October 2019

39 www.drivesncontrols.com October 2019 MACHINE BUILDING n A close-up view of some of the 32 movers and the guidance system incorporated into the cartridge-packing machine The modular operating mode selection and access permission system PITmode fusion combines safety and security in one system. The coded RFID transponder keys ensure that, on flexible machines where multiple users switch between di erent control sequences and operating modes, only those authorised and safely trained to do the task can gain access. Safe & Secure Machine Access ... Pilz Automation Technology Corby NN18 8TJ 01536 460766 sales@pilz.co.uk www.pilz.co.uk For further information about the PITmode fusion System from Pilz: Visit www.pilz.co.uk and enter Webcode 150439 or simply give us a call! Modular  Secure  Safe  Simple & Intuitive  Connected Safe and smart automation solutions that enable the intelligent production of the future – talk to a Pilz expert today! ... we‘ve got it covered clothoid-shaped end-segments. Unusually for this construction, the trays are not mounted directly to the movers, but are supported by a baseplate and pushed from one position to the next by pushers mounted on each mover. To facilitate this construction, the guidance system was mounted on an oversize baseplate, making access to the guide rail and three- bearing movers difficult. This is one reason why it was important for the system to operate for long periods before any readjustments or maintenance were needed. To make this easier, an automated lubrication system was integrated into the guidance system. The designers wanted to ensure the three-bearing movers would not need to be readjusted for as long as possible. "With the long pushers on each mover, the centre of gravity is relatively far from the centre of the mover,”Mulder explains. “Combined with the speed of movement, this applies a torque to each mover, which presents a major challenge in terms of the usable life of the guides.” “We needed to adjust our performance and lifecycle calculations to make accurate product lifetime predictions,” reports Jason Cox, technical sales manager at HepcoMotion, who oversaw the project. “To achieve the maximum service life, we tested a number of different motion profiles and designed the baseplate in close consultation with Smart Automation," Cox adds. “Normally, we would reduce acceleration to extend the lifetime of our V-guides, but the unusual design of the application and the frequent start/stop movements meant we needed to rethink this.” The answer was to maximise acceleration and to reduce the top speed of the movers. This reduced the centrifugal loads which, in turn, extended the life of the V-guides. The optimal top speed was found to be 2.13m/s, with a load of 0.293kg and pusher finger length of 52mm. "While Hepco initially sought a ten-year lifetime for its V-guides, in the end we had to settle for five years because the resulting moment load on the system was high,” Mulder explains. “Whilst this is less than initially sought, it is suitable for our needs.” The machine took 18 months to build – much longer than usual. “For me, time is not the most important factor, but the quality and the guarantee that it works,”Mulder says. “The machine has been with the end-user for a year now and works to their complete satisfaction. “We learned a lot from the project,” he adds, “and whilst there are some aspects we would approach differently a second time round, we are very satisfied with the overall result”. n