ÂÌñÏ×ÆÞ

The Institute for Plastics Processing (IKV) in Industry and Craft at RWTH Aachen University (Germany) is developing an experimental method to measure the resin residence time and its local variation across the cross-section of a pultrusion profile. This research aims to enhance the understanding of flow fields in injection box technology, which is increasingly replacing traditional open impregnation baths in the production of lightweight components made of fiber-reinforced plastics (FRP). According to the institute, injection boxes improve component quality and increase process productivity, particularly with highly reactive matrix systems.

For lightweight FRP components, reinforcing fibers are continuously impregnated with a plastic matrix in processes such as pultrusion and winding. While previous research investigated geometric influences on backflow in injection boxes and derived design guidelines for the pultrusion process, it did not account for the impact of injection strategy on production speed and product quality. Additionally, the resin residence time resulting from injection box design remains unpredictable.

Featured Content

Market report: Composites and carbon fiber in hydrogen storage READ MORE

Automated Composites Knowledge Center READ MORE

Troubleshooting thermoplastic composite stamp forming READ MORE

In this study, IKV uses an impulsive change in the color of the matrix during the pultrusion process to indicate the flow field in the injection box. To analyze the flow field, the profile is cut at regular intervals, and the resulting cross-sections are examined. Each cross-section displays a distinct color distribution based on its temporal proximity to the color change. The temporal variation in color change for each cross-section component is calculated using digital image correlation, facilitating further investigation of the underlying flow fields.

The study suggests that combining insights from injection box geometry, injection strategy and the use of semi-finished textile products offers significant potential to improve impregnation quality and process efficiency.

The first project meeting on this topic will take place at IKV on Sept. 23, 2025. Registration is open, and interested parties are encouraged to contact the institute for further details.

This IGF research project (01IF23502N) of the Research Association for Plastics Processing was funded through the Industrial Collective Research (IGF) program by the Federal Ministry for Economic Affairs and Energy (BMWi), based on a resolution of the German Bundestag. The Institute acknowledges the support of all contributing institutions.

This post is courtesy of the ÂÌñÏ×ÆÞ and AZL Aachen GmbH media partnership.