Saving energy does not only make sense from a sustainability perspective. They are also a significant economic factor, especially in energy-intensive sectors such as the plastics processing industry. In order to identify this potential, the SKZ Plastics Center held a workshop entitled “Saving energy in injection moulding” at hankensbütteler kunststoffverarbeitung GmbH & Co. KG (hk). The company employs 80 people and has 25 injection molding machines with clamping forces ranging from 35 to 350 t from various manufacturers. The aim of the workshop was to compare the different drive concepts of the machines and possibly reduce the energy consumption of the systems by adjusting the parameters.
On the SKZ side, the workshop was accompanied by electrical engineer Martin Winkler, who was responsible for measuring the current and evaluating the results. Injection molding technician Ulrich Schätzlein was responsible for the theoretical part and for selecting and setting the parameters on the machines. 17 people from the injection molding production, quality management and sales departments at hk took part.
The power consumption could be measured during the running process on the sub-distribution board of the entire machine (SGM plus peripherals) so that the series production process did not have to be interrupted during the tests. The products were spherical cups made of PA66 with 30% GF and covers made of PP with 15% GF. Depending on the article, a production time of 10 to 15 minutes was recorded and evaluated. The evaluation was carried out using the GridVis software from Janitza.
“For machines with hydraulic drives (clamping unit and dosing), savings of up to 15% could be achieved by simply optimizing the process parameters. In contrast, there were no significant changes to the parameters on machines with electric drives, as these machines have already been optimized using modern drive technology,” explains Schätzlein.
Kevin Ruschitzka, the setter responsible for sampling, added: “I will use the findings from the workshop for sampling in order to start with an energy-conscious process right from the start.”
Clemens Schulze, Head of Quality Management at hk, adds: “The savings achieved by changing the parameters were surprising for everyone. For me, the comparison of the drive concepts of the machines was interesting, a kind of “benchmarking of the machine park”.
Due to the many workshops in various companies, an online course was also created at the SKZ in order to efficiently show employees the theory and the simplest adjustment screws for saving energy and to convey possible solutions. Lukas Schmidt, apprentice, added very aptly in the feedback round: “Saving energy is interesting and fun.”
Further information on further training at: Online course: Energy efficiency in injection molding
The SKZ is climate protection company and a member of the Zuse Association. This is an association of independent, industry-related research institutions that pursue the goal of improving the performance and competitiveness of industry, especially SMEs, through innovation and networking.
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