Smart Molding International 2-2024

23 www.smart-molding.com machinery subsequently assembled manually, together with the electronic components supplied by the customer. As a central part of winch drives in crane systems, this assembly is an important safety feature. These devices known as geared limit switches control the positioning of the crane hook. Depending on the type and size of the crane, the crane hook must be able to carry loads of up to 120 tons reliably. Therefore, every geared limit switch is examined on a test stand for correct functioning and then provided with a code via which the test documentation and all subsequent servicing activities can be traced. Accordingly, the demands on injection molding processes for the individual components of the assembly are particularly stringent. “Drive systems only function if the cogwheels are kept strictly within tolerance limits”, says Langenberg. Multi-stage planetary gears, small axes and mounting elements for circuit boards and switches are molded mostly from two materials – ASA and POM. Inside the SmartPower machines, themain elements providing high process stability and reproducibility for even extremely delicate part geometries are high-precision injection units and a combination of fast-response servo-hydraulic motors with high-performance constant displacement pumps. Consequently, there is no more production scrap. The machines’ “Drive-on-Demand-2.0” technology also minimizes their energy requirements. During cooling and handling phases, the motor is shut off and consumes no energy. “Depending on the application, Drive-on-Demand 2.0 reduces energy consumption by up to 35 per cent compared to machines with modern variable displacement pump systems”, explains Daniel Müller, Regional Sales Manager at WITTMANN BATTENFELD in Germany. A further contribution to the high level of energy efficiency is made by the kinetic energy recovery system, abbreviated KERS, patented by WITTMANN. It transforms the deceleration energy of the moving mold platen into electric energy and transfers it to other consumers – for example the barrel heater. Plastic version tougher than hybrid part The KB Kunststofftechnik team members are particularly proud of their geared limit switches, since before the crane manufacturer placed the order in Gummersbach, this assembly was a hybrid object made of plastic and metal. “Jointly with our customer, we developed the thermoplastic variant further in order to exploit the advantages of the plastic material more fully”, reports Langenberg. “This proved a major success, since the parts’ unit costs were reduced and the drive systems now reach a longer service life.” For some other customers, too, KB Kunststofftechnik functions not only as a contract injection-molding business, but also as a co- designer of the products. “These are often companies thoroughly familiar with metalworking, knowing that we have a particularly thorough in-depth plastics processing expertise combined with extensive experience. Our strength is to recommend the most suitablematerials for a given application and to design the part to suit thesematerials”, Langenberg continues. On its own premises, KB Kunststofftechnik carries out simulations, strength analyses and FMEA, designs and produces the molds, makes prototypes and subjects these to endurance tests. As integrated complete solutions, the production cells have only a small footprint