LKH Injection Molding Technology: Less Energy – Higher Quality
LKH Injection Molding Technology Sustainably
Reduces Energy Consumption A few years ago, LKH Kunststoffwerk in Heiligenroth, Westerwald, installed a completely new, state-of-the-art injection molding system. A key component in ensuring long-term efficiency and quality was—and remains—a sustainable energy-saving concept that accompanies the expansion of production.
As a member of the Friedhelm Loh Group, which also includes Rittal, LKH produces complex and sophisticated plastic parts for electrical system engineering at its plant near Montabaur. Additionally, the company develops and manufactures such parts and assemblies for the automotive industry, equipment manufacturers, and other sectors.
Rüdiger Braun, Head of Sales and Engineering, explains that with the move to the new plant a few years ago, the company’s strategy was realigned even more clearly toward growth and a focus on high-tech components and assemblies, as well as high production efficiency. Accordingly, the company invested in modern injection molding machines, a centralized material supply system, and energy-saving technology. A key component of this: Thanks to the integrated concept of the Oni heat exchanger, cooling the injection molding machine hydraulics and the molds is significantly more cost-effective, and the waste heat is also used to heat a new logistics hall. Thomas Ritter, Head of Process Management, describes the impact of energy management on the quality of the injection-molded parts as a welcome “side effect”: “The high performance of the cooling technology and the consistent temperature under all environmental conditions significantly support quality and allow us to push the limits of the processing windows.”
The approximately 50 injection molding machines at the LKH plant, with clamping forces ranging from 250 to 16,000 kilonewtons, are connected to two cooling circuits, one each for mold and machine cooling. The waste heat from the machine cooling circuit is used to heat the logistics hall. LKH utilizes all these components within the integrated energy-saving concept designed and implemented by Oni. Integrated into the control system, Oni has also incorporated a chiller that was already present in a hall acquired and converted by LKH. It serves to ensure cooling capacity during periods of particularly high demand.
Save energy step by step
LKH has designed its infrastructure to accommodate growth. Accordingly, the installed cooling capacity was generously sized. Nevertheless, the system is not oversized. Depending on operating conditions, total energy consumption is always kept to a minimum—with a high degree of reliability: During the colder seasons, the two separate circuits for cooling machines and tools are cost-effectively recooled via idle free-cooling units. The hall heating system utilizes the waste heat from the machine cooling circuit, which is available at no cost. During the transitional period with higher outdoor temperatures and correspondingly lower heating energy requirements, the free coolers operate for machine cooling and the chillers for the tool cooling circuit. In summer, when outdoor temperatures are high, the free cooler for machine cooling is supported by adiabatic cooling, and in extreme weather conditions, the chiller covers peak loads.
All system components are networked via a single control system. Depending on the demand for cooling and heating capacity as well as environmental conditions, it ensures the optimal combination from a cost perspective at all times. The control interface allows LKH to make adjustments and optimizations on its own as conditions change and operational experience grows.
Cost Reduction and Certification
“We have a very precise understanding of the energy consumption of our machines and systems thanks to measurements and documentation,” explains Thomas Ritter. “This is the only way to ensure accurate cost calculations. Accordingly, we have also made ongoing improvements, such as insulating heating bands.” This cost transparency also enabled a realistic assessment of the Oni project plan—and the verification of the projected values during ongoing actual operation. Above all, heating the spacious logistics hall to an average of 18 to 20 degrees using only waste heat—even during the cold winters of the Westerwald—offers significant savings potential. Furthermore, with the constant changes to the machinery, minor improvements are always possible. “With an eye on the effects on part quality and specific energy consumption, we carry out minor optimizations ourselves, for example with temperature settings,” comments Thomas Ritter. “Incidentally, energy recovery via the Oni system to reduce energy consumption also helped us with our certification to ISO 50001 and ISO 14001,” explains Rüdiger Braun. Key performance indicators are derived from regular measurements on various machines and systems, such as the air conditioning, to continue reducing specific energy consumption and implement new ideas in the future.
These included, for example, the retrofitting of a conditioning cabinet in which LKH processes polyamides to meet particularly high manufacturing standards. This cost-effective approach to quality improvement and assurance provides a competitive edge. According to Thomas Ritter, a few photos of the installation site were all it took for Oni to provide a comprehensive plan for integration and an estimate of the expected costs within a single day.
Thanks to the completion of all projects on time and within budget, as well as the achievement of the energy savings promised during the planning phase, discussions are ongoing with Oni as a potential partner for future projects.
