Industry 4.0 Automation in Stove Production: Digital Twin for the Welding Robot

Automated welding of unfinished stoves while accommodating a broad product portfolio – this is the objective of HASE Kaminofenbau GmbH, based in Trier, Germany. The innovative stove manufacturer, located in the southwest of the country, introduces one or two new models to the market each year. Thanks to the seamless interaction between digital twin technology and KUKA welding robots, HASE is now well-equipped to meet growing demand with ease.

Automation ensures comfort: modern stoves are all the rage

Cozy warmth, crackling wood, glowing fire: for more and more people, a wood-burning stove is the epitome of cozy snugness and a must-have for the living room. This is why demand is constantly increasing at the Trier-based stove manufacturer HASE. Founded in 1979, the family-owned company now produces up to 15,000 stoves a year – and thanks to automation, more quickly and efficiently than ever before. The particular highlight: HASE manufactures 100 percent of its stoves at its location in the Rhineland-Palatinate region, with a workforce of around 200 employees. In addition to quality “Made in Germany”, the stove specialist relies on innovative technical solutions – with new stove models each year, intelligent iQ software for a clean fire and the robotic automation of production for greater process efficiency. The interface between physical machines and digital applications plays a decisive role here.

Due to the increasing shortage of welding specialists, we have only been able to benefit from the booming market by automating our production.

Florian Fischer, Head of Production Development at HASE

Meeting high demand with automated production

The increasing demand for clean, modern stoves presented the regional manufacturing company with a number of challenges. “A stove has many weld seams – welding them all manually takes a very long time,” says Florian Fischer, Head of Production Development at HASE. “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.” The welding work on the unfinished stoves is challenging, due in part to the high temperatures involved; having this work carried out by robots frees up their human colleagues to concentrate on other tasks. These include, for example, welding combustion chamber doors, where the working area is too confined for a welding robot.

Digital twin at the heart of the welding system

The manufacturer’s goal was clear: to increase productivity, ensure quality and at the same time reduce the workload of employees by means of welding robots. HASE would not be HASE, however, if the innovative fireplace manufacturer did not think ahead. “We wanted to build an ultra-modern, flexible robotic system that will 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 also plays a crucial role.”

At HASE Kaminofenbau in Trier, traditional craftsmanship meets innovative automation.

Since HASE has already been relying on the performance of robots from KUKA for 20 years, and the leading supplier of intelligent robotic technology was also chosen for the latest project. The particularly attractive feature of the collaboration was not only the possibility of using KUKA hardware in the form of two KR CYBERTECH nano ARC HW robots, the KUKA KL250-3 linear unit and the positioner. The game changer for HASE was the interaction with the KUKA.Sim software and the digital twin. The simulation software brings robot applications virtually to life – before the system has even been put into operation. The robot motion sequences programmed offline are depicted in real time then analyzed and optimized with regard to their cycle times. Furthermore, the KUKA.Sim ArcWelding add-on simulates the automatic welding applications. This means that approach positions or the optimum orientation of the robot for the welding process can be defined, for example.

Faster offline programming of stove models

“We simulate all welding sequences and motion sequences of our two robots on the linear unit in advance with the help of KUKA.Sim, completely encapsulated from the actual system,” says HASE programmer Martin Altmeier. "We can program a stove program offline in two hours with the help of the digital twin. 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 so quickly and easily without the offline programming via the simulation software.”

The two KR CYBERTECH nano ARC welding robots on the linear track weld the seams of the components.

KUKA.Sim can also be used to compare the designers’ ideas for new stove models with reality at a very early stage in the prototype phase. With the help of the digital twin, HASE can simulate the welding processes one-to-one and the designers receive an identical image of the subsequent production process. This enables HASE to use the digital twin to test welding sequences for new stoves, which ultimately serves as the basis for creating the corresponding weld program for the robotic cell.

Automation meets flexibility

Once the program for a stove model is ready, the robots can get straight to work. The machine operator places the stove in the system using a lifting device and starts the program. The positioner lifts the pre-tacked stove, weighing between 20 and 100 kilograms depending on the model, and moves it into the desired position. The two KR CYBERTECH nano ARC welding robots on the linear track – connected to two Fronius TPS 500i power sources – then automatically weld the seams of the components in the specified sequence. “Beforehand, we used the simulation to determine exactly when which robot would best take over which weld seam,” explains programmer Altmeier, “in order to prevent distortion, ensure that the seams are tight and achieve the optimum cycle time.”

Thanks to the digital twin, the designers already receive an identical image of the production process during the prototype phase.

The risk of failure is minimized

With various user levels and clear role profiles, such as that of the operator, HASE has significantly reduced the risk of failure due to operating errors. In addition, all current programs are backed up in the KUKA software – so even if an error occurs, all data can be restored immediately. “We wanted to connect the virtual world optimally with the real world,” says Bernd von der Bank from long-standing KUKA system partner Paul von der Bank GmbH, describing his intention for the project. “It doesn’t matter whether I change something on the system or in the simulation, as the same thing happens in both. The fact that the online and real worlds harmonize so well is unique in the market.”

The stove professionals from HASE, KUKA’s automation experts and system partner Paul von der Bank GmbH worked hand in hand.

KUKA applications offer consistent virtual and real control

Before KUKA.Sim and the welding robots could work together seamlessly, HASE, system integrator Paul from Bank GmbH and KUKA Customer Service collaborated to further develop the software and create a custom solution. In particular, HASE's expertise played a crucial role in achieving the successful final result. of HASE was of decisive importance for the successful final result. “The challenge with electric welding is that the virtual world has no tolerances,” says von der Bank. “The actual joining technology, on the other hand, does – and they are not exactly small.”

The customized automation solution for HASE enables the production of a wide variety of stove models.

Modular software architecture enables customer-specific requirements

To ensure that the simulation of welding seams and the welding parameters optimally matched the work of the robot controller and that the “post-teaching effort” was as low as possible, all parties worked together to modify KUKA.Sim according to HASE’s needs – the modular product architecture of the software makes this possible! One important advantage here: the data is 100 percent consistent, meaning the virtual controller and the real controller work with the exact same data. This way, KUKA.Sim creates the basis for virtual start-up.

Thanks to its modular product architecture, the software is precisely tailored to HASE’s requirements.

Advanced robotic system provides increased productivity

Thanks to the seamless interaction between the digital twin and the robots, HASE was able to reduce the welding time per stove from 45 minutes to 15 minutes. Following a positive experience with the system, HASE built a second, identical unit. This keeps the workload for programming and control low. The two new systems have replaced five older ones, resulting in significant space savings on the production floor.

Precise and efficient: Thanks to the excellent interaction between the digital twin and the robots, the welding time per stove was reduced from 45 minutes to 15.

We can program a stove program offline in two hours with the aid of the digital twin – to do this online, we would have to take a system out of operation for two weeks.

Martin Altmeier, Programmer at HASE Kaminofenbau GmbH

The stove manufacturer could now produce up to 25,000 stoves per year, compared to a maximum of 15,000 previously. “The two high-end robot systems are the greatest welding innovation we have ever had,” summarizes Fischer. “The most difficult thing about automation is finding a way to cover a broad product portfolio at the same time. We successfully solved this challenge together with KUKA and Paul von der Bank GmbH.” The secret of the project’s success is also rooted in its collaborative nature: KUKA offered HASE an all-round package and developed a custom-tailored solution on site together with the customer and the system partner.

Automation as an opportunity

In view of the increasing shortage of skilled workers, the employees at HASE also see the automation solution not as a threat to their jobs, but as a way of securing the viability of their employer. HASE plans to continue its balanced approach, combining traditional craftsmanship with cutting-edge automation. The company is already collaborating with KUKA on new concepts for automated edging, painting, and the welding of assemblies. The goal: to ensure the continued production of clean, modern wood-burning stoves – bringing even more crackling coziness into living rooms.