New materials, new opportunities

As a technology partner in various areas of the plastics and packaging industry, KIEFEL GmbH now supports its customers in the development of biodegradable materials and products.

With Fiber Thermoforming, KIEFEL has opened a complementary field of technology utilising natural fibres, incorporating decades of knowhow from plastics processing into the development of the Fiber Thermoforming machines.

In addition to classic recyclable plastics, the company can now process fibre-based, recycled and bio-based materials. Virgin fibres (unprocessed cellulose) can be used to comply with food industry regulations for packaging solutions, meaning KIEFEL can provide the optimal product development and production technology, regardless of the material.

The raw material for fibre products is pulp or paper dissolved in water. This is shaped, pressed, dried and converted into dimensionally stable packaging that can be recycled or composted. Depending on the application, they offer an alternative made from renewable raw materials, with a low CO2 footprint. The Fiber Thermoforming process enables high-quality products with perfect rims and geometry tolerances similar to plastics.

This is enabled by an extensive fibre packaging machine portfolio: The NATUREPREP KFP series for high-quality natural fibre pulp stock preparation, and the NATUREFORMER KFT series systems, on which various fibre products can be manufactured. Matching coating concepts make the products grease- and water-repellent and barrier properties can be easily reached utilising sustainable materials that can be added to the pulp or coated onto the products.

Discovering the potential

In its Material R&D Center, KIEFEL researches, analyses, and categorises wood-based materials and designs coating concepts for natural fibre packaging. The company also investigates promising annual plants including wheat, straw and sugar cane. These are tested on pilot systems and optimised for the manufacturing process. The Material R&D Center complements KIEFEL's Applied Polymer Research Center, which focuses on research into recycled and bio-based plastics. In the adjacent Packaging Technology Center, the company undertakes testing on materials, tools and prototypes, as well as on machinery and small batch sample production.

The engineering in Fiber Thermoforming

The NATUREFORMER KFT series batch-processes raw cellulose pulp to a one per cent fibre content. Flow simulations ensure the fibres are evenly distributed. The aluminium suction tool is immersed in the suspension where the applied vacuum removes liquid, leaving the cellulose fibres in the tool, like a filter cake. A spray bar removes excess pulp and defines the edge of the product at regular intervals.

The suction tool then moves into a flexible counter tool in the pre-pressing station. These steps increase the dry content to approximately 40 per cent, guarantee even fibre distribution across the tool geometry, offer excellent dimensional accuracy and leave a very high-quality surface.

The suction tool then transfers the component to the hot press where any remaining moisture is eliminated by temperatures around 200°C in the upper and lower tools and a clamping force of up to 600kN. Richard Hagenauer, Head of the Fiber Thermoforming project, said: “Our technology allows us to achieve drawing depths of up to 250mm on the NATUREFORMER KFT 90 Flex. We work with cavities directly heated by heating cartridges integrated into the tool. This enables us to achieve optimal heat transfer, reduce energy consumption and achieve high product quality."

Fast tool change and machine handling

The suction tool is mounted on the handling robot and transfers the component from station to station. The KFT 90 Flex is equipped with a fully automatic rapid tool change system that enables the heated tool to be changed within 15 minutes. The handling robot traverses to tool positions for maintenance, cleaning and tool change. As on the plastics thermoforming machines, the KMI 2.0 HMI supports the machine operator, facilitating easy and transparent control.

Automation and Quality Management

The NATUREFORMER KFT series has a high level of automation that supports customers for industrialised production systems. Automation solutions include a tilting and stacking function, Flex-Picker, sleeving station and automation up to and including packing. Quality control and inspection systems can be integrated, as well as peripherals for printing and labelling. The various automation modules and their connectivity enable KIEFEL to meet specific customer needs.

The machines are experiencing high demand – several have been delivered with many more on order. This makes KIEFEL the first manufacturer of plastic thermoforming machines to also offer highly automated systems for fibre thermoforming.