the forming process of the turbine spherical shell and strain distribution characteristics are systematically studied.The results show that the optimal forming temperature of GH4061 alloy is 1 000 ℃，and the optimal deformation is 20% to 40%. the turbine spherical shell is produced by die forging process.The blank is completely filled in the die without defects，the end face is flat，the flash is exenly distributed，and the size and performance meet the requirements of forgings.The position with the least amount of deformation during the forming process is on the lower end surface of the turbine shell，and the grain size is ASTM 5 to 6.

Abstract:In response to the demand for improving the performance of large-size 5B70 forged rings， through thermal compression simulations of the 5B70 homogenized at different temperatures and strain rates， stress and strain data were obtatined and the hot-working diagram of the alloy was fitted to guide large-size forged rings formed. The suitable processing temperature of the alloy is 400 ℃ to 450 ℃， and the most suitable deformation rate is 0.1/s. According to hot-working diagram ， the ring forging process with the same conditions was used to prepare 5B70 alloy test pieces and finished ring piece with the size of Ф2 900 mm×Ф2 600 mm×700 mm， and the microstructure and properties of the ring were studied. The results show that the 5B70 Al-Mg-Sc alloy can obtain good mechanical properties and performance of plastic deformation under the theoretical thermal deformation conditions.

Abstract:In order to solve the problems of large cutting force， fast tool wear and poor surface integrity of SiC_p/Al composites with high volume fraction of SiC in conventional machining， in this paper， the laser-induced oxidation assisted milling technology is studied for high volume SiC_p/Al materials. The loose oxide layer that is easy to remove is formed in the milling area by laser irradiation to improve the cutting performance. At the same time， the oxide layer control strategy and the milling parameter optimization process assisted by laser-induced oxidation are studied. The influence of auxiliary gas and different laser energy densities on the quality of oxide layer and the optimization of milling parameters are studied. The results show that with the increase of laser energy density， the width of heat affected zone and the depth of ablation groove increase. With the help of oxygen， it is easy to form loose and easy to remove oxide layer. The conclusion shows that with the aid of oxygen， a better oxidation effect can be obtained by selecting a higher laser energy density. With PCD diamond milling cutter， the spindle speed is 10 000 r/min and the feed rate per tooth is 7.5 μm/s can obtain the best surface quality.

Abstract:The cutting performance comparison was carried out when milling in-suit TiB_w/TiC_p reinforced titanium matrix composites at the cutting speed of 60 to 200 m/min. The results are verified on the skeleton part of the same material. The results show that the cutting speed is a factor affecting the milling temperature. When the cutting speed is in the range of 60 to 200 m/min， the milling temperature of titanium matrix composites increases with cutting speed increasing. The influence of cutting speed on milling temperature is greater than that of radial cutting width， and the influence of cutting speed and radial cutting width on surface quality is small. Based on the optimized parameters and the structural of skeleton parts， the process parameters of skeleton parts are determined， the milling parameters of rough machining are V=39.25 m/min， f_z=0.08 mm/z， a_e=12 mm， a_p=2 mm， and the milling parameters of finish machining are V=62.8 m/min， f_z=0.04 mm/z， a_e=10 mm， a_p=1 mm. Finally， the machining process optimization is verified to be reasonable and flexible.

Abstract:According to the requirements of seal bonding and working environment for valve assemblies of extravehicular activity （EVA） spacesuits，the adhesive selection and optimization，performances in typical environments， the structure design of the bonding surface of typical bonding samples and the optimization of the bonding process were carried out on three toughened epoxy adhesives HXJ-14， HYJ-51 and FHJ-75. The results show that HYJ-51 adhesive has good bonding properties， resistance to alternating temperature cycles， resistance to humidity and medium immersion， and therefore meets the sealing and bonding requirements for EVA spacesuits. For the typical valve assembly bonding， the gap between the PTFE slide and the stainless-steel valve body is designed to be 0.1 to 0.15 mm. An annular groove structure added to the bonding surface of the stainless-steel valve body， which can effectively reduce the defects of the bonding surface， avoid the formation of penetrating channels， improve the sealing reliability of the valve assembly bonding， and consequently meet the design requirements of the valve assembly.

Abstract:Welding technology has been applied in many fields. In recent years， automatic detection technology of weld defects has become an important research direction. In this paper， based on the good classification performance of vgg-16 convolutional neural network， a SC-VGG network structure is proposed， in which a single convolution layer is replaced by a composite convolution layer， and the loss function in the training process is improved， so that the network structure pays more attention to the results of prediction of weld defect type. Through the experimental test， SC-VGG network structure in the training process of loss function curve can be very good convergence. Compared with other network structure， SC-VGG network has a better weld defect feature extraction performance， the average accuracy and recall rate reached 95.86% and 98.33%， which provides algorithm support for automatic recognition of weld defects.

Abstract:For the problem of detecting oxide inclusion defects in aluminum alloy for spacecraft， the experimental research on ultrasonic detection technology was carried out.An oxide inclusion defect simulation method of aluminum alloy based on interference fit and rapid oxidation principle was used to simulate oxide defects， and the microstructure and composition of defects were analyzed.Analysis results verify the fabrication effectiveness of oxide inclusion defects. Test results show that the mechanical C-scan can distinguish defects under Φ1.2 mm effectively. For inclusion defects of about 1.2 mm equivalent，the detection effect is better than manual scanning in terms of intuition， coupling stability and repeatability.The method has been applied to the detection of oxide inclusions in spacecraft aluminum alloy products with good results.

Abstract:For the connection technologies between RF coaxial electrical connectors and microstrip circuit boards in manufacturing process of aerospace microwave components， the principles and characteristics of solder hard connection， Ω-shaped gold-plated copper band connection and gold band cladding welding were analyzed. The process control requirements and considerations of different connection technologies were proposed. The experiments， reliability evaluations and analysis of different connection technologies were carried out with electrical connectors of SMA， including qualification test， electrical properties test and thermal stress simulation. The results show that fatigue striations appear at the joints of solder hard connection after mechanical qualification test and 200 cycles of temperature cycling test， while the abnormity dose not appear in the joints of Ω-shaped gold-plated copper band connection and gold band cladding welding. The electrical properties of gold band cladding welding are similar with hard solder connection， which can meet the service demand basically in the range of 1 GHz to 8 GHz. The electrical properties of the connection of Ω-shaped gold-plated copper band have poor consistency； Maximum thermal stress of the solder joint of solder hard connection is much more than that of Ω-shaped gold-plated copper band connection and gold band cladding welding in the same temperature load， the mechanical design margin of gold-strip cladding welding is much more than that of solder hard connection.

Abstract:The properties of C/C composites with different graphitization temperatures and mixed matrix carbon were investigated by nanoindentation. The results show that the nanoindentation modulus of C/C composites with graphitization temperature of 2 500 ℃ was 10% lower than that of C/C composites with graphitization temperature of 2 300 ℃. The highest modulus of resin carbon is measured by nanoindentation in C/C composites with mixed matrix of pyrolytic carbon， resin carbon and asphalt carbon， followed by pyrolytic carbon and the lowest by asphalt carbon. The surface fracture toughness of the C/C composite micro-component was finally obtained as 0.492 MPa•m^1/2 by nonlinear fitting of the nanoindentation load displacement curve after finite element calculations.

Abstract:In order to realize the synchronous improvement of quality， flexibility and efficiency of single piece and small-batch production of spacecraft， the connotation and development of digital twin technology are reviewed， and the basic model and dynamic evolution process of digital twin technology for spacecraft manufacturing system including product twin and production line twin are proposed. The realization method of digital twin in data acquisition， synchronous modeling， system evaluation and production line reconstruction is proposed， and the concrete realization way of virtual reality interaction mechanism by digital twin is expounded， and its validity is verified by practical application of spacecraft production.

Abstract:In order to ensure riveting stability and reduce the defects caused by human operations， the research on the application of robot automatic drilling and riveting technology has been carried out in the payload fairing. The structure composition and related process research are introduced in this paper. The drilling and riveting process parameters are analyzed. The trial product of Φ3 800 mm payload fairing is manufactured. The results show that the height of the burr when drilling exit can be controlled effectively at a 12 000 r/min spindle speed and a 500 mm/min feed speed. The rivet feeding quality can be improved by controlling the process parameters such as insert depth， torque， and hovering time. The dimensions accuracy is qualified. The application of robot automatic drilling and riveting technology in the development of the launch vehicle cabin is proved to be feasible and reliable.