To deal with the limitation of the existing non-destructive testing technology for the depth of the carburized layer of axle steel, a weak magnetic detection method is proposed. Since the stress concentrates at the junction of the carburized layer and its heart and can’t be eliminated, and then externally show a specific magnetic induction intensity for non. By collecting magnetic field signals from different samples of axle steel and different parts of axle steel, we analyzed the corresponding relationship between magnetic induction intensity amplitude and depth, and constructed a mathematical model for weak magnetic detection. The test results show that: spline outer circle (standard thickness/inspection thickness/absolute error): 3.50 mm/3.57 mm/0.07 mm; rod outer circle: 4.30 mm/4.46 mm/0.16 mm; R-angle: 4.00 mm/3.86 mm/-0.14 mm. The overall relative error of the inspection accuracy is less than 5%, which meets the actual needs of the factory inspection.

Since the line has to be stopped when replacing the electrode tip, the Overall Equipment Effectiveness (OEE) improvement of the automatic production line and manufacturing cost of per vehicle will be affected directly. To address this issue, this paper analyzed the electrode tip replacement time and frequency, used the linear programming model method to build a data replacement analysis model, summarized the risk level of replacement in different scenarios according to practical experience. At the same time, the standardized method of “fixed person, fixed time, fixed station” was implemented, and the final solution was determined after repeated iterative adjustment. After the grouping electrode tip replacement according to this strategy, the replacement frequency and time of electrode tip in the production line area has been reduced, and the overall OEE index has been significantly improved. At the same time, the cost of unit vehicle auxiliary materials was also optimized.

In order to solve the problem that the cross-sectional parameters of AutoForm drawbead could not be directly used in 3D software design, this paper derived solution formula for the cross-sectional parameters of Z-direction drawbead that could be directly used in 3D software, mainly including the distance between the Z-direction elevation on the inflow and outflow sides and the centerline of the drawbead, convex fillets, and concave fillets. The drawbead designed using CATIA software was compared with the drawbead automatically generated by AutoForm, which yielded ideal validation results, with both the width and height errors controlled within the range of 0.05mm, and the draw-in error was controlled in 1 millimeter.

To reduce the adverse effect of aluminum silicon coating layer on the surface of steel plate on laser joint, laser wire filler welding joint with aluminum mass fraction less than 1% in weld was obtained by using thin-coated hot-formed steel material and laser wire filler welding technology. The macro and microstructure of the welded joint were analyzed, it was found that the welded joint was replaced by the whole martensite structure after hot forming, which avoided the softening phenomenon. The mechanical property analysis shows that the tensile strength of the sample increases from about 570 MPa to about 1 500 MPa after hot forming, and the weak link of the joint is located in the base material. High speed tensile has no adverse effect on the tensile strength of the joint, but the elongation at break is affected greatly.

Static mechanical properties of blind end riveting connection between steel panel and three-dimensional braided carbon fiber panel was studied. The static test of blind end riveting connection combination with two different material thicknesses with the same specimen width and end distance was carried out. Then, the static test was carried out on the blind-end riveting connection combination with the same material thickness with different specimen width and end distance, so as to study the influence of mechanical property, failure mode, specimen width and end distance on its static performance. The research shows that good mechanical properties can be obtained by using blind end rivet to connect steel panel and carbon fiber panel. The failure mode and the maximum failure load of the connection are related to the cutting direction of the three-dimensional braided carbon fiber panel. The specimen width and the end distance have an effect on the failure mode and the maximum failure load of the connection.

For the forward design of extruded aluminum door sill section in side pole crash condition, this paper analyzed the pros and cons of the Equivalent Static Load (ESL) based nonlinear optimization and traditional optimization technology. The research indicate that the ESL based nonlinear topology optimization design can obtain a topology path closer to the strategic requirement of crash safety structural deformation in the concept design phase than the traditional linear topology optimization, whereas in the detailed design stage, the ESL based thickness optimization method is better than the traditional approximate model value optimization technology in optimization efficiency and optimization scheme performance.

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 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.

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.

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.