KraussMaffei Extrusion has developed a new 3-layer pipe head for PVC sewage pipes that enables safe and stable processing of up to 100% recycled material. The KM-3L RK 42-HP, to be presented at K 2025, is a ground-up design with a patent-pending flow system and symmetrical material feed to all three layers. The unit covers a processing range of 400 to 1,200 kg/h and pipe diameters from 110 to 250 mm, addressing large-scale industrial production. In the core layer, a highly efficient 1-to-8 distribution architecture shortens dwell times and reduces error susceptibility, supporting reliable use of recyclate whether the layer is foamed or compact and regardless of whether the source is in-house recycled material or post-consumer waste. The cover layers are optimized for efficiency and flexibility, and while virgin material is commonly used today, the design is also suitable for 100% recycled content. The new flow concept is intended to eliminate spiderlines, preventing material accumulation and turbulence so the pipe interior remains free of streaks. The pipe head dispenses with chrome plating and double compression, which reduces manufacturing costs, improves environmental balance, lowers thermal stress on the melt, simplifies cleaning and allows quick tool changes. These features are complemented by a wide process window aimed at long, stable production runs with minimal downtime.
Design features and process stability
The core of the KM-3L RK 42-HP is a high-precision, patent-pending flow system. Symmetrical feed to all three layers supports consistent layer formation, while the core layer’s 1-to-8 distribution reduces residence time, a key factor when processing sensitive or variable-quality recyclate. The flow geometry is designed to minimize stagnation zones, which helps prevent surface defects associated with uneven melt delivery inside the die head. According to the company, this configuration allows reliable processing of up to 100% recycled material in the core, whether compact or foamed.
Commenting on the development, Ralf Benack, CEO KraussMaffei Extrusion, said: "With the new KM-3L RK 42-HP, we are presenting the most advanced 3-layer pipe head for PVC applications. Our customers benefit from economical, sustainable, and outstanding quality pipe production."
Efficient and sustainable: The new 3-layer PVC pipe head enables the safe and stable processing of up to 100% recycled material, even with highly variable material quality.
Throughput, cost and operability
The pipe head’s processing range of 400 to 1,200 kg/h and its diameter capability of 110 to 250 mm target industrial wastewater pipe production. Dr. Thomas Unger, Vice President Technologies at KraussMaffei Extrusion, noted: "Thanks to the largest process window on the market, long production runs with minimal downtime are possible. At the same time, material costs are significantly reduced." Given that material typically represents the largest share of operating costs, even incremental savings can have a noticeable impact on total production economics.
The design eliminates chrome plating and double compression geometry. Avoiding chrome plating cuts manufacturing costs and benefits the environmental profile. Removing double compression reduces thermal stress on the melt, simplifies cleaning and supports rapid tool changes, which shortens changeover times in day-to-day operation. The system is intended to be easy to integrate, with maintenance and product changes kept straightforward to further limit downtime.
Surface quality and application scope
The new flow system aims to eliminate spiderlines, the fine marks that can appear on the inner wall of PVC pipes, by ensuring uniform melt distribution and avoiding turbulence and material build-up in the die head. With these measures, the KM-3L RK 42-HP is positioned to produce durable, reliable infrastructure components using recycled PVC while maintaining surface quality and dimensional consistency. Although virgin material is still commonly used in the outer layers, the head’s architecture allows these layers to be produced from recycled material as well.
Ready for use in modern piping systems: 3-layer PVC wastewater pipes made from up to 100 percent recycled material.
Exhibit at K 2025
KraussMaffei Extrusion will present the KM-3L RK 42-HP at K 2025 in Düsseldorf. Hall 15, Booth C24.
