Comparative study proves energy efficiency and cost savings with electromechanical joining systems

The researchers examined the NCFE electromechanical joining module, designed for simple, cost-sensitive joining processes from Kistler, and comparable joining systems with hydraulic and pneumatic drives respectively, for the comparative study. All systems performed with force
of 15 kN.

The electromechanical system from Kistler operated at a speed of 180 millimeters per second. As the hydraulic and pneumatic systems cannot reach these speeds due to their pump capacities and pipe diameters, they ran at their respective maximum speeds: the pneumatic system achieves approx. 50 millimeters per second, while the hydraulic version reaches 65 millimeters per second.

Energy loss in pneumatic systems

“The conversion of electrical energy into compressed air energy inevitably results in losses,” says Prof. Dr.-Ing. Udo Triltsch, Professor for Mechanical Engineering at Ostfalia University of Applied Sciences. “The more inefficient the compressed air system, the higher the losses: these different energy losses must be taken into account when calculating the energy cost of pneumatic joining processes. To that end, we differentiate between various compressed air generation systems in this study: very efficient compressed air generation systems with efficient pneumatics which require 100-watt hours to generate one cubic meter of compressed air, systems with average or normal pneumatics which use 175-watt hours for the same amount of compressed air, and finally systems with inefficient pneumatics which use 250-watt hours. This allows us to represent realistic industrial conditions.”

Higher energy efficiency of electromechanical joining modules

Taking these assumptions into account, the researchers calculated the required joining stroke energy consumption of the different joining systems. The results show that the electromechanical joining system (servo press) from Kistler consumes significantly less energy than the other systems during the test (see Fig. 2). “The results clearly demonstrate the efficiency benefits of the electromechanical system,” says Nanno Peters, Dipl.-Ing. (FH) at the chair.

Based on the energy consumption (Figure 1), the university also calculated the annual energy costs for each of the joining systems. They assumed a total of 260 working days per year and a daily operating time of eight hours, the equivalent of 6,000 operating hours, as well as the average price of industrial electricity costs (in 2022) per kilowatt hour. Here too, the results clearly show that the highest cost savings can be achieved with the electromechanical joining systems from Kistler.

Providing future-proof solutions for a sustainable production and savings on operating costs

Alexander Müller, Head of Business Center NC Joining Systems at Kistler, draws a positive conclusion: “We are of course very pleased with the results of the study. They prove that we offer future-proof and sustainable solutions. The ecological footprint is a crucial parameter in production. Therefore, we offer our customers joining modules and solutions that combine cost-effectiveness, sustainability and efficiency. When users switch from a pneumatic system to an electromechanical solution, for example, they can reduce their energy consumption by up to 93%. They also benefit from lower overall operating costs – after all, they also save on procurement and operating costs if their joining system is configured according to the application. In that case, both maintenance costs and CO2 consumption are proven to be lower in the long term.”