In order to achieve the goals of improving product performance index, technological innovation, reducing cost, shortening manufacturing cycle and personalized customization, this article made in-depth technical research on the metal 3D printing Selective Laser Melting (SLM) process to make aluminum alloy (AlSi10Mg) and stainless steel (316L) material parts. The article mainly studied the optimization of metal 3D printing support process, exploration of unsupported technology, mechanical properties of parts and its application in automotive products, and explored its practical application scenarios. According to the exploration results, the article summarized the process guidance specification of metal 3D printing supporting technology and the exploration rules of unsupported technology, and the specific values of mechanical properties of printed parts. Meanwhile, the application scenarios of automobile parts were developed, and the traditional parts with complex, long cycle and high cost were replaced by metal 3D printing laser selective melting (SLM) process. It provides theoretical basis and practical case reference for further application of metal 3D printing technology in automobile parts.

2 test methods, i.e. neutral salt spray method and cyclic corrosion method are utilized to study the effects of different test environments on the corrosion morphology, typical corrosion depth, corrosion products and mechanical properties of A380, YL113 and YL104 alloys. The composition of corrosion products and its corrosion mechanism are explored. The results show that, after 504 h neutral salt spray and 60 days cyclic corrosion test, the corrosion resistance of A380 alloy is the worst among the 3 die-casting aluminum alloys. Under the 2 test environments, the tensile strength of A380 alloy is reduced by 31% and 38% respectively; followed by YL113 alloy, its tensile strength decreases by 13% and 25% respectively; the tensile strength of YL104 alloy decreases by 3.6% and 1% respectively. The root cause of corrosion of these die casting alloys is that, the potential difference between phases in the matrix and the humid environment on the sample surface constitute electrochemical corrosion, which leads to corrosion.

Automotive cooling hose with polyamid(PA66) as the host material was developed to replace the long chain nylon materials (including PA12, PA612, PA11 and so on), which solved many disadvantages of long chain nylon materials such as costliness, resource shortage and complex production processes. This article firstly introduced the development of hydrolysis resistant and flexible PA66 material. Adding toughening agent and hydrolytic resistant agent to PA66 material through blending modification effectively improved toughness and hydrolytic resistance, and the material performance index conformed to usage requirement. Then conventional hose extrusion process was applied to PA66 modified material for hose extrusion trial production. The test shows that burst strength of PA66 hose is greater than 2.6 MPa, which is still greater than 1.8 MPa after long-term use of coolant resistant fluid, proving it comply with the basic use condition of vehicle.

Based on the actual project experience and the study of the actual cases, this article emphatically analyzed the requirements of the positioning system for the integrated automatic assembly system, sorted out the coordination relationship and structural characteristics between the 4 positioning systems of body floor Reference Point System（RPS） positioning system, body & sling positioning system, sling & assembly station positioning system and pallet & body positioning system, it also introduced the main process and physical elements of assembly planning, including but not limited to key planning elements such as floor layout, conveyor system, assembly system and tightening system, so as to provide reference for the planning and design of assembly process.

This paper summed up the causes of chip and solutions through many practical cases of mold chip maintenance experience. The paper analyzed in detail the process from sheet metal to stamping parts, described the blanking, press equipment and die, in particular it analyzed the die from drawing chip, trimming and punching chip and flanging chip. Such analysis was reflected to matters for attention regarding material chip in the new project mold acceptance, and a set of chip maintenance standard process was formed, which can be directly used for reference when the chip appears.

By studying the principle of resistance spot welding and the actual state of field production, combined with the BOSCH controller, curve analysis of UIR and the splash statistics function, this article analyzed the causes of splash in resistance spot welding. According to the cause of splash, hardware adjustment, parameter adjustment and Bosch software function were adopted to reduce splash rate. The results show that the above experiment effectively reduces splash rate, guarantees welding quality, extends the service life of fixtures, grips and welding clamps and other equipment, and improves the field operation environment of welding.

At present, the disposal of waste solvent for water-borne paint cleaning is a problem of the automotive industry that is difficult to overcome for high disposal cost and high technological difficulty. In order to solve this problem, membrane separation material & recycling technology was invented, which separated and recycled the waste solvent produced in painting and color change and cleaning of painting equipment by membrane separation & recycling technology. In this process, 75% of water was recycled and reused in the painting line, while the paint was extracted to make renewable paint, the material was thus recycled and reused. The technology has been applied to Audi painting line for 2 years with reliable performance, the cost reduction of the 150,000 units painting line exceeded 5 million yuan.

The factors affecting stamping parts in the production process are complex, and the correct use of grid test can effectively guide the optimization of necking and tearing of stamping parts qualitatively and quantitatively, can make stamping parts have a greater “Safety margin” in the stamping process, thus speeding up the speed of problem solving. Through Forming Limit Curve(FLC) analysis and Comsmart equipment measurement, the production guidance data can quantify and reflect the actual status of the mould, and then make specific mould margin adjustment and verify the adjusted mould margin.

For the differences between BIW aluminum parts joining technology routes in Germany and Japan, the article adopted the research method of typical and benchmarking analysis to describe the principle, forming process and process characteristics of aluminum parts joining technologies of VW AG and Toyota Company, and compared the process technology routes of VW and Toyota from 4 aspects of lightweight, quality, efficiency and cost, and formed a comparative analysis table for the types of BIW aluminum parts and joining processes of VW and Toyota. It is concluded in this article that the types of BIW aluminum parts, joining processes and investment of VW are more than those of Toyota’s, which all meet their quality requirements. The article proposed that FAW should draw on the application experience of aluminum joining technologies of VW and Toyota.

The self piercing riveting & bonding composite connection point with aluminum plate was taken as the research object. In the early stage, through the dynamic tensile test and CAE simulation modeling calibration of the connection point under 3 working conditions of tension shear, tear and forward tension, the parameters in the constitutive relationship of CAE simulation model were accurately obtained. Finally, the comparative verification test of CAE collision simulation and high-speed impact was carried out for T-shaped components with multiple working conditions, CAE simulation accurately predicted and realized the failure of the connection point, and the simulation accuracy reached 95.9%. It accurately characterized the deformation and failure behavior of the riveted-bonded composite connection point under mixed complex working conditions, which has high practicability in the CAE simulation of vehicle collision.

In order to improve the efficiency of the electric drive system for electric vehicles, this article summarized the solutions to improve the efficiency of the electric drive system in motor design, material selection, process assembly and other aspects. In the motor design, motor suitable for the electric vehicle was selected, and the control algorithm was optimized; in terms of materials, copper wires, silicon steel materials and high-frequency materials with high performance were selected; in process assembly, the application of flat wire winding process can improve the torque and efficiency of the motor, the core and stacking process were optimized to reduce the motor iron loss. The efficiency of motor drive system for electric vehicles can be improved by increasing the system output efficiency and reducing various losses.