To improve the internal quality and mechanical properties of magnesium alloy die-casting parts, this paper studies the influence of high and low speed switching position on the internal porosity and mechanical properties of AE44 magnesium alloy die-casting parts. The results show that compared with the traditional position of the punch when the alloy liquid reaches the inner gate as the high and low speed switching position, advancing the high and low speed switching position can reduce the porosity inside the casting and improve its mechanical properties. However, advancing the high and low speed switching position too much can actually increase the porosity and decrease the mechanical properties. That is mainly because advancing the high and low speed switching position can reduce the melt temperature drop of magnesium alloy during the filling process, which is beneficial for improving the fluidity of magnesium alloy and the discharge of residual air in the mold cavity. If the high and low speed switching position is advanced too much, it will increase the turbulence level when the melt fills the mold cavity, entrain more gas, and improve the porosity of the casting.

In recent years, thixomolding technology has imparted thriving vigor to the magnesium alloy industry. This paper reviews the development and application prospects of thixomolding technology for magnesium alloys. Firstly, the principle and distinctive advantages of thyroiodin process for magnesium alloys are described in detail. Subsequently, the historical development of magnesium thixomolding machines is summarized, highlighting that China is gradually be coming an innovation leader in the field of large-scale equipment teehnology. Furthermore, this paper analyzes the latest advancements in research on microstructure and properties of magnesium materials utilizing thixomolding technology, and points out that this technology can fully exploit the performance potential of magnesium alloy and effectively reduce casting defects. Beyond the commonly used Mg-Al system, novel semi-solid magnesium alloys are also being researched and developed. Concurrently, magnesium matrix composites by thixomolding have garnered attention due to short process and high performance. Thixomolding technology for magnesium alloys has been applied in consumer electronics, transportation tools, etc., and is gradually expanded to the production of large structural parts, especially demonstrating strong application potential in the field of new energy vehicles.

In order to improve the path planning efficiency of Automated Guided Vehicles (AGVs), the research is based on the Ant Colony Algorithm and Dijkstra’s Algorithm, taking the path length as the optimization objective, to conduct path planning for a single AGV. Firstly, the actual environment is simplified to MAKLINK environment by MAKLINK graph theory. Then, the shortest path of the starting point is obtained by Dijkstra algorithm. Finally, the path is optimized by ant colony algorithm to obtain the final selected path, which improves the transportation efficiency of AGV and reduces the energy consumption.

To improve the rationality of automotive spray design, spraying simulation technology is introduced to dynamically analyze the commissioning process of spraying robots on the basis of traditional spraying technology, and the paint film thickness effect is evaluated visually for the spraying path and spraying parameters. The results show that the matching rate between simulation calculation of painting film thickness and painting workshop reaches 84%, the homogeneity of painting film thickness is improved by 15%. In addition, the wastage of paint is reduced, paint cost is reduced by 5%, and varnish cost is reduced by 11%.

In order to address cracking failure of door arrester of a vehicle in door slamming durability test, polarized microscope and mold flow analysis are used to analyze defects in parts and develop process optimization measures. The results show that extending the shot blasting time of steel core can effectively remove surface burrs and reduce microdefect and stress concentration around sharp boundary after injection molding. Extending boiling time can improve water absorption of plastic cladding, thereby enhancing the notch impact strength and failure stress. Adding exhaust insert in the tooling can improve parting line and reduce air pockets inside the plastic cladding. Adjust injection hole of check link arm to transfer the uneven flow of material to low stress zone, reducing failure risk. Finally, the reliability of optimized parts is verified via door slamming durability test, which solves plastic cladding cracking failure.

Aiming at the concave deformation of a certain vehicle front door panel,this paper conducts a concavity resistance analysis and optimization on the front door outer panel through a joint numerical simulation. Firstly, Hypermesh is utilized to construct the CAE calculation files. Secondly, the uniform distribution method is applied to fix the loading points in the key areas of the front door panels. Thirdly, the successive loading method is utilized to load and unload the front door panels. Finally, the ABAQUS solver is called for calculation to obtain the “Force-Displacement” curve,the front door displacement contour plot, and residual deformation contour plot. The results show that the anti-denting performance of the key area of the original state of the front door outer panel is insufficient, requiring optimization and improvement. The optimization results indicate that the maximum displacement at point P₂ is reduced by 33.72 %, and the residual deformation is reduced by 86.66 %; the maximum displacement at point P₃ is reduced by 28.33 %, and the residual deformation is reduced by 96.58 %.

In order to optimize the off-line running, performance of line modification and transfer efficiency of Semi-knocked Down(SKD) vehicle bodies, this paper introduces the off-line, transshipment and assembly scheme of a domestic SKD vehicle for export. Taking a certain model as an example, the paper discusses the scheme and implementation method of how to use the fork transplanting machine and Radio Frequency Identification(RFID) identification with Manufacturing Execution System(MES) system to transfer the body of SKD export vehicle from domestic OEM production line to another Knocked Down(KD) workshop for assembly, and proposes corresponding solutions for the beat issue and empty skid reflux.

Resistance Spot Welding (RSW) is widely applied in automotive body manufacturing for its advantages such as high efficiency, high-quality, high automation and good flexibility. This paper commences by reviewing domestic and foreign research on RSW, including parameter optimization, electrode optimization, and new materials application, summarizes the current research status of RSW, it then delves into recent advancements in novel hybrid RSW technologies, such as ultrasonic hybrid resistance welding and laser hybrid resistance welding. Lastly, based on the current research status, the paper identifies existing issues and proposes future directions for development.

In order to improve safety performance of new energy vehicles (NEVs), this paper studies safety regulation insulation testing in NEV factories, especially the application of synchronous mobile technology therein. By analyzing the situation and existing problems of the current detection process, the paper proposes solutions based on synchronous mobile technology. From the theoretical basis of synchronous mobile technology to specific applications, this paper elaborates on multiple dimensions such as process planning, equipment design, and safety guarantee. Practice has proved that this solution has achieved an online follow-up detection mode with high cycle rate, high flexibility and high safety, it thereby is an efficient, accurate and reliable insulation detection solution, ensuring the safety and compliance of new energy vehicles.

In order to achieve the connectors docking of automatic charging robots for elevtric vehicles under Low-precision conditions, a connector flexible docking mechanism with 4 degrees of freedom has been designed. Through tolerance analysis, the flexible mechanism can satisfy the requirement of operation range when the positioning deviation is 10 mm and angle deviation is 5°. Force analysis determines the adjustement of design parameters to reduce insertion and extraction force. Simulation analysis and actual experiment prove that the insertion and extraction force is under 140 N which satisfies the requirement specified by standard.