Consideration of the manufacturing history of sheet metal components for the adaptation of a clinching process

Abstract

The process chain for the manufacturing of sheet metal components in mass production includes various cutting and forming operations, which influence the resulting properties of the parts and therefore subsequent manufacturing steps, such as clamping and joining. It is shown that clamping of the components leads to superimposed residual stresses and geometry changes. Therefore, the part properties differ from the initial state of the semifinished products, which has to be considered in the design of clinched joints. This paper presents an approach for coupled determination of the properties of semifinished and finished parts during deep drawing and clamping as well as their effects on the joint quality during clinching. One method for the effective and efficient determination of the properties of semifinished products and components during production is using process data from the preceding manufacturing processes, which is concretely presented in this work. In addition to the interconnection of the entire production chain, it is necessary to define relevant process data for each individual manufacturing step and to correlate the data with the material properties reliably. Therefore, the cross-process interactions of different steps of the process chain for the manufacturing of sheet metal components and the effect of process variations on subsequent manufacturing steps are investigated. Consequently, the boundary conditions for a mechanical joining process based on data from preceding process steps can be predicted.

Mechanical joining of high-strength multi-material systems − trends and innovations

“…The named publications aim to adapt the forming processes in order to maintain the part quality. In [98], an approach is shown, which aims to provide knowledge on the part properties as result of forming, cutting and clamping operations in order to adapt a subsequent joining process. Since the joining operation follows forming operations, it offers the opportunity to compensate for deviations along the process chain to a certain extent.…”

“…Since the joining operation follows forming operations, it offers the opportunity to compensate for deviations along the process chain to a certain extent. In [98], a demonstrator geometry is deep drawn with different blank holder forces in order to set different part properties in the joining zone. After laser cutting the remaining flange, the part is clamped with another sheet metal component using a smart clamping device, which is equipped with force and angle sensors.…”

“…18). Thus, the tool setup and parameters, which were determined with a standard sampling process, lead to a good joint quality without the occurrence of cracks [98]. By increasing the blank holder force to 800 kN, the conditions differ distinctly from the initial state.…”

“…Next to the displayed properties, the blank holder force during drawing also influences the springback behavior and the dimensional accuracy of the drawn part [98]. The increase of the blank holder force from 130 kN to 800 kN results in the reduction of springback and in the improved dimensional accuracy of the demonstrator geometry.…”

Performance Tests of HX340 Microalloyed Steel Sheets Joined Using Clinch-Rivet Technology

“…When joining using the clinch-riveting method, the continuity of the material of the joined sheets is maintained, and there is no intentional puncture of the joined material layers. As a result of the use of an additional rivet to form the clinch joint, a relatively large increase in the maximum load capacity is achieved [16][17][18]. Another way to strengthen the clinch joint is to use additional adhesive in the process of assembling the sheet-metal elements [19].…”