Mechanical Technology January 2016

⎪ Innovative engineering ⎪

All of Bosch Rexroth’s electro-hydraulics expertise is integrated into the IndraMotion MLC control solution software, which can replace elaborate programming with parameterisation.

Aventics AV valves are a valve technology innovation that is pushing the boundaries of electric/pneumatic hybrid products in terms of space and energy efficiency. ent loads could be chosen. A maximum load of 100 kg was used and standard hydraulic and pneumatic components used, with the electro mechanical actua- tor being an integrated actuator. The measured energy consumption was multiplied by the number of operat- ing hours and extrapolated to the real need during one year – with 6 000 hours per year taken as a basis. An air cylin- der’s energy requirements worked out to 8 980 kWh per year, hydraulic at 3 602 kWh for the same period and the electro mechanical alternative only 816 kWh. CO 2 consumption for the pneumatic system worked out to 5.3 tons a year, with 2.3 tons from the hydraulic system and only 525 kg resulted from the electro mechanical equivalent. Thus, a saving of 90% was achieved compared to the pneumatics-only system and 77% compared to the hydraulic cylinders. An energy consumption-based com- parison shows that hydraulic actuators needs 4.4 times more energy for the same duty cycle and a pneumatic cyl- inder needs 10 times more energy com- pared to electro mechanical actuators. The electronics in Aventics AV valves (mentioned under pneumatics above) in these applications support all standard fieldbus and Ethernet protocols, which realise control and communication tasks. The sensors also feature IO-link inter- faces, allowing them to exchange data with the control for diagnostic functions or parameterisation. For example, the Bosch Rexroth EMC electromechanical cylinder has an optional force sensor, which allows decentralised process controls without a higher-level control system. The EMC-HD is a powerful alternative to pneumatic and hydraulic cylinders and provides benefits in terms of en- ergy efficiency. It provides an advanced control technology advantage, even at

can be placed on machines close to the action, which can reduce compressed air consumption by up to 20%. Electric control Electric control excels when absolute ac- curacy of movement is required or when continuous motion is needed. Electric servo control is useful in such diverse applications as CNC spindle controls in machining centres and in lift-and-locate applications for assembly operations. Electronic servo control offers the highest levels of precision, particularly in closed-loop applications where feedback allows the system to adjust to conditions. For example, Bosch Rexroth offers the System 300 advanced DC tightening system, which allows for multi-stage programming and multiple synchronisa- tion of the spindle motors. Since hydraulic and pneumatic ap- plications use cylinders, they achieve linear motion simply and easily. Electric control is based on rotating motion and requires a transition, such as a ball screw or linear motor. As energy efficient technologies should be used more often, and pro- cesses improved, electro mechanical actuation should be considered as it can offer many industrial areas a bet- ter economic and energy use solution. An experimental analysis conducted by the University of Kassel in Germany incorporating hydraulic, pneumatic and electric actuators, proved that the latter are the most energy efficient across the three disciplines. In conducting the experiment, a spe- cific duty cycle was chosen and param- eters set for real application simulation. All actuators were mounted inline to have the same required duty cycle, the speci- fications for the choice of cylinders were similar, and the set up ensured that differ-

The EMC-HD electromechanical cylinder is a powerful alterna- tive to pneumatic and hydraulic cylinders that provides energy efficiency benefits.

high forces – force, position and speed can be free- ly parameterised – and its

flexibility means it can be adapted to new tasks via the drive system. It is an electromechanical heavy-duty cylinder that transmits motor movement via ball or planetary screw drives, depending on the dynamics and force requirements. Hybrid solutions There are a number of factors to consider when selecting technology for a specific system: accuracy and repeatability, ap- plication complexity, speed flexibility, reliability, maintainability and lifecycle costs. The convergence of production IT and business IT, the synchronisation of processes as well as decisions taken autonomously by machines in real-time, have enabled the Hytec Group, through its relationships with Bosch Rexroth and Aventics, to provide accurate, efficient, customer-specific manufacturing prod- ucts and solutions. Industry 4.0 and the resultant hybrid automation solutions represent better resource allocation, higher efficiency, individuality and profitability. The Hytec Group is Industry 4.0 ready, with a num- ber of safety-compliant hybrid solutions that integrate electric/pneumatics, elec- tric/hydraulics and now even pneumatic/ hydraulic/electric solutions. q

Mechanical Technology — January 2016

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