In order to improve the joint strength of traditional mechanical crimping terminal and wire, while decreasing the resistance, the electromagnetic pulse crimping process of DTM–50 terminal and wire was studied, focusing on the assessment of mechanical properties, electrical properties, cross section morphology and other indicators. The results show that with the increase of discharge voltage, the radial deformation and pullout force of the electromagnetic pulse crimped joint increase, and the resistance of the joint decreases, and the variation trend tends to be stable with the internal gap filling gradually. Based on the performance of traditional mechanical crimping joint, the discharge voltage process window of electromagnetic pulse crimping is 8–10 kV, and the corresponding discharge energy is 9.73–15.20 kJ. Among them, 9 kV is the optimal process parameter, and the pullout force of electromagnetic pulse crimping is increased by 150% than conventional process, and the contact resistance is decreased by 50% than conventional one.

To address the impact of modeling errors and unknown external disturbances on the trajectory tracking accuracy of robotic arm systems in practical applications, an adaptive non-singular fast terminal sliding mode control strategy based on a nonlinear disturbance observer (ANFTSMC-DO) is designed. First, a nonlinear disturbance observer is devised to estimate disturbance information online. By selecting an appropriate nonlinear gain function, the estimation error converges rapidly in an exponential manner. Next, an adaptive non-singular fast terminal sliding mode controller is employed to handle parameter variations and unmodeled dynamics, preventing system performance degradation over time. Meanwhile, under the premise of ensuring robust stability and control accuracy, the proposed method effectively suppresses chattering, thereby enhancing resistance to external disturbances. Finally, simulations verify the effectiveness of the proposed method.

To enhance the milling quality of aircraft skin and meet the precision requirements for butt joint gaps during assembly, we propose a method for extracting the milling auxiliary line of aircraft skin based on multi-feature selection. Initially, the collected point cloud data undergoes preprocessing through bilateral filtering. Following this, a hierarchical search structure that combines multiple point cloud features is employed to search for boundary points. The spatial tangent continuity feature is applied to extract the primary part of the point cloud boundary points. Subsequently, an optimized local surface standard deviation feature is utilized to search for the remaining points, and the results are merged to obtain the complete set of boundary points. Finally, an anisotropic optimization algorithm is applied to contract the scattered boundary points into linear shapes. Experimental results indicate that the precision of the detected boundary points can reach 0.95, with an error margin of less than 0.3 mm. When processing the skin workpiece by using the boundary points obtained by the method in this paper as auxiliary lines, the average value of the butt joint gap after splicing is less than 0.4 mm.

The integral blisk is a key component in enabling the new generation of aircraft engines to achieve structural innovation and a technological leap. Its profile accuracy and surface quality have a significant impact on the fatigue and aerodynamic performance of the aircraft engine. Currently, the integral blisk grinding and polishing process in China remains in a backward stage, characterized by manual polishing, which results in poor blade surface quality, inconsistent performance, high labor intensity and low efficiency. This paper introduces the robot belt grinding and polishing equipment for integral blisks and its technical principle, and uses this equipment to carry out the process testing of the titanium alloy integral blisk. Based on the structural characteristics of the integral blisk and the experience of manual polishing methods, this paper proposes an automated polishing process method for integral blisk, including polishing trajectory planning, optimization of grinding tools and processing parameters, and realizes its application in the processing of integral blisk through process control and parameter feedback adjustment. The results show that the surface roughness R_a of the integral blisk after robot polishing is less than 0.4 μm, the grinding and polishing efficiency is significantly improved, and the consistency of the grinding and polishing profile is also enhanced remarkably. The material removal amount of the blades during polishing is 0.008–0.013 mm, and the blade profile tolerance meets the design requirements.

To investigate the material removal behavior and surface integrity of robotic belt grinding for titanium alloy hollow components fabricated by additive manufacturing, experiments were designed and conducted. The effects of robotic belt grinding on the surface material removal characteristics, abrasive debris, surface morphology, and subsurface material of titanium alloy hollow components fabricated by additive manufacturing under different constant grinding force conditions were comparatively investigated. The results show that when the grinding force is reduced from 25 N to 10 N, surface roughness was reduced from Ra 2.11 μm and Ry 16.5 μm to Ra 1.03 μm and Ry 8 μm, the thickness of the slip layer is reduced from 55 μm to 45 μm, and the residual compressive stress on the surface is reduced from 243 MPa to 89 MPa. The robotic belt grinding experiments show that a smaller constant grinding force can improve the surface processing quality, reduce the surface roughness and damage, and decrease the depth of slip deformation and residual compressive stress of the subsurface material, thus improving the machining performance of the titanium alloy hollow components fabricated by additive manufacturing. It is expected that this study will provide a theoretical basis and technical reference for research on robotic belt grinding of titanium alloy parts fabricated by additive manufacturing and their surface integrity.

To investigate the effect of process parameter variations on grain orientation evolution and surface topography of Ti–6Al–4V (TC4) grinding surfaces, orthogonal grinding experiments were performed on TC4 specimens. The surface roughness and topography were subsequently measured using SEM and an optical profilometer. The Taylor factor corresponding to the grain orientations of each specimen group was calculated via the Taylor factor model. Subsequently, the mapping relationships among process parameters, grain orientation evolution, surface roughness, and surface topography were analyzed. The results show that surface roughness was positively correlated with the Taylor factor, grinding depth, and feed speed, while negatively correlated with the grinding wheel speed. Grinding depth exhibited the most significant influence on surface roughness, followed by feed speed and grinding wheel speed. Reducing the Taylor factor, grinding depth, and feed speed while increasing the grinding wheel speed can effectively prevent brittle deformation during surface formation, thereby improving grinding surface quality while balancing machining efficiency. The findings of this study provide theoretical guidance for controlling grinding surface quality and optimizing machining processes.

The effect of diffusion welding process parameters on the microstructure, mechanical properties and deformation of Ti₂AlNb alloy welded joints was studied. The results show that when the welding temperature, pressure, and holding time are low, the weld line of Ti₂AlNb diffusion welding joint is distinct, and the mechanical properties are inferior. With the increase of welding temperature, pressure, and holding time, the size of the newly formed equiaxed α₂ phase in the welding zone enlarges, the weld line gradually becomes indistinct, and the mechanical properties, the welding deformation rate of the Ti₂AlNb diffusion welded joint increase. Based on the microstructure of the weld interface, welding deformation rate, and mechanical properties, the optimal Ti₂AlNb diffusion welding process parameters are 960 ℃, 5 MPa, and 120 min. Under this condition, the welding deformation rate is 5.4%. The Ti₂AlNb diffusion welded joint consists of B₂ phase matrix, some coarse lath-like α₂ phase, some equiaxed granular α₂ phase and some O phase distributed within the B₂ phase matrix. The tensile strength reaches 891 MPa at room temperature and 464 MPa at 700 ℃.

5B70 aluminum alloy plates with a thickness of 1.5 mm were welded using tungsten inert gas (TIG) welding with 5B71 filler wire. The mechanical properties and microstructures of the welded joints were investigated. The results show that under appropriate welding parameters, joints with excellent mechanical properties could be achieved. The tensile strength reached 342–350 MPa, the joint strength coefficient was 0.82–0.84, and the elongation at fracture was 9.5%–13%. The weld hardness ranged from 87HV to 93HV, with the minimum hardness located near the fusion line. The hardness profile exhibited a double V-shape. The fracture surface displayed a 45° shear morphology, characterized by a mixed mode of dimples and cleavage facets, with strengthening phase particles observed within some dimples. The fusion line of the joint was distinct, and the microstructures differed across the weld zone, fusion line, heat-affected zone, and base metal. The weld zone consisted of refined equiaxed grains with nonuniform sizes.

This paper takes a 4 mm-thick A7N01 aluminum alloy sheet as the research object and conducts simulations based on the laser-arc hybrid welding parameters of A7N01 aluminum alloy. Numerical simulations were performed using Fluent software to analyze the temperature field distribution and fluidity of the molten pool under different welding parameters, and to investigate how laser power and welding speed affect laser–arc hybrid welding. The results show that with the increase of laser power, the depth of the molten pool increases significantly. Meanwhile, the accelerated fluid flow speed inside the molten pool may enhance its instability. Although a higher welding speed can stabilize the molten pool in a shorter time, it is accompanied by a faster temperature change rate, which may lead to uneven cooling and the risk of cracking. On the contrary, a lower welding speed increases the heat input, resulting in a larger temperature gradient of the molten pool, which is conducive to forming a larger molten pool and deeper penetration. However, excessive heat input may also cause a series of welding defect problems.

In order to improve the poor friction and wear properties of soft metal, tungsten carbide (WC)-doped diamond-like carbon (DLC) coatings were prepared on the surface of different TC4-DT, TC21 and TB17 titanium alloys by medium frequency magnetron sputtering technology. The Ti/TiN/TiCN gradient transition layer was designed and fabricated by multi-arc ion plating. The influence of the matrix effect of different titanium alloys on the mechanical properties and frictional wear properties of WC– DLC coating was studied. The surface morphology and chemical element distribution of the coatings were analyzed by SEM and EDS, while the cross-sectional morphology and structure were observed by TEM, the structure of the coating was characterized by XRD and Raman spectra, and the mechanical properties such as bonding strength and Vickers hardness of the coating were tested by scratch tester and microhardness tester. Friction and wear prepared coating is more than two times higher than that of the three substrates, and the hardness of TC4-DT titanium alloy surface coating is the highest, reaching 1566HV0.05. The coating on TB17 titanium alloy has the strongest adhesion, whichis more than 53 N, and its friction and wear performance are also the best. The wear rate was 0.593×10^–6 mm³·N–1·m^–1, which is 99.79% lower than the substrate wear rate. However, the surface coating on TC21 titanium alloy shows the highest friction coefficient, the largest wear depth and wear rate among the three. The above results show that different substrate materials lead to differences in mechanical properties and bonding properties of diamond-like carbon coatings, which then affect the friction and wear properties of the coatings.

Shot peening improves the fatigue resistance of the workpiece by introducing residual compressive stress. As an important factor in shot peening process control, shot peening coverage significantly affects the residual stress and surface roughness of gears. However, the current research has paid little attention to the correlation between shot peening coverage and gear residual stress and surface roughness. Aiming at this problem, a simulation model for aircraft gear shot peening strengthening based on discrete element model (DEM) and finite element model (FEM) coupling was established. The influence of shot peening coverage on gear residual stress and surface roughness was studied through theoretical simulation and experimental verification. The results show that with the increase of coverage, the gear surface roughness S_a increases rapidly initially and then decreases gradually, when the coverage exceeds 200%, the surface roughness starts to decrease; The coverage has no significant effect on the residual compressive stress value and the depth of the residual compressive stress on the tooth surface, but has a greater effect on the maximum residual compressive stress. Maximum residual compressive stress increases significantly with the increase of the coverage, but the increase rate decreases when the coverage exceeds 300%; Along the tooth profile, the residual compressive stress exhibits the maximum value at the tooth root, and the position closer to the top of the tooth is smaller. This is because the collision probability between the projectile flow and the tooth surface increases as the position approaches the tooth root, and the higher number of impacts leads to greater compressive stress on the tooth surface.

This paper aims to explore the stress relaxation characteristics of TC11 titanium alloy. The finite elementmethod was adopted to simulate the laser shock peening and stress relaxation processes, and to analyze the influence of power density, number of impacts, and temperature on the stress relaxation of TC11 titanium alloy. The SIA–LSP–23 series laser shock peening system and the KSL–1700X–A2 high-temperature furnace were used to conduct laser shock peening and stress relaxation tests. When the temperature was 573 K, the power density was 5.09 GW/cm², and the number of impacts was 1 or 3, the error between the experimental data and the simulation results was less than 5%, indicating a good agreement between the simulated and  xperimental residual stress values. At a relaxation temperature of 573 K, an increase in power density had a greater effect on improving the stress relaxation limit than the number of impacts. However, the stress relaxation limit basically stopped changing after reaching 159.5 MPa, and it decreased as the temperature increased.