Macro and micro fracture analysis shows that the ignition coil fixing bolt is mainly fractured by torsional load, and the micro fracture is a clockwise shear dimple. Through comparative analysis of simulated assembly test, the fracture surface of the failed part is consistent with the fracture surface of the bolt under pure torsional load, so the fracture mode of the bolt is torsional fracture failure (shear stress). The cause of torsional fracture may be that when the spark plug is replaced for the second time, the bolt is not screwed in normally (the internal thread is damaged or the bolt is screwed in obliquely), and the tightening torque is higher than the torsional fracture torque (14 N·m) of the bolt, which finally leads to the torsional fracture of the bolt.

The data of wireless Andon system in the prototyping workshop can indirectly reflect the actual running state of the workshop. In this paper, Qlik Sense was used to establish the analysis model for the data of the current and historical operation states of the Andon system. The current operation state analysis mainly facilitates users to quickly obtain the operation state of the project according to the dimensions of floor/project/workshop; the analysis of historical operation status focuses on the analysis of such dimensions as bottleneck station, single vehicle manufacturing cycle and vehicle delivery in the workshop. Finally, it realized the analysis of data standardization and visualization, helped engineers and managers quickly master workshop operation information, and became an effective tool to assist business improvement.

Considering the uneven distribution of Body in White(BIW) feature points, combined with the non-spatial attributes of feature points and based on the undigraph with weight, this paper proposed a parameter adaptive DBSCAN algorithm to improve the assembly quality of BIW which can identify the regional assembly deviation of continuous off-line BIW and realize the deviation area diagnosis and automatic alarm. Experiments show that this method can effectively monitor the error source, solve various faults in time and improve the quality of vehicle manufacturing.

For the problems of long data preparation time of project engineers in the wireless torque system, this paper first disassembles the data preparation work and clarifies that the issues to be solved are 3 points with long man-hour investment from the “project standards bill of materials” to “tool correctly invoke the tightening program” and standardize the data, and at the same time combine Python, VBA and other programming tools and methods to automate this part of the work. After the actual operation of several projects, the results show that the efficiency of data preprocessing has been improved by 76%, and the use of digital methods has promoted the trial production tightening system to play a further role in promoting intelligence.

This paper studied Radio Frequency Identification (RFID) technology, briefly summarized the basic definition, components and basic working principle of this technology, and elaborated in detail the application of SICK brand RFID in automatic welding production line, parameter setting method, hardware network composition principle, software control method and information analytic mode. The vehicle model information engraved in the tag is used to realize automatic identification and mixed flow production of high and low end models on the same production line, which has advantages of simple mounting type, fast identification, accurate information. The model production assignment is passed on from the principal computer to the line, which can remotely control model ratio, has high digitization production capability, and greatly improves production efficiency and automation level.