36 n PRECISION ENGINEERING October 2023 www.drivesncontrols.com Mobile robot modules can be swapped in less than a minute The German robot and connectors manufacturer Stäubli has used some of its own technologies to build a pioneering production line in which mobile assembly modules equipped with robots can be docked with the line in less than a minute to allow for changes in production. The line uses other advanced technologies including a Beckhoff XTS linear transport system and a robotic tool-changer which operates with a precision of ±1.5μm and eliminates the need for time-consuming manual changes. The line, at Stäubli Electrical Connectors’ factory in Weil am Rhein in Germany, marries sockets and plugs with the company’s Multilam contact technology, which comes in many variants. Initially, there was scepticism about whether it would be possible to dock the mobile assembly modules including robots with all of their complex peripherals, with the line within a 1-minute time limit, and then to start production without first having to calibrate the robot or to make other adjustments. But John Dallapiccola, managing director of the plant, and his team were confident that it could be done. The mobile modules had to dock into the line with precision of better than 0.01mm. The specification called for the modules to be positioned manually, centred automatically, then locked into place and set to work, with production start-up taking less than 30 seconds. During this period, the energy and compressed air supplies would have to start flowing to all of the module’s components. The robot, parts feed, separation and image processing, as well as the power, signalling and pneumatic connections for each component, would need to be connected reliably and simultaneously. To achieve this, Stäubli chose one of its own CombiTac modular connectors, which connects all of the power and media circuits automatically during the docking process. Precision mechanical guides and a pneumatically actuated quick coupling supplied by Stäubli Fluid Connectors ensure that the mobile module is positioned correctly. At present, the assembly line consists of 12 modules that are linked to each other by a Beckhoff XTS linear transport system. Four more modules will be added later. The transport system uses 20 magneticallydriven movers which travel along a track containing integrated motor modules. An industrial PC running Beckhoff’s TwinCat automation software controls the movers independently with individual motion profiles, operating with a precision of 0.01mm. The movers carry fixtures specific to different parts. The line incorporates five Stäubli Scara robots – four with six axes (TX2-60 models) and one with four (TS2-40). Two of the six-axis robots on the first two modules marry a Multilam connector with a plug or a socket, depending on the variant being produced. “Gripping and positioning these miniscule components with dimensions in the millimetre range requires the highest precision from the two TX2-60s mounted on their mobile modules, and it also has to be done with maximum dynamics,” explains production manager, Sebastian Wiech. “The six-axis machines perform this demanding task with aplomb.” Asyrill vibration platforms with image processing systems mounted above them supply the parts and ensure the transmission of gripper positions to the robots. The components then reach a processing station where the connector is united with the socket or plug. Depending on the variant, further work steps follow. If, for example, a socket ring has to be fitted, this is done by a compact four-axis robot. Every connector undergoes 100% quality control. “Ensuring product quality is one of the most important tasks performed by this A pioneering production line in Germany is using mobile robot modules, which can be docked in less than a minute, to cater for changes in production. The line uses other advanced technologies including a linear transport system and a robotic tool-changer. The mobile assembly modules can be docked manually and are immediately ready for operation
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