Advanced Die-Face Pelletizing for Continuous Polymer Production

The EXTRUTEX Water-Ring Die-Face Pelletizing Machine combines melt extrusion, die-face cutting and rapid water cooling in one compact process section. Molten polymer is delivered through a precision die plate and is cut directly at the die face by a rotating cutter. A controlled water ring immediately surrounds the cutting area and removes heat from the newly formed pellets.

This arrangement eliminates the long strand-cooling path used by conventional strand pelletizing. Instead of extruding strands, pulling them through a water bath and then feeding them into a separate cutter, the material is transformed into pellets directly at the die. The result is a compact and highly integrated pelletizing process that can be adapted to a wide range of polymer formulations.

The system is particularly valuable where production speed, thermal control and consistent pellet geometry are important. By controlling melt temperature, die pressure, cutter speed, water temperature and water circulation, the process can be tuned to the rheological behavior of the polymer. EXTRUTEX can engineer the complete line around the customer's material, required capacity, pellet size and downstream handling requirements.

Operating Principle

Prepared polymer enters the feeding system and is conveyed into the selected extrusion unit. The melt is progressively heated and homogenized while pressure is developed ahead of the die. Where the formulation requires intensive dispersion, the upstream machine can be equipped with an appropriate screw configuration, feeding system and mixing section. For gentler materials, the process can be designed around lower shear and controlled temperature development.

After filtration and pressure stabilization, the homogeneous melt enters the die plate. Multiple die holes create a continuous melt output across the die face. A rotating cutter positioned immediately in front of the die divides the melt into individual pellets. The cutter and die geometry are selected according to material viscosity, output and desired pellet characteristics.

Water is circulated around the cutter and die-face area. The newly cut pellets are cooled rapidly and carried away from the cutting zone with the circulating water. The mixture then enters the separation and drying section, where water is removed and the finished pellets are prepared for conveying, packaging or further processing.

Key Engineering Benefits

Material and Application Range

The EXTRUTEX system can be designed for virgin polymers, recycled feedstock and formulated compounds. The correct upstream extrusion technology is selected according to melt viscosity, filler loading, thermal sensitivity, dispersion requirements and production target.

Reinforced PE and EVA Compounds

PE, EVA and related formulations containing calcium carbonate, talc, titanium dioxide, carbon black and other additives can be processed when the feeding and mixing system is matched to the formulation. Intensive mixing may be provided by a co-rotating twin-screw extruder, while more temperature-sensitive materials can be considered for a co-kneader configuration.

PPR and PE-X Pipe Compounds

The pelletizing line is suitable for compound production used in PPR and PE-X pipe applications. Stable melt temperature and reliable filtration are important because formulation consistency directly affects the quality of the final pipe. EXTRUTEX can integrate dosing, extrusion, filtration and pelletizing into one production line.

TPR, TPU and EVA Flexible Compounds

Flexible thermoplastics can require careful thermal management. The water-ring system provides rapid cooling directly after cutting, while the upstream extrusion section can be designed for the required shear level and residence time.

Masterbatch Production

PE, PP, ABS, PS and EVA carrier systems can be processed for color and additive masterbatch production. For high pigment concentration or demanding dispersion, a co-rotating twin-screw extruder can provide the required mixing intensity before the melt reaches the die-face pelletizer.

Functional Masterbatch

Functional compounds based on ABS, PE, PP and EVA may contain additives that require accurate dosing and dispersion. EXTRUTEX can integrate gravimetric feeding and a modular twin-screw configuration where the formulation requires stronger mixing control.

Recycling and Prepared Feedstock Applications

Single-Stage Agglomeration Pelletizing Machine

The following EXTRUTEX configurations represent the supplied single-stage capacity range. The values are engineering reference figures; actual output depends on polymer grade, bulk density, formulation, moisture, filler percentage, feed preparation and operating conditions.

Double-Stage Agglomeration Pelletizing Machine

For more demanding feedstocks, EXTRUTEX can supply a two-stage arrangement. Separating the main melting and processing stage from the final melt-conditioning stage can improve process flexibility, particularly when recycled material, variable feedstock or demanding formulations require additional control before die-face pelletizing.

Single-Screw, Co-Kneader or Co-Rotating Twin-Screw?

A major advantage of the EXTRUTEX platform is that the pelletizing section can be matched to different extrusion technologies. The customer does not need to use a single-screw machine for every application. EXTRUTEX engineers can select the upstream machine according to the formulation and required processing behavior.

Single-Screw Extruder

A single-screw extruder is a practical choice when the primary requirements are stable feeding, melting, conveying and pressure generation. It is particularly suitable for many recycled polymer streams and formulations that do not require intensive dispersive mixing.

Co-Kneader

An EXTRUTEX co-kneader can be selected when gentle processing and controlled temperature development are important. The combination of reciprocating screw movement and rotary shear provides an alternative processing route for heat-sensitive compounds and materials where excessive shear should be minimized.

Co-Rotating Twin-Screw Extruder

An EXTRUTEX co-rotating twin-screw extruder is the preferred architecture for many demanding compounding operations. Modular screw elements allow the process to be configured for conveying, melting, distributive mixing, dispersive mixing, devolatilization and pressure build-up. This makes it especially useful for filled compounds, masterbatch and functional formulations.

Pellet Quality and Process Control

Consistent pellet quality is determined by the complete process rather than the cutter alone. Melt temperature, die pressure, polymer viscosity, die-hole diameter, cutter speed, cutter condition, water temperature, water flow and residence time all influence pellet geometry and cooling behavior.

EXTRUTEX therefore approaches the pelletizer as part of a complete process line. For a new project, the engineering team can evaluate the polymer grade, MFI or viscosity, filler and pigment loading, moisture, contamination level, feedstock form, target capacity and desired pellet dimensions. These parameters are used to determine the appropriate extrusion system, screw configuration, die design, cutter arrangement and water-handling equipment.

Line Configuration and Automation

A complete EXTRUTEX pelletizing line may include material feeding, dosing, agglomeration, extrusion, melt filtration, pressure measurement, die head, die-face cutter, water circulation, pellet separation, drying, conveying and finished-pellet collection. Depending on the application, gravimetric feeders and automated process controls can be incorporated.

Temperature zones, melt pressure, motor load, extrusion speed, cutter speed and water conditions can be monitored from the central control system. The objective is simple: maintain a stable operating window so that changes in feed rate or material behavior do not immediately translate into unstable pellet size or excessive process variation.

EXTRUTEX Engineering and Manufacturing

EXTRUTEX equipment follows an Austrian design approach focused on practical engineering, maintainability and industrial reliability. Manufacturing is carried out in China, including production facilities in Nanjing and Shanghai. This combination gives customers access to European-oriented engineering development together with modern Chinese manufacturing capacity.

EXTRUTEX can supply individual machines or complete processing lines. The engineering scope can be adapted from a basic pelletizing unit to a fully integrated compounding and recycling system with automatic feeding, filtration, pelletizing, drying and conveying.

Technical Advantages

• Direct rotary cutting at the die face.
• Immediate water cooling of freshly formed pellets.
• Compact pelletizing layout.
• Continuous industrial operation.
• Suitable for medium- and high-throughput production.
• Adaptable to recycled and virgin polymer feedstocks.
• Applicable to LDPE, LLDPE, PE, PP, EVA, ABS, PS, TPU, TPR and related formulations.
• Suitable for reinforced compounds, pipe compounds and masterbatch.
• Single-stage and double-stage configurations.
• Compatible with single-screw extrusion.
• Can be configured with an EXTRUTEX co-kneader.
• Can be configured with an EXTRUTEX co-rotating twin-screw extruder.
• Engineering can be matched to filler loading, viscosity, thermal sensitivity and production target.

EXTRUTEX Water-Ring Die-Face Pelletizing Solution

The EXTRUTEX Water-Ring Die-Face Pelletizing Machine is designed as a flexible production platform rather than a one-material machine. Whether the project involves recycled LDPE film, LLDPE film, PP raffia, woven bags, PE or PP rigid flakes, squeezed film, filled compounds, pipe compounds, flexible thermoplastics or masterbatch, the process can be configured around the material.

For straightforward melting and conveying, the system can use a single-screw extruder. Where low-shear processing and thermal control are more important, an EXTRUTEX co-kneader can be selected. Where intensive mixing, filler dispersion or demanding masterbatch production is required, the line can be built around an EXTRUTEX co-rotating twin-screw extruder. The water-ring die-face section then provides the final direct cutting and rapid cooling stage.

EXTRUTEX — Austrian design, manufacturing in Nanjing and Shanghai, China, and complete polymer processing solutions engineered around the material and the production target.