Thermoforming meets fiber
Kiefel GmbH, Freilassing, is a technology partner in various domains of the plastics and packaging industry, where it supports customers in the development of sustainable materials and products. In addition to classic recyclable plastic, Kiefel systems processes recycled (e.g. rPET) or bio-based materials (e.g. PLA).
“More and more customers are asking us about technology that they can use to produce high-quality cellulose-based packaging. Our fiber thermoforming systems provide a solution that complements plastic processing,” says Erwin Wabnig, Head of Fiber Thermoforming, describing the evolution of the new machine “Natureformer”. This enables Kiefel to provide the right machine technology – whichever material the customer chooses. With fiber thermoforming, the company has opened up a complementary technology field with a new material – incorporating decades of thermoforming machine design know-how.
Machine under the microscope
The raw paper pulp is processed in batches up to 1% fiber content. Flow simulations ensure that the fibers are evenly distributed over the basin volume. The metal mesh suction tool dips into the slurry, the vacuum sucks up liquid and leaves the fibers in the form of a filter cake in the tool. A spray bar cleans the edge of the tool and removes excess pulp. The suction tool then moves into a flexible counter tool of the pre-pressing station. Alexander Huber, Fiber Product Manager, illustrates: “The flexible pre-pressing tool ensures very even fiber distribution across the entire tool geometry.” After this step, the fiber content reaches approximately 40%. The suction tool then transfers the component to the hot press. Any remaining moisture is eliminated by temperatures up to 200°C in the upper and lower tools in combination with a clamping force of up to 600 kN. Huber explains: “Our technology allows us to achieve product heights up to 250 mm. We work with cavities which are direct heated by heating cartridges. The heating cartridges are integrated in the hot-press tool. This enables us to achieve optimal heat transfer, reduce energy consumption and achieve high product quality.” The suction tool is mounted on the handling robot and transfers the component from station to station. Defined tool positions for maintenance, cleaning and tool change can be reached in this way. The Natureformer KTR 90 tool change is completed within 15 minutes thanks to the automated quick-change system. Kiefel adapts machine automation – stacking, sleeving, packing in boxes – to customer requirements. Quality control and inspection measures can be integrated into the machine via additional modules. A full scale pilot system is already running, producing Kiefel reference cups with a cycle time of 15 seconds. Huber emphasizes: “We now have numerous systems in our order backlog. We will deliver the first to a customer in the middle of this year.” This makes Kiefel the first plastic thermoforming machine manufacturer to offer highly automated systems for fiber thermoforming.
