Analysis of robotic welding possibilities of a car chassis assembly

Abstract

The continuous increase of the requirements regarding the quality of the welded joints (elimination of the influence of the human factor) but also the increase of the productivity of the technological processes imposed the analysis of the possibilities of implementing robotic welding processes. The introduction of robotic production lines is an increasingly common thing in the automotive industry. This paper presents the stages necessary for the realization in welded construction of a crossbeam, part of the chassis of a car. The elaborated welding technology aimed to achieve the transition from semi-mechanized welding of the assembly to robotic welding using the MAG (Metal Activ Gas) welding process. The basic material from which the crossbar is made is S355 MC steel, steel for constructions with high mechanical properties. For the robotic welding of the assembly, the design of the device necessary for the orientation and fixing of the components was made. The welding technology developed was validated by performing standard samples that were subjected to visual examination and penetrant testing but also to destructive examinations which consisted in measuring the hardness in the characteristic points of the welding bead and also by measuring its geometric characteristics. Following the analysis of the initial dimensional values obtained, it resulted that the incorrect positioning of the welding head in relation to the welded components led to the appearance of geometric defects of the welding seams, although the technological parameters of the welding regime were appropriate. After making adjustments on the position of the welding head, accepted characteristics were obtained which led to the decision to validate the welding technology used.