Drives & Controls October 2022

n MACHINE BUILDING AND OPERATION Linear transport system assembles 40,000 fuse-holders a day T he German company Wöhner manufactures electrical products and switching systems for applications such as energy distribution, control technology and renewable energy. In less than six months, the company has configured and commissioned an automated line for assembling fuse-holders using a linear transport system. The line can assemble up to 40,000 fuse-holders per day in up to 94 different varieties. The transfer system is based on the principle of a revolving linear motor with vertically arranged workpiece pallets. There are 20 of these pallets which are channelled asynchronously through a series of processing stations in a highly dynamic way to achieve the shortest transport times possible. The motion profile of each pallet can be defined individually. The modular design will make future adjustments simple. The aim was to automate a part-feeding process, and to integrate this into the automated assembly of fuse-holders. The linear transport system – a Bosch Rexroth ActiveMover –accelerates the workpiece on pallets moving at up to 40m/s2 and can achieve high dynamics. The assembly of the fuse-holders has been designed so that the cycle time at each station for each component is less than three seconds. All of the assembly steps are checked automatically using several camera systems. The transfer system is connected to a supervisory PLC system via an open interface. The modular design of the ActiveMover makes it easier to adjust the hardware and software to handle new tasks so that other components could be manufactured with the same level of efficiency in the future. New target positions and movement parameters can be added using Rexroth’s AMpro (ActiveMover program) software which simplifies programming and system configuration. According to Andreas Friedrich, manager of Wöhner’s robotics and software development operations, the linear transport system will help the company to continue to manufacture in Germany. “It is only with the help of high productivity assembly systems that we will be able to manufacture our products in Germany in the long-term,” he says. n Although linear transport systems for production lines have been around for several years, not many actual installations have been publicised, partly because there are limited numbers of applications, and partly because many are shrouded in secrecy. However, details have emerged of a German installation that is assembling 40,000 fuse-holders per day. Wöhner’s fuse-holder production line can make 40,000 items per day in up to 94 different varieties.