34 n ROBOTICS AND AUTOMATED MANUFACTURING July/August 2025 www.drivesncontrols.com Digital twins help stove-maker to meet its burning ambitions The family-owned German company Hase Kaminofenbau has been manufacturing woodburning stoves since 1979. It now produces up to 15,000 stoves a year and employs around 200 people. The increasing demand for clean, modern stoves presented Hase with several challenges. “A stove has many weld seams – welding them all manually takes a very long time,” explains the company’s head of production development, Florian Fischer. “Due to the fact that we were faced with an increasing shortage of welding specialists, and that our production facilities were getting older, we were only able to benefit from the booming market by automating our production.” Welding stoves is challenging due, in part, to the high temperatures involved. Having this work done by robots would free up human workers for other tasks, such as welding the combustion chamber doors, where the working area is too small for a welding robot. Hase’s aims were clear: to increase productivity, ensure quality and at the same time reduce the workload on its employees. “We wanted to build an ultra-modern, flexible robotic system that would also be able to process future models that don’t even exist yet, without placing constraints on our designers or bringing production to a standstill,” explains Fischer. “That’s why the digital twin plays a crucial role.” The use of digital twin simulation software has been a game-changer for Hase. The software it is using – Kuka’s Kuka.Sim – brings robot applications to life virtually, before the system starts to operate. Robot motion sequences are programmed offline and can be depicted in real time. They are then analysed and their cycle times are optimised. Hase is using an add-on called Kuka.Sim ArcWelding that simulates the automatic welding applications. It can, for example, define approach positions and the optimum orientation of the robot for the welding process. The add-on allows Hase to simulate all welding sequences and motion sequences in advance. “We can create a stove program offline in two hours with the help of the digital twin,” says the company’s programmer, Martin Altmeier. “To do this online, we would have to take a system out of operation for two weeks. Our production and the development of new models would not be possible as quickly and easily without the offline programming via the simulation software.” Comparing ideas Hase is also using the digital twin software to compare ideas for new stove models early in the prototype phase. The company’s designers receive an image of the production process, allowing them to test welding sequences for new stoves, which are then used to create the weld programs for the robotic cell. Once the program for a new stove is ready, the robots can get to work. A positioner lifts the pre-tacked stove, weighing 20–100kg, and moves it to the desired location. A German manufacturer of wood-burning stoves has turned to digital twins and welding robots to help it meet a growing demand for its products at a time when welding skills are increasingly difficult to find. Hase is using a pair of Kuka welding robots running on a linear axis to weld the seams of its oven components
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