Cable guidance for pick & place robots: safely guided despite a rotating axis

Festo SE & Co KG is a leading provider of automation solutions for processes and entire production plants. The manufacturer's extensive product portfolio also includes its universal parallel robot "EXPT". The tripod-based pick-and-place robot works with high performance and precision, managing up to 150 picks per minute. Its design and control system enable flexible and cross-application use. This makes it easy to implement, even in applications with several robots in the production line.
An A5 axis was to be realised at the lower end of the robot, where the gripper is located, to enable fast and precise rotation of the gripper. A particular challenge here is the safe and gentle guidance of the cable to the rotating axis. This is because with a high number of cycles and continuous operation, 360° rotations in less than a second, speeds of up to 7 m/s and accelerations of up to 60 m/s2 , there is a high load on all cables, which can lead to high wear.

For the cable routing, we proposed a rotary energy chain, i.e. an energy chain with reverse bend radius and rotation module. To be more precise, the cables run in an energy chain from the E2 micro series. Running in a special rotation module, the energy chain can also achieve the desired high rotation angle.
The cable routing design offers several advantages for the pick-and-place robot: while the extremely low weight allows the robot to be highly flexible and move quickly, the failure rate of the cables leading to the A5 axis has been significantly reduced.
There was previously no solution on the market for such a cable feed to the rotary axes, which is why the development work between Festo's engineers and our cable specialists was characterised by a particularly close exchange. This collaboration also led to the selection of specific cables for this application. Among other things, the manufacturer relies on chainflex® control cable for high loads in moving applications. So that Festo can save on harnessing, the automation specialist has ordered the energy chain directly with the cable pulled in and ready for connection as a so-called readychain®.