In order to promote the development of flat wire motor technologies for new energy vehicles and introduce it into large-scale production, this article studied the paint removal welding process in the manufacturing process chain. A paint removal process plan for flat wire motors was developed. Based on the requirements of product characteristics and combined with the evaluation method of paint removal effects, the article analyzed the correlation between residual organic matter, surface roughness, heat affected zone length, welding pulling force, residual organic matter on the paint removal surface, and clearly defined the RFU value of paint quality within a limited range. By comparing the paint removal effects of different flat wire paint film insulation schemes, the article concludes that the laser paint removal process is adaptable to various insulation schemes, reducing the costs of model change. The article also analyzed comprehensively, guided practice and application of this process plan in aspects of paint removal effects, investment, application and maintenance.

To ensure the calculation depth of the weld seam, reduce the heat input and improve the welding speed, a double-wire MUP welding method was developed for robot double-wire welding of the heavy truck axle. 4 welding control modes were developed, which were analyzed and compared in aspects of arc stability, heat input and waveform control. Mode 1 is front welding wire pulse welding plus rear wire Mixed Up Pulse (MUP) welding, Mode 2 is front wire MUP welding plus rear wire pure pulse welding, Mode 3 is MUP welding for both front and rear wires, front wire pulse corresponds to rear wire pulse and front wire DC corresponds to rear wire DC, mode 4 is MUP welding for both front and rear wires, front wire pulse corresponds to rear wire DC and front wire DC corresponds to rear wire pulse. When welding the axle longitudinal seam V-shaped groove, the use of Mode 1 can obtain consistent weld seam calculation depth, reduce the heat input, improve welding speed and obtain graceful weld seam appearance; Mode 2 is more suitable for rapid welding of thin plates, the use of Mode 3 can significantly reduce heat input to obtain graceful weld seam, improve arc stability and welding speed when welding axle reinforcement ring and rear axle housing, and Mode 4 is suitable for the welding of thick plate filling layer, which can stir the molten pool to promote rapid gas overflow and reduce the tendency of porosity in the weld.

In order to evaluate the weld seam fatigue life of suspension control arm accurately, this paper conducted weld seam fatigue analysis considering the interference fit stress. The interference fit stress of the control arm calculated by theoretical calculation and Finite Element Method (FEM) was compared, the fatigue load was equivalent treated, the fatigue conditions were simplified into three simple conditions. The “VOLVO” fatigue analysis method of weld seam was introduced, the fatigue life of control arm weld seam was checked by this method. The analysis results are in good agreement with the results of bench test, the optimized scheme successfully passes the vehicle durability verification.

This paper analyzed the problem of difficult installation of Printed Circuit Board Assembly (PCBA) caused by warping during trial production and identified wave soldering as the key factor through specific test comparison. ABAQUS was applied to perform thermal-structural coupling FEA simulation analysis of wave soldering process, it was concluded that poor temperature resistance of connector base material, large difference in thermal expansion coefficient between connector base material and PCBA material, uneven heating caused by process were the causes of PCBA warpage. Therefore, professional suggestions were provided and a series of verification schemes were developed for verification and improvement, which eventually eliminated PCBA warpage caused by wave soldering.

The fracture of a high-strength bolt used for fixing battery module of a new energy vehicle in the process of vibration test was investigated and analyzed through physical and chemical inspection, assembly process and vibration test. The results of investigation and analysis show that the cause of fracture is the formation of fatigue source caused by improper bolt assembly, the fatigue source continues to expand under the combined action of alternating stress and radial shear force at the upper and lower joint plane of the failed bolt along Z-direction vibration, which eventually leads to fracture.

Based on the experience of automobile development process, this paper proposed a set of technical solutions for improving the material utilization ratio of automobile parts, which involved the modeling design of parting line, product design, process design and die try out. According to the stamping synchronous engineering analysis and the die try out analysis as well as practical case, this paper compared the solution with the traditional technical solution, highlighting the advantages of the technical solution proposed in this paper. The results show that this solution can effectively reduce the material consumption, improve the material utilization ratio of parts and save the cost of vehicle manufacturing.

The First Time Through (FTT) of body outer cover panel is an important index of stamping quality evaluation. Taking the outer plate of aluminum cover as an example, this paper analyzed the problem of pitting and scratches and formulated countermeasures from 5 dimensions of man-machine material method ring. By improving the cleanliness of wire body, equipment and die, the surface state of die and the gap of longitudinal cutting tool of aluminum rolling were optimized, the tension control model of aluminum plate rolling process was adjusted, which reduced the frequency of pitting and scratch defects of aluminum cover outer plate, improved the FTT of aluminum outer cover from 85% to more than 92%.

In order to solve the problems of equipment shutdown and environmental pollution caused by the falling of the oxide scale of the hot-rolled strip used in the production of beam parts, this paper took the conversion and switching of EPS steel plate as the main research object, analyzed the causes for the falling of hot-rolled strip oxide scale during the rolling process by means of test verification and genchi genbutsu, analyzed the technical advantages of high surface quality of EPS steel plate and no need for shot blasting after the parts were formed. The paper proposed technical requirements of EPS materials: the yield strength of the steel plate is 530 MPa~560 MPa, the tensile strength is 600 MPa~630 MPa, the elongation after breaking is ≥22%, and the cold bending performance requirements need to be met. The average surface roughness Ra≤5.0 μm after EPS treatment. Finally, it led to the switch of EPS steel plate production.

To address the issue of automotive body weld seam sealant bubble, this paper started from the cause of automotive body sealant bubble, it firstly introduced 2 sealant bubble analysis methods including automotive body break-up analysis and section analysis, determined that excessive use of hemming sealant was the cause of sealant bubble, proposed the adjustment of slab gap and hemming sealant to eliminate sealant bubble. The results show that sealant bubble will be eliminated when slab gap is less than 0.02 mm, whereas adjustment of furnace temperature can only reduce the size of sealant bubble, can’t reduce the amount of sealant bubble.

This paper, by analyzing the failure mode of oil pump bushing during use and the press fitting process based on interference connection, determined the key quality control points of its assembly process, the contact stress p mainly depended on the interference amount δ and the elastic modulus of the 2 mating parts, the press-fitting quality can be directly evaluated by the press-in force F and the press-in depth l during the press-fitting process. By optimizing and improving the structure of oil pump bushing press-fitting equipment, increasing the press-fitting force and displacement monitoring, the press-fitting quality of the oil pump bushing can be effectively evaluated and continuously optimized to avoid the occurrence of after-sales quality incidents.

Due to the fact that riveting technology is mostly applied for aluminum connection, its application in automotive Body In White (BIW) is limited. To solve the issue of compatibility between riveting process and other basic processes, this paper studied the integration of multiple riveting processes, designed a scheme to achieve multiple riveting processes emplying a single robot, validation analysis was conducted. The integration mainly includes self-piercing riveting process, rivetless self-piercing riveting process and rotary tapping riveting process. Meanwhile this paper also objectively analyzed the post-integration of other processes. The validation results indicate that the integration of multiple riveting processes can improve equipment start-up rate, reduce production costs and energy consumption in a single production cycle.