Technical Details of ZMEStructural GeometryThe base body adopts reverse threads with small lead. Multiple sets of through tooth grooves are circumferentially machined on the screw flight. The tooth profiles of the two screws intermesh to achieve mutual wiping and self-cleaning. It delivers weak reverse conveying effect; materials advance forward relying on leakage flow. The inner bore is involute spline. The tooth positions must be aligned during installation and random misalignment assembly is not allowed. Optimized root fillets reduce the risk of material adhesion and accumulation. Material Configuration• 38CrMoAlA nitrided steel: For general compounding applications. • WR5: For general high-wear compounding. • WR13: Wear and corrosion resistance, applicable to battery materials and corrosive systems. • Nickel-base alloy: Used for highly corrosive working conditions. Manufacturing ProcessIntegral forging plus heat treatment. CNC milling of tooth grooves and thread profiles. Strict control of meshing clearance with smooth transition at tooth roots. Ensure good matching of tooth profiles between twin screws to guarantee self-wiping performance. Process Parameter Characteristics• Shear level: Low‑medium shear. Shear intensity is lower than KB kneading blocks and slightly higher than SME. • Conveying capacity: Weak reverse effect. Materials move forward by leakage flow; no inherent forward pushing capability. • Shear heat: Medium, lower than KB kneading blocks and higher than SME. • Mixing type: Strong distributive mixing + moderate dispersive mixing. • Residence time: Locally prolonged with controllable residence time distribution, no stagnant dead zones. • Self-cleaning: Excellent. This is the biggest advantage compared with TME, suitable for frequent color and material changeover. | Functions of ZME•Build local backpressure and extend effective mixing time: The reverse threaded base creates backflow resistance to establish local melt backpressure and prolong material residence time, enabling sufficient mixing of additives and fillers. Materials travel forward through leakage flow and will not fully block the flow or stall the screws. •Dual mixing of distribution and moderate dispersion: Intermeshing tooth grooves repeatedly split and recombine material flow, realizing radial and axial flow exchange. It achieves uniform distribution of components and temperature, and gently breaks agglomerates of fillers and glass fiber bundles. It balances distributive and partial dispersive capacity. Its mixing performance surpasses SME while its shear intensity is milder than KB kneading blocks. •Glass fiber wetting and reduced excessive fiber breakage: ZME installed after glass fiber side feeding improves resin wetting on glass fibers and breaks fiber agglomerates. Compared with KB kneading blocks, it preserves fiber length to a greater extent and is a commonly used element for long and short glass fiber reinforced formulations. •No stagnant dead zones, suitable for color change and heat-sensitive materials: Fully intermeshed self-cleaning structure eliminates the material dead zones found in TME, reducing charred and residual materials. Ideal for heat-sensitive polymers and multi-grade frequent color change production, and cuts down machine cleaning workload. - Optimize venting and devolatilization conditions: Installed upstream of the vacuum devolatilization section, it continuously renews the specific surface area of melt and improves removal efficiency of small-molecule volatiles.
|
