Robotic welding sets up small-batch manufacturer for future growth

Situation

Anton Paar GmbH manufactures high-precision devices for density and concentration measurement, rheometry, and the analysis of dissolved CO₂. Until recently, all components produced at its Graz, Austria, facility were welded by hand, as the company deemed robotic welding systems uneconomical for its small production runs of one to 400 pieces.

But ongoing sales growth, the increasing shortage of skilled workers in the domestic job market, and new robot developments that make automated welding more economically viable for small batch sizes prompted the company to consider the technology once again.

Anton Paar’s requirements made designing the system especially challenging. The company wanted flexibility in terms of the number, shape, and size of the components; different gripping, positioning, and storage possibilities; the option to use different welding processes (TIG and MIG) on a single component; and the ability to use forming gas to protect the components against tarnishing, which is necessary for cylindrical bodies. Also, once set up, the system needed to be able to process a complete order from start to finish in a single pass, without the intervention of welding specialists.

Resolution

“In close cooperation with our technicians, the welding automation team [at Fronius] developed a robotic welding cell that meets our requirements in every respect,” said Daniel Moik, department manager for joining technologies at Anton Paar. “On top of that, Fronius is ready to work with us to evolve the system and adapt it to new needs.”

Dominik Santner, COO at Anton Paar GmbH, said, “The new robotic welding cell represents a huge step towards automation of our manufacturing. If we were to weld our process sensors manually like before, we would encounter huge difficulties achieving the planned quantities in the coming years.”

New welds are programmed offline, away from the welding system, rather than directly on the system. This allows welding to continue during programming, which helps increase productivity. The welding technicians create these conditions by importing the CAD data of the measuring device components to be welded into the Fronius Pathfinder. Various joining scenarios are then tested, and welding sequences are defined and optimized during simulations.

Starting points, torch work angles, torch offsets in the corner areas, and all reorientations of the welding robot are taken into account during these simulations. Pathfinder identifies instances where the robot’s axis limits are exceeded. Software operators can then correct the storage location of the workpiece and position it within arm's length of the welding robot to prevent potential collisions between the torch and various component edges.

If the path needs to be corrected, the affected teach points can be moved by dragging and dropping. When the approach to the component needs to be changed, the operator simply presses “reset,” and the virtual robot moves to the home position to start a new approach run.

Once a welding program has been set up in Pathfinder, it is translated by a postprocessor into the specific code of the FANUC welding robot. It can then be transferred to the welding system via data transfer using a LAN connection, for example. The “determination of cycle time” function, which includes welding speeds as well as gas preflow and end crater filling times, supports production planning as a whole. Compared to teaching with the robot controller, Pathfinder can achieve a time savings of up to 90%, depending on the component geometry and welding requirements.