Stud welding within sheet metal working tools

Sheet metal parts often have to be connected by fasteners. Within conventional process chains for the production of sheet metal parts, fasteners like bolts are mostly welded individually after the forming process and outside the working tool. This spatial separation of production steps requires complex handling operations and has negative impact upon the positioning accuracy of the fasteners. Every executable manufacturing step inside the sheet metal working tool shortens the process chain significantly. Furthermore, using a combined process the precision of position and orientation of fasteners improves. The challenges of integrating the welding process into the sheet metal working tool are some appropriate feeding technique, handling the emissions and associated pollutions of the tool as well as creating a dependable monitoring-system for the welding-process. Within the scope of a research project, a reliable technology for the integration of capacitor discharge (CD) stud welding with tip ignition was developed and tested. It complements existing solutions for integrated resistance welding processes. Due to its high-speed capability, low insertion of energy and only needed one-sided accessibility, this technique is particularly suitable for the integration in sheet metal working tools. A newly developed exhaustion-system is installed and tested for the first time by the CD arc stud welding process. The new technology produced top quality welding results along with high process stability and robustness in long-term tests.