February 2020

44 n ROBOTICS AND AUTOMATED MANUFACTURING February 2020 www.drivesncontrols.com Sensor-maker uses robot cell to adapt to varying batch sizes T he German sensor manufacturer Lenord + Bauer is using a robotic cell to optimise its production operations to allow for frequent product changeovers. The robot, which operates safely close to human workers, has taken over monotonous manual pick-and-place tasks at L+B’s Gladbeck plant in NorthWest Germany. Founded in 1965, Lenord + Bauer produces precision motion sensors, controllers and integrated drives. It manufactures products such as compact encoders for logging speed and position in dynamic systems, including machine tool spindles. It also specialises in sensors for use in packaging machines and railways. The company’s modular products are designed to be tailored easily for different requirements using customised cable assemblies and connectors. This results in a wide variety of batch sizes, ranging from single items to large-scale production runs. The high levels of customisation and the varying sizes of production runs presented a challenge for more traditional forms of automation. Set-up had to be fast and flexible, otherwise the automation would not be worth doing. The high variability of batch sizes makes frequent retooling necessary, as a result Lenord + Bauer wanted a robotic system that would deliver precision operation and allow re-programming to be carried out as quickly as possible. The company chose a Mitsubishi Electric RV Series six-axis articulated arm robot with a 4kg load capacity. This arm now carries out the required pick-and-place tasks to a positional accuracy of ±20μm. It is housed in a 4m 2 cell which can be moved using a pallet truck if required. This was made possible by using a CR750-D robot controller which can be installed in a 19” rack. Simple set-up and operator controls allow the cell to be used cost-effectively on a wide variety of batch sizes, releasing operators to perform more interesting and valuable work elsewhere in the plant. Along with the controller, the robot is equipped with a teach box that enables it to be programmed in a matter of minutes. Mitsubishi’s Melfa SafePlus safety system allows the cell to operate close to the human workforce. Two laser scanners on opposite corners of the square-footprint cell frame each monitor an area that is 180 degrees wide. If a person or object enters this safety zone, one of the scanners sends a signal to the controller in real time to reduce the speed of the robot to a pre-defined setting. If the person or object then encroaches further into the safety zone, entering the operating space or collision zone of the robot, a further signal stops the robot’s movements immediately. The frame of the robot cell is also fitted with a safety light curtain which sends an additional confirmation signal to the SafePlus system if an object is detected. With future production requirements in mind, Lenord + Bauer was keen to integrate the robotic cell into its higher-level systems such as ERP and quality assurance. As part of its policy of optimising production continuously, the company is planning to implement a Kanban warehouse for the sub-assemblies that it needs for the manual final installation process. A future-proof design was therefore important. As soon as sub-assembly stocks drop below defined minimum levels, the warehouse will communicate autonomously with the robot and production will be increased accordingly. The robots can be integrated easily into factory control and IT networks without any additional development work. Future developments planned for the Gladbeck plant include allowing the robot to take parts directly from stacking stations, and to use robots in other production processes such as soldering and laser-marking. n A German sensor-maker has installed a robotic cell that allows it to handle a variety of batch sizes from single items to large-scale production runs. The cell has been designed to integrate with the company’s higher-level enterprise systems and with future developments such as a planned Kanban warehouse. Lenord + Bauer can program its assembly robot within minutes using a teach box.