Cobots from Universal Robots, supplied by the Polish distributor, ProCobot, with the Robotiq gripper that is available on the UR+ platform, were used for the automation. Bernacki started to introduce the first UR10e cobot in April 2019 and the machinery was equipped with further two cobots in the following months.
Each robot takes a component from a specially prepared pallet consisting of a pin grid, which enables the machine to correctly assess the position of the component and reliably pick each of them. The fingers of the robot gripper’s are 3D printed in-house, specifically designed to handle the components. After it is picked, the component to be machined is placed in the CNC.
The robot opens the door of the machine itself and places the component into the work space. In order to establish that the CNC is ready for successive operations, the cobot exchanges signals with the machine, making sure at the beginning that the machine is ready for insertion of the component to be machined into it. Communication between cobots and machines is carried out using the C-Interconector by CobotPlanet. The robot then precisely places the component in the spindle of the machine. The cobot gripper jaws, as well as its entire arm, have to move with a tolerance of just 0.5 mm to accurately put the component in place. After receiving a signal confirming that the component is placed correctly in the machine, the cobot leaves the work space, closes the door and sends information to the CNC that it can start its task. When the machine starts to operate, the cobot waits for another signal to inform it that the task has ended. It opens the door to the work space again, takes the finished, machined component and sends a jet of air in its direction to blow away the metal chips from the spindle. The finished component is placed precisely onto a specially prepared pallet. Taking into account all the requirements related to the movement of the robot in a human-safe environment, the whole cycle lasts approximately one minute.
"After several months of experience in working with cobots, we know exactly what should be done to best meet their role in our CNC production process. This work requires the highest precision and repeatability," says Nikodem Bernacki.
The whole workstation with the robot and the mount weighs about 60 kg – it can be moved by two employees. "Cobot is stably mounted, it can be easily transported, and the changeover and preparation for work in a new place takes only 20 minutes. It takes about an hour to fine tune the machine and robot and start production," says Nikodem Bernacki.
Currently, there are two operators working on each shift, handling the supervision and tending of 11 machines. Employees are responsible, among others for the changeovers of CNC machines, preparing parts, transporting them to and from the lathes, as well as programming and moving cobots between stations. "Our philosophy is to use the machine park to the maximum extent - cobots working in three shifts allow us to do so," says Nikodem Bernacki.