CUPS DON’T NEED TO BE CRASH TESTED
A standard solution for vision inspection is to have the products pass the lens one at a time. Continuing one at a time they reach the stopping point at the end of the conveyor belt, where the product gets piled up pushed up from below. Finally, the pile is boxed for further transportation. The faster that process is, the more gently it must work not to damage the products. That’s one of the reasons we’re happy to know Hasse Beckhoff.
When 100 products per minute are handled on a conveyor belt – including inspection, piling and packaging – the balance between speed and safety is critical. Crashes are not allowed! That’s why we use a high-speed camera when adjusting the layouts of our automated production lines. For example, we can watch in minute detail when a lightweight mug hits the stopping barrier. It looks like a crash test of a car. The mug gets deformed on the side, and a piston comes from underneath, pushing it upwards into the stack. As we examine the process frame by frame we sometimes have to wonder if it’s going to work. In the end it always does. Correctly adjusted automation is pure magic.
Let’s call Hasse
One hundred products per minute doesn’t represent the maximum number of units that are possible to manage at the end of a conveyor belt. But when the packaging company Superfos wanted us to increase the speed to 133 paper cups per minute, we knew we were in trouble. The cups all had irregular shapes and weighed only 21 grams. A robot that could stack 133 sensitive paper mugs every minute without disfiguring them would be a personal record for us. We had to think differently. We had to call Hasse Beckhoff.
“As the trolleys stopped, crash tests didn’t come to our minds any more.”
Ditching the conveyor belt
We had to get rid of the conveyor belt, but what could we replace it with? The cups had to be transported in some way. Vision inspections still had to be included in whatever the new, unconventional solution was to be. The camera would need to view the cups from all angles, even the insides. We ruled out the idea of having a robot grab the cups, they were too fragile to tolerate such rough treatment. But with the help of our friend Hasse Beckhoff’s Extended Track System (XTS) we thought we might find a solution. It was possible that XTS could handle the cups one by one, really fast, without crushing them.
100 times faster and no more crash tests
XTS enabled us to place as many small trolleys as we wanted on a magnetic linear track where each trolley carried a single product. individually controlled. The trolleys are designed for the products to be viewed from all directions. Watching the cups stop on the trolleys, the stopping no longer reminded us of crash tests. The procedure was rapid, but without any violent impact. And since XTS works without rails, any product can be handled in this smart way, not just fragile ones.
Information for nerds
For many years now, Beckhoff has worked with PC-based control systems supporting more sources and increasing performance immensely. A traditional PLC delivers scanning speeds around 20 ms. Beckhoff makes us 100 times faster. Integrating with a parent business system is easy and makes the solution basically limitless. All in all we used seven servo engines, one XTS track with individually programmable trolleys (controlled in the same way as a servo axis), integrated safety and HTML-5 HMI on big screens.
Johan Rosell, CEO of Berry Superfos Mullsjö, describes the new project as follows:
“The desire to develop and constantly produce better products faster and more efficiently is a guiding star for us at Berry Superfos. Our collaboration with 3Button Group has been open and developing. We really feel that this is something we have achieved together. The opportunities with Beckhoff and their XTS course open up new ways of thinking and push the boundaries of how far we can go. Working with new technology in this way feels very developing.”