But we thought, anything that is good can still be made better. And we looked for a type of current generation that could provide welding current in the shortest possible time but that could be exactly controlled and dosed at the same time. Together with our research partner, the University of Magdeburg, we set to work. We developed and discarded ideas, pursued promising approaches to solutions and at the end were able to present a completely new process. During this we were supported by the Federal Ministry for Trade and Industry, which promoted our project in the frame of the Central Innovation Program for Medium-Sized Companies – ZIM. That is how short-pulse welding came into being. It combines the advantages of capacitor discharge welding with those of medium-frequency technology. And it opens new opportunities - for instance for spot and projection welding of aluminum or high-strength steels.
The transformers we use for short-pulse welding facilitate perfect high-current short welds. From 0 to 60 kA in less than 5 ms and a maximum power of 80 kA – those are values that lie far above those that can be achieved with conventional technologies. To be able to realize these peak values in reality, we developed a welding current inverter. Thanks to the high dynamics, with its aid the welding current can be adjusted lightning-fast. While reducing the welding time, we also managed to reduce the heat introduction into the vicinity of the welding zones by up to 30%. The size of the heat-affected zone was significantly reduced.
The transformers we work with during short-pulse welding are significantly smaller and lighter than those that are used during capacitor discharge methods. Not only does that have a positive effect on the circumference and weight of automated complete plants; the small transformer powerhouses can also be integrated into welding guns with no problem.
The increasing variety of materials used in lightweight construction and an increasingly wide pallet of construction variants with various sheet thicknesses and coatings have caused a significant increase in the requirements placed on weld-joining methods in past years. In a controlled regulated process, indissoluble connections have to be created for usage in the material mix. That is exactly what the short-pulse method facilitates, for instance during:
- Spot and projection welding of aluminum
- Welding nuts
- Connecting resistance welding elements and high-strength steels