Fundamental analysis of the in situ simulation of resistance spot welding processes

电阻点焊是一种操作简单、生产效率高、工作可靠的金属材料连接工艺。由于其高经济性和可实现的低周期时间，电阻点焊越来越多地用于要求苛刻的焊接接头，例如轻金属板的连接，薄板厚板连接，混合化合物和涂覆板。随着公差范围的收紧以及质量要求的稳步增长，对过程进行安全控制的必要性就出现了。甚至要求对每个单独的焊接点进行质量评估也是可能的。破坏性测试程序不能用于100%的检验。无损检测方法（NDT）是目前正在发展和使用的第一个实际应用。但是，无损检测总是需要额外的设备和组织努力。除了无损检测之外，由于整个工艺链（例如，从线圈上的金属片到成品车身）的生产数字化，可以获得大量特定对象的数据和参数。这些数据可以在未来用于每个工艺步骤中每个单独工件的基于仿真的分析。这种新方法可以显著减少破坏性或非破坏性测试的工作量。为此，利用对当前工件有效的工艺数据和参数，对电阻焊过程进行了现场仿真（在焊接逆变器中实现的与工艺相关的实时仿真）。关键焊缝可以自动识别并选择进行进一步测试。此外，现场模拟允许机器操作员直观地“洞察”焊接连接，通过可视化刚刚创建的焊接熔核。此外，预模拟可以在“现场”进行，即在机器上进行，例如确定焊接范围图或参数调整。本研究项目的目的是开发、实施和测试适合电阻点焊过程现场模拟的模型方法。最后，对原位模拟的潜力进行了实验研究和评价。

Resistance spot welding is a joining process for metallic materials which is simple to implement, highly productive and reliable. Due to its high economy and the achievable low cycle times, resistance spot welding is increasingly used for demanding welded joints, such as the joining of light metal sheets, thin-plate thick-plate connections, mixed compounds and coated sheets. With tighter tolerance zones in combination with a steady increase in quality requirements the necessity of a secure control of the process occurs. Even the requirement of a quality assessment of each individual welding point is possible. Destructive testing procedures cannot be used for this 100% inspection. Nondestructive testing methods (NDT) are currently being developed and used in the first practical applications. But, NDT always involves additional equipment and organizational effort. In addition to NDT, a large number of object-specific data and parameters are available due to the digitization of production over the entire process chain (e.g. from the sheet metal on the coil to the finished car-body). These data can be used in the future for the simulation-based analysis of each individual workpiece in each process step. This new approach can significantly reduce the effort for destructive or non-destructive testing. For this purpose, an in-situ simulation (a process-related, real-time-capable simulation, implemented in the welding inverter), of the resistance welding process is carried out with the process data and parameters valid for the current workpiece. Critical welds can be identified automatically and selected for further testing. Furthermore, the in-situ simulation with allows the machine operator an intuitive "insight" into the welded connection by visualizing the weld nugget that has just been created. In addition, pre-simulations can be carried out "in-situ", i.e. on the machine, for example for the determination of welding range diagrams or parameter adjustments.The aim of this research project is to develop, implement and test suitable model approaches for the in-situ simulation of resistance spot welding processes. Finally, the potential of in-situ simulation will be investigated and evaluated experimentally.