Sales of robots are rising, especially for CoBots, those that work alongside humans to improve efficiency and reduce the burden on people. The robot arms that are available from MBO and Heidelberg for loading pallets are examples. In 2018, sales of robots increased 23% compared to 5% for other robots.
Because most of these robots are small, slow and have limited capacity in lifting, they can be operated without the need for safety cages. All this has been spearheaded by Danish company Universal Robots which provides different sizes of robot along with straightforward programming.
It does not mean safety is ignored. There is proximity sensing which stops movement if someone comes too close, picking up again when that person is at a safe distance. Clearly productivity will be affected if people are wandering too close too often so some kind of physical barrier will help. Some CoBots of very limited power and speed can come into contact with people without causing harm, but these will have limited applications.
It is also possible for large and high speed robots to work in fence free areas, if the robot is stopped by a light beam safety curtain. Assuming that this is not a frequent occurrence, such robots can be more effective than the safety first CoBot installation. It can also be less expensive: a Universal Robots CoBot able to handle a 10kg load will cost more than a Yasakawa robot with a 12kg capacity and safety curtain, which offers twice the capacity thanks to its speed.
In print the first robots have been those from Rima, such as the robotic palletiser installed at the end of high speed web offset presses to load logs of folded sections ready for the binding line. Similar machines can be seen at the end of high speed carton glueing lines. These have needed to be caged off.
Now CoBots are appearing as part of a folder. The MBO CoBo Stack has been well received as it reduces stress on operators. But is not really collaborative. It means that the folder can run without an operator, but it is a fence free option, which is important.
Robots are also used to load large format sheets to high speed inkjet printers, from the likes of Inca, Durst, Agfa or SwissQPrint, which calls its system Rob. These relieve the operator of having to mount the sometimes awkward sheets on the bed and so keep the printhead moving at speed. The gain in productivity is immediate.
However, Rob is a CoBot which limits its effectiveness in reaching across the largest tables. A conventional robot system with light beam curtain, as used by Inca, would be more effective as operators only venture close to the robot when changing pallets of material.
Nevertheless CoBots are rapidly gaining acceptance because without the fence the automatic assistant appears less daunting and is considered user friendly. Now the producers of more powerful robots are taking their cue from this and are working on ways to ensure the safe operation of their machines without the need for cages. When that happens, the market could shift rapidly.
Key to this will be making programming simple. This is another reason for the appeal of Universal Robots, and like the first smart phones the attractive user interface instantly makes previous generations appear out dated. The Universal Robots machines are programmed using a tablet, but what they can do is limited. This may be perfectly acceptable for many applications in print. However, as printers need to cope with an increasing complexity of jobs and workflows, this could be a limitation. A company like Graphic Robots will take a commission to automate one part of the workflow, but will find that when analysing the issue it may become far more complex.
“The only approach to a successful development of a robot application is to study it very, very carefully before selecting the appropriate robot, not the other way around. If the application turns out to be complex, a robot with a powerful controller as well as complex programming is required, so then it is time to consult professional robot application developers with knowledge within the specific industry. Anything else could end up being very expensive,” says founder Henrik Christiansen.
One approach is investment in a hybrid robot, that can be configured as a CoBot or can work as a high speed robot when needed. It is also essential that someone in the company understands how to programme the robot. AI set up is not going to cope with all the complexity of print and paper, and it is impossible to think of all the possibilities ahead of time. There will always be exceptions that call for intervention.
Graphic Robots has managed this by creating a series of standard program templates with the operator using a touch screen to enter the parameters for a specific job. Christiansen adds: “It also means that the total robot cell can be run via a separate screen or via menus on the production line’s operator screen, which makes everything more integrated.”
Most CoBots are small, slow and have limited capacity in lifting, so can be operated with proximity sensors to stop movement if someone is too close. However, this means productivity will be affected if people are wandering too close too often.