Bolt connection is the most commonly used connection technology in automobile industry, its connection failure is a common problem in automobiles, in particular, bolt looseness is the most common problem. Through the research on self-tapping locking bolt, it is found that it has the advantages of high connection reliability, repeated use and low system cost. Through the bolt assembly process development, the difference of torque-clamping force relationship with ordinary bolts was distinguished, the assembly process parameters were determined and reliable bolt connection was realized.

Based on the technologies of vision detection, Automated Guided Vehicle (AGV) transmission, industrial robot intelligent grasping and automatic tightening, the automatic assembly efficiency, assembly quality and flexibility of welding and adjusting door cover have been greatly improved. The multi-channel cameras were integrated on the grab, and the key feature points were identified and extracted by taking photos of the door cover and the body-in-white, and the clearance and difference of each position between the door cover and the body-in-white were calculated, and then the clearance and difference matching algorithm was adopted to calculate the best position of the door cover relative to the body in white, then the transfer robot was guided to grab the door cover to reach the best assembly position. The door cover was tightened automatically by the tightening robot carrying the tightening shaft. The door cover automatic assembly technology not only improves the assembly efficiency and quality, but also reduces the labor load and cost, and ensures the overall appearance quality of the body-in-white.

This paper introduced the planning layout, equipment composition, process flow and application prospect of the workstation through survey and research on the CMT arc welding workstation of the new dual-machine coordinated robot with positioner. In combination with the application description of the emerging technology of arc welding quality tracing system and arc welding visual guidance system in arc welding process, this paper expounded how to solve the problems of low robot utilization rate, low welding efficiency and poor control of weld quality of traditional arc welding workstation. The purpose of improving and optimizing of arc welding process, in-depth research and development has been realized, and the efficiency and intelligence of arc welding workstation have been improved.

Using the traditional personnel beat calculation method usually can only calculate the approximate time, which is quite different from the actual result. This paper elaborated the principle of Methods-Time Measurement (MTM) calculation method, through the MTM analysis, accurate calculation of worders load of the welding line, at the same time introduced different kinds of feeding ports of the automobile welding line and analyzed its advantages and disadvantages. According to the calculation results of MTM, this paper proposed the optimization scheme of the worker number on the welding line and the form of feeding port to ensure the rationality of the workers number and improve the efficiency of the factory.

The process design stage for stampings of the Body In White (BIW) is an important stage to improve material utilization rate. This paper elaborated in details methods to improve material utilization rate in the process design stage from 5 aspects, i.e. forming method, process supplement, sheet shape, waste utilization, and thinning rate inspection. There are relatively few studies especially in process supplement. The material utilization rate of stamping parts can be improved by optimizing the distance between the workpiece boundary line and the root of the punch fillet, the width of the drawing management surface, and the drawing parting line, this provides new ideas and approaches for improving material utilization rate.

This paper elaborated the application trend of mechanical connection technology in automotive Body In White (BIW) manufacturing. Semi-hollow and self-piercing riveting technology as the most widely applied technology of steel aluminum connecting, its process technology parameters are crucial to BIW connection strength. This paper elaborated the semi-hollow and self-piercing riveting process and quality control method as well as 2 common quality defects of semi-hollow self-piercing rivet of BIW in mass production of automobile, analyzed the influencing factors of lack of height and rupture of closed end of rivet. By commissioning of riveting equipment and optimization of riveting process parameters, the above defects were solved, providing solution and direction to solve quality issues in BIW manufacturing.

With aluminum alloy piston of automobile engine as the research object, a thermal insulation performance analysis simulation model of plasma spraying coating was established, the influences of bonding layer material and porosity on thermal insulation performance of coating were analyzed comprehensively, and the thermal insulation performance of coating sample block was verified by test. The test results show that, the thermal insulation coating can significantly reduce the temperature of piston metal matrix, and the thermal insulation performance of ZrO2 thermal insulation layer +NiCrAlY bonding layer is the best. With the increase of porosity of bonding layer, the thermal insulation performance of coating improves, but the mechanical bonding strength between coating and matrix decreases due to excessive porosity, considering the results of thermal insulation and bonding strength, the best material for bonding layer is NiCrAlY, and the best porosity is 10%. After spraying the thermal insulation coating, the equivalent thermal stress value of the piston meets the design requirements of the product under actual working conditions.

In this paper, based on the poor dimension matching accuracy of engine hood caused by the deformation of gas springs acting on the hood, through the simulation analysis of CATIA three-dimensional virtual assembly, and using MATLAB to numerically optimize the installation parameters of gas springs, reasonable design parameters of gas spring were worked out, and then corresponding design changes were made, and the assembly effect on the real vehicle was verified, controlling the dimension matching accuracy of engine hood within the target range. For the design parameters’ change law of the engine hood gas springs, the following conclusions can be drawn: (1) the more front gas springs are installed on the engine hood, and the more backward gas springs are installed on the vehicle body, the larger the elastic force ratio of gas springs is; (2) the more front gas springs are installed on the engine hood, and the more front gas springs are installed on the vehicle body, the larger its travel S is; (3) in order to improve the deformation problem of the gas springs acting on engine hood, the gas springs should be installed as front as possible on the engine hood, on account of reducing the maximum compressive force.

The welding line of automotive side wall inner panel was simulated, the PDPS software was used to model the welding line of the automotive side wall inner panel and simulate the production processes, i.e. workpiece loading, fixture open & close, robot welding, workpiece blanking. The simulation research results are as follows, by adjusting the welding gun path or the welding gun attitude, the solder joint accessibility is achieved and collision interference is avoided, adjust the welding process of the welding robot according to the change of the joint value and rotation angle of the 6-DOF manipulator, and control the production time of the production line through the simulation of the production beat of the station operation.

To meet the product development requirements of a domestic motorcycle enterprise, the bending impact, contact fatigue and single-tooth bending fatigue of 3 kinds of automobile gear steels were tested and compared. The advantages and disadvantages of service performance of those 3 kinds of gear steel were comprehensively evaluated by means of metallography, hardness and fracture surface. On this basis, the application effectiveness of the 3 kinds of gear steels was further verified from the perspective of parts. The results show that the comprehensive mechanical properties, process properties, contact fatigue and bending fatigue of 16MnCr5H are equivalent to those of 20CrMoH, and better than 20CrMnTiH. Therefore, 16MnCr5H can replace 20CrMoH and 20CrMnTiH to manufacture high-load motorcycle gears and meet the performance improvement and application cost performance targets.