In the publication, the results of an experimental analysis of joint formation by pressing of DX51D steel sheets with thickness of 1.5 (mm) with the use of a rigid punch and an additional deformable rivet of various shapes were presented. The influence of the use of a steel rivet with a diameter d = 5 (mm), similar to the dimensions of the forming punch in the case of the classic clinching variety on the interlock parameters was investigated. The used die was with a four movable segments—dedicated to connections made in the clinch-riveting technology by TOX® PRESSOTECHNIK. In additional, experimental tests were made for joining sheets with a rivet of various shapes, i.e. with a through hole. Joints were formed and the correctness of the upper blockage in the lower sheet was observed on the joints cross-sections. The interlock parameters were measured for each joints samples. In order to compare the influence of using an additional rivet on interlock parameters and joints strength the traditional clinching joints were also made. The minimal thickness of the traditional clinching joint embossment for 2 sheets of 1.5 (mm) thickness for each was X = 0.75 (mm).

No abstract

In the case of thin-walled structures, the geometric accuracy of the products is particularly important. The implementation of the parts joining process requires various tools and technological equipment. For clinching joints, their geometric quality, energy requirement of the forming process, and joint load capacity are very important issues. Clinching technology has been used for at least two decades, and research is still being conducted to improve it. This paper presents the results of research on the impact of process modification, i.e., the use of different tools and the shape of the additional rivet, on the joint geometrical quality, the energy consumption of the forming process, distortion of the DX51D + Z/275 steel samples, and the load capacity of the joints. The research was carried out using three different sets of tools. The effect of changing the shape of the rivet (the hole and its diameter and depth) on the reduction of the forming force and the energy consumption of the joining process was analysed. For joints made with different tools and with an additional rivet, an analysis of the size of the sheet deviation was performed. Changes in the geometric structure of the joint interlock and changes in the surface flatness of the sheets in the area of the joint axis were observed. The impact of the proposed rivet modification on the change in the effectiveness of the forming process was determined. Identification of the strength of the joints was also carried out in the shear test of the lap joint. The energy consumption up to fracture was calculated. It has been found that it is possible to significantly increase the joint load capacity and reduce the forming force of the clinch-rivet joints.