Maag presents gear pump for rigid PVC extrusion

Maag Group has presented the extrex⁶ EC, a gear pump developed specifically for the continuous conveying of rigid PVC in extrusion. According to the Swiss machine manufacturer, the system addresses a long-standing technological limitation in PVC processing, where the material’s thermal sensitivity and tendency to degrade make stable conveying difficult. The pump was developed for applications involving rigid PVC, including recycled material streams with inhomogeneous batches. Its first practical use at Rehau Group indicates potential benefits for process stability, resource efficiency and circular economy applications in profile extrusion. Maag is presenting the development at Fakuma 2026 as a technological highlight for plastics processing.

Conveying rigid PVC without dead spaces

Rigid PVC is among the more demanding materials in extrusion because of its high thermal sensitivity and its tendency to degrade. In conventional gear pumps, polymer can remain in gaps and dead spaces for excessive periods. This may lead to deposits, material burning and process instabilities.

The extrex⁶ EC was developed to address this issue through a gap-free design without dead spaces. The design is intended to prevent polymers from adhering to or accumulating inside the pump. As a result, thermal stress on the PVC is reduced and the risk of degradation is eliminated.

Process and efficiency characteristics

The main technical features described for the extrex⁶ EC relate to stable conveying, temperature management and lower extruder load. Maag specifies the following characteristics:

• Gap-free design with no dead spaces: The configuration prevents prolonged residence times and material burning, supporting a clean process.
• Increased extruder efficiency: Uniform, pressure-stable conveying reduces the load on the extruder. Depending on the application, material throughput can be significantly increased, or energy savings of up to 20% can be achieved in the extruder while maintaining constant throughput.
• Reduction in process temperature by up to 10 °C: Optimized temperature control reduces the thermal stress on the melt. In some cases, this removes the need for expensive stabilizers.

Development and testing with Rehau

The system was developed and tested in a multi-year development partnership with Rehau Group. Intensive testing took place at Rehau’s technical center between 2022 and 2024. In early 2025, a final prototype was successfully tested with a production profile.

By optimizing the thermal balance of the pump, Maag ensured that the temperature increase through the pump did not exceed 6 °C, even when the melt temperature was already 10 °C lower. This result is relevant for rigid PVC processing, where temperature control directly affects material quality and the risk of degradation.

The Maag Group PVC pump in use at the Rehau technical center in Germany

Use with recycled PVC

The extrex⁶ EC showed particular advantages when processing cost-effective recycled PVC material with inherently inhomogeneous batches. According to the information provided, pressure fluctuations at the die were minimized by the gear pump’s constant output, which resulted in a substantial improvement in the product quality of the profiles.

At the same time, the load on the extruder decreased by up to 20%. This may contribute to a longer service life of the system and reduce costs in the maintenance cycle. In all trials with recycled material, no discoloration occurred and no additional stabilizers were required. For Rehau, this creates both an economic and environmental benefit, as expensive virgin material can be replaced with recycled material.

Implementation in production

The new PVC pump has been successfully installed for production purposes at a Rehau plant in Spain. An extended lease agreement is intended to provide the time required to gradually implement the pump system across the plastics processor’s global fleet of facilities.

Martin Schwanck, Process Engineering, Rehau Industrial Solutions SE & Co. KG, assessed the development positively: "The development of the melt pump into the current, near-production prototype was handled professionally and driven forward with great dedication by all involved. The necessary steps were coordinated in a spirit of partnership and on an equal footing. After commissioning and training at our production facility, our employees were immediately able to operate the pump independently, thanks in part to the very clear instructions. The robust design and wide process window meant that operators quickly gained confidence in the machine and came to appreciate it as an important contribution to stabilizing production."

With the extrex⁶ EC, Maag Group positions the pump as a component for improving modern extrusion processes, particularly where rigid PVC and recycled material streams require stable conveying, reduced thermal load and resource-efficient processing.