Chopped Fiber Compounding Enters Injection Molding

New CFP technology enables direct fiber compounding in injection molding, reducing costs, improving flexibility, and lowering CO₂ emissions.

A new injection molding approach now enables direct feeding of chopped fibers into the plasticizing unit, simplifying compounding and reducing processing steps. As a result, manufacturers can lower material costs, improve process efficiency, and reduce CO₂ emissions across production lines.

You can also read: Plastics Injection Molding: Definition, Benefits and Applications.

Integrating Compounding into Injection Molding

Injection molding is increasingly integrating previously separate processing steps, including part finishing and fiber compounding, into a single operation. Historically, manufacturers relied on external compounding processes to prepare fiber-reinforced materials before feeding them into injection molding machines.

Fiber-reinforced compounds remain widely used, particularly in automotive applications, to increase stiffness while maintaining the lightweight advantages of polymer materials. However, traditional production requires twin-screw extrusion, where high shear ensures proper dispersion of fibers within the polymer matrix.

Direct Fiber Feeding with CFP Technology

KraussMaffei introduces a new approach that feeds chopped fibers directly into the injection molding machine, eliminating the separate compounding step entirely. Specifically, the process uses patented screw technology to incorporate chopped fibers directly into polypropylene during plasticization within the injection unit.

The process, known as chopped fiber processing (CFP), introduces fibers at the feed throat using an additional metering system. Consequently, the screw design ensures controlled melting and homogeneous mixing without damaging the fiber structure or creating clusters.

Cost, Flexibility, and Sustainability Advantages

One of the primary advantages is cost reduction, as eliminating the compounding step significantly lowers material and operational expenses across production processes. In addition, KraussMaffei estimates a return on investment in less than one year under typical industrial operating conditions.

Flexibility also improves significantly, since processors can adjust fiber dosage and material combinations to tailor performance properties for specific applications. Furthermore, removing an additional process step reduces energy consumption, which directly lowers associated CO₂ emissions and improves overall sustainability.

Patented Screw Technology Enables Performance

The patented screw geometry enables efficient melting and mixing of the polymer matrix and fibers within a standard-length plasticizing unit configuration. Importantly, this design allows manufacturers to retrofit the technology into existing injection molding machines without requiring major equipment modifications.

According to Jörg Stech, CEO of KraussMaffei Technologies GmbH, the technology represents a significant advancement in reducing material costs. Moreover, the screw geometry serves as the core innovation, specifically engineered to support this integrated compounding process.

Redefining Mixing Capabilities in Injection Molding

This technology challenges long-standing assumptions about injection molding, where screws were traditionally considered insufficient for high-quality fiber dispersion and mixing performance. Previously, manufacturers depended on twin-screw extrusion to achieve uniform fiber distribution before processing materials in injection molding machines.

During demonstrations, engineers emphasized “gentle processing” as a key feature, ensuring fiber integrity while preventing the formation of clusters. As a result, the process minimizes fiber segregation, which remains a common issue in conventional injection molding applications.

From Standard Materials to Custom Formulations

Many processors historically relied on pre-compounded materials from suppliers, limiting flexibility and increasing dependency on minimum order quantities and external sourcing. Now, CFP technology allows manufacturers to tailor both fiber type and polymer matrix directly within the injection molding process.

This capability enables the production of customized formulations, improving part performance while offering greater control over costs and material selection. Ultimately, processors can develop in-house material expertise, strengthening their competitive position in demanding applications.

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