Stäubli six-axis machine automates sausage slicing

When it comes to handling 12kg sausages, the full-range food retailer Kaufland is breaking new ground. Recently, a Stäubli TX200 HE six-axis crane has been used to load an automatic slicing and packaging machine that prepares delicious cold cuts from 1.5m long sausages. The robot solution, which is believed to be unique in the world, relieves the burden on employees and brings other decisive advantages.

In the food industry, the use of robotics always faces special challenges when it comes to handling unpackaged food. If the robot comes into direct contact with the product, in this case sausage calibers, the strictest hygiene standards must be observed. What’s more, the disinfection processes that occur several times a day, as well as intensive washdown cleaning of all plant components, which are customary in the industry, pose almost insurmountable hurdles for standard robots.

The people in charge at Kaufland Fleischwaren’s sausage factory in Heilbronn also knew this. On the one hand, they saw the great advantages that could be gained with the use of a robot, but at the same time, doubts about its suitability clouded the investment decision. Dieter Schäfer, Team Leader Packaging at Kaufland Fleischwaren, recalls: “Loading a slicer with 1,500mm long sausage calibers weighing twelve kilograms over an entire shift was one of the rather unpopular activities for the employees. With the conversion of production to even more efficient processes, this work was also almost impossible to do manually. The robot seemed to be the right solution, but we were skeptical about whether a six-axis crane would be able to withstand our cleaning cycles in the long term.”

Reliable robot use under extreme conditions

Martina Düngfelder, Local Head of Life Sciences & Food at Stäubli Robotics, set herself the task of dispelling these doubts: “I was familiar with Kaufland’s reservations from numerous other projects. However, they were easy to get rid of, because our washdown-capable HE robots are considered a reference for use under the conditions mentioned above and have been proving their durability under hygiene-sensitive conditions for around 15 years.”

To be able to see this for themselves, Stäubli accompanied the Kaufland managers to a number of reference projects, including in the cheese industry, where Stäubli robots are already firmly established and function reliably for years under the strictest hygiene requirements. This dispelled doubts about hygiene standards and resistance to intensive cleaning, and Kaufland finally opted for the robot solution.

Space conditions and gripping technology as a challenge

With bsb robot systems GmbH from the Stäubli partner program, the right plant manufacturer was quickly found. The Aschaffenburg-based company has a wealth of experience in robot automation and was happy to take on the project. What initially sounded like a simple task – picking up four sausage calibers at a defined position and then handing them over to the slicer – turned out to be a challenging project on closer inspection.

Managing Director Rainer Bonfig sums up the special challenges: “The daily cleaning procedures were not the problem. We know that the Stäubli HE robots can handle this without any problems. Rather, we were concerned about the limited space available and the gripping technology, which was supposed to handle the sausage calibers safely and gently at the same time.”

Robot-assisted slicer loading

Since Kaufland is probably the world’s first to feed a slicer with a six-axis robot, it was not possible to fall back on familiar solutions from previous projects. The easiest way was to choose the right robot. Due to the disinfection and washdown cleaning processes, only a fully encapsulated, waterproof Stäubli HE robot was considered. And the factors of payload and range clearly spoke in favour of the choice of the large TX200 he, i.e. the specially encapsulated Humid Environment version.

This versatile, top-of-the-range industrial robot is one of the fastest on the market and sets standards in terms of hygiene, robustness, dynamics and precision. Equipped with a high level of cleanroom capability, the TX200 impresses with internal media and supply lines and a fully sealed housing with IP67 protection. In addition, interfering contours and dead spaces are systematically minimized. The housing is made of corrosion-resistant materials, so that the robot cannot be harmed by disinfection or washdown intensive cleaning. In addition, this model, like all other Stäubli robots, allows the use of food-grade NSF H1 oil without sacrificing performance or speed.

Design par excellence: the gripper

When designing the gripper, the bsb designers benefited from their decades of expertise in special machine construction. The solution found deserves the title of Masterpiece. The special feature here is that in order to achieve the specified cycle times, four sausage calibers have to be gripped at once.

In order not to injure the sausages during the process, bsb has come up with a special solution: “We have designed and built a so-called quadruple roller gripper, with which the Stäubli TX200 six-axis crane travels under the four provided sausage calibers at the transfer position and lifts them in a gentle manner. The gripper, which weighs just under 80 kilograms, is 1,800mm wide in total and has four rollers for each of the four calibers driven by a central motor. With the four support points arranged at an even distance, we ensure a secure pick-up and prevent the 1,500mm long, “bend-flabby” sausage calibers from sagging,” says Rainer Bonfig.

To load the slicer, the Stäubli TX200 precisely controls the transfer position. Once the final position has been reached, the central motor sets the rollers of the gripper in motion. In this way, the valuable cargo enters the slicer feeder in a reliable and precisely positioned manner. To prevent the sausage calibers from slipping through on the 3D-printed rollers of the gripper, they are provided with a fine hedgehog contour which provides the necessary traction during transport.

High output: 6,000kg of cold cuts per shift

With this automation, which is unique in the world, Kaufland’s Heilbronn meat plant achieves an output of 12,000 kilograms of cold cuts per day in two-shift operation. A total of 21 different types of sausage pass through the system, which are combined in four different sliced meat packaging units and are offered in Germany and Eastern Europe.

After initial misgivings, Dieter Schäfer is now completely convinced of the robot cell: “The Stäubli TX200 he six-axis robot was able to completely dispel my concerns about compliance with our high hygiene standards. The robot solution also fulfills our other goals one hundred percent. The reduction in the workload of the employees, the reliable work in confined spaces, the increase in productivity, the high availability, the robot’s resistance to the washdown intensive cleaning, the new, exciting work content provided by the robotics – the project is a complete success in all respects.”

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