Final packaging of medical-technical products with support from robots
21. August 2019
The number of patients requiring dialysis treatment throughout the world is constantly rising. The figure is set to increase from 3.2 million people worldwide at the end of 2017 to an estimated level of almost five million by the year 2025. This trend is attributable not only to an ageing population but also to an increase in the number of people suffering from high blood pressure and diabetes – often the early warning signs of terminal kidney failure. As a result, the demand for dialysis products is very likely to keep on growing, and it is against this background that Fresenius Medical Care has become intensively involved in this market.
Just how large this demand has already become is clearly evidenced by the end-of-line packaging system that has gone into operation at the Fresenius site in St. Wendel in 2019 and which displays an impressive output level of close to 300 disinfecting caps per minute. When it came to finding someone to implement the complex packaging line, Fresenius turned to the packaging technology specialists – PKM Packaging.
A challenging task
The company based in Pirmasens is one of the top addresses for intelligent automation solutions and focuses in particular on the medical, pharmaceutical and food industries. PKM develops and engineers custom solutions that display a maximum level of productivity for applications that do not readily lend themselves to economic automation using standard systems.
In this case, the job was first of all to pack 300 dialysis caps per minute – which are fed into the packaging system in blister packs via five feed conveyors – into so-called dispenser boxes. Ten of these dispenser boxes are then placed in a shipping carton. What sounds simple at first quickly reveals itself as a major challenge once you realise the cycle times involved.
Peter Dreher, head of sales at PKM, looks back: “The problem was a combination of two factors: time and complexity. The system has to place the blister packs into dispenser boxes. These are only available in the form of blanks, and they still have to be glued, folded into shape, printed and labelled. At the same time, the shipping cartons have to be fetched, filled with the dispenser boxes, and sealed. And that was not all – it was also necessary to integrate a large number of scans and camera-based test stages into the line.”
Proof that PKM has indeed succeeded in finding a solution that is process-secure and at the same time highly economic – despite these exacting requirements – can be seen from the end-of-line packaging system, which – bearing in mind the complexity of the tasks it performs – takes up a surprisingly small amount of space. The system contains a total of five YASKAWA robots, operating in close proximity to each other; these comprise four identical six-axis MOTOMAN GP12 robots and one MOTOMAN MPP3 delta robot. While the six-axis units are responsible for all the carton handling operations within the system, the ultra-fast picker is responsible for taking up the blister packs and placing them in the dispenser boxes.
Operation of the end-of-line packaging machine
The sophistication of the system is clear from the complexity of the process in practice. This begins at one side of the machine, where the blanks for the dispenser boxes are fetched. The process centres on a MOTOMAN GP12, which is fitted with a suction cup gripper; this takes the blanks one at a time from the magazine and moves them to an image processing stage, where they are checked. The robot then takes the box to the next stage for gluing. The six-axis robot pushes the blank into a forming tool which folds it into the right form, and places the finished dispenser box on the conveyor belt below.
A second robot then picks it up and controls a Wolke printer, which prints a barcode onto it. A label is also applied at this stage. The MOTOMAN GP12 now moves the empty dispenser box to a stationary image processing system, which checks the barcode and label. The carton is now ready to be filled, and so it is cycled on to the key stage of the entire system.
High speed blister packaging with two robots
The packing sequence for the blister packs involves two MOTOMAN robots, one six-axis unit and one picker, working hand in hand. “This stage is equipped with two holders for the dispenser boxes, which means they can be filled alternately and the picker can operate continuously. This is what enables us to comply with the required cycle times,” emphasises Dreher.
The MOTOMAN MPP3 is fitted with a quintuple suction pad, which enables it to simultaneously take five blister packs from the five-track feeder and put them through a complex sequence of motions that ends with their placement in the dispenser boxes. This process is repeated by the delta robot a total of eight times, until the dispenser box has been completely filled with 40 dialysis caps. The system’s impressive output is down to the enormous speed of the MOTOMAN MPP3.
Working in parallel with this, the six-axis MOTOMAN GP12 operating in this stage is busy providing empty cartons for the picker as well as picking the filled dispenser boxes, which it feeds to a carton sealer by way of a special interlocking gripper. This is followed by an in-process control sequence. The sealed and finished cartons are discharged from the sealing unit and grouped into five rows of two each. The configuration of the ten dispenser boxes corresponds with one layer in a shipment carton.
The final step is to pack the dispenser boxes into the shipment cartons, and this is done by the fourth MOTOMAN GP12. The six-axis robot fetches an empty shipment box and takes it to an image processing system, which performs a check to ensure that the adhesive label is present. This is followed by the filling process, in which the robot takes up ten readied dispenser boxes using its vacuum suction cups and places them into the shipping boxes from the top. This cycle is repeated three times, before the shipment box with 30 dispenser boxes, each containing 40 dialysis caps, is ejected from the system.
Maximum availability and output levels
Despite their complexity, which has only been described in part here, the end-of-line packaging machine must be capable of fulfilling stringent requirements in terms of availability. “To ensure that the system is able to operate at maximum speed at all times, we have used only the best available components in the machine. For the robots, we chose YASKAWA, not least because we were already highly satisfied with their performance. They are fast, precise and reliable, and that is exactly what we wanted for this application,” says Dreher.
And it was a good decision, as we can now see. The machine is in constant operation throughout all three shifts. It has never suffered from any operational disturbances. The end-of-line packaging system fulfils the operator’s exacting requirements in every other respect too, in particular its high output speed. And this is no surprise, as YASKAWA already supported PKM with reliable real-time simulations and cycle time studies during the engineering phase. “Together we are strong and we can achieve just about any goal, something that this groundbreaking solution amply demonstrates,” concludes Dreher.
Author: Ralf Högel, Industrie Kommunikation Högel, Stadtbergen
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