90/24 Parallel Twin Screw Barrel

Product Overview

The 90/24 parallel twin screw barrel is a specialized extruder component designed for large-scale plastic processing. Key aspects include:

• Twin Screw Configuration: Compatible with co-rotating twin screw extruders featuring two screws with a diameter of 90 mm (L/D = 24, 2160 mm length) for continuous polymer transport.
• High Efficiency: Parallel geometry allows for high production rates (tons/hour) with homogeneous melting by maintaining a constant free volume.
• Comprehensive Polymer Mixing: Co-rotating screws provide exceptional distributive and dispersive mixing, ensuring complete incorporation of additives (fillers, plasticizers, colorants) into the melt.
• Durable Construction: Typically machined from high-alloy steel (e.g., 38CrMoAl) and hardened on the surface; designed for tight tolerances and long wear life.
• Industrial Use: Commonly used in extruder systems for PVC pipe/profile, WPC flooring, sheet/film, and general compounding that require stable melt flow and high efficiency.

🛠️ Technical Specifications Table

Design Features and Advantages

The 90/24 barrel design offers various advantages in operation:

• Superior Mixing: As a co-rotating parallel extruder, it ensures excellent distributive and dispersive mixing of polymers and additives, resulting in a homogeneous melt.
• High Output Efficiency: Constant screw diameter provides maximum efficiency and balanced shear force throughout the barrel. This feature supports high-volume production with stable torque.
• Wear Resistance: Screws/barrel made from nitrided alloy steel (and optionally coated) show resistance to wear from fillers or reinforced compounds, significantly extending service life.
• Narrow Gap (Tolerances): Precision machining provides minimum screw-barrel gaps that maintain melt pressure and minimize melt slippage. Consistent gaps prevent fluctuations or pressure drops.
• Homogeneous Processing: Multiple barrel zones (feeding, compression, metering) and intermeshing flights ensure uniform melting, comprehensive venting (if applicable), and smooth extrudate (core product) formation. Stable temperature control (multiple heating/cooling zones) supports consistent output quality.

Production and Quality Control

The 90/24 barrel is produced through rigorous processes to ensure reliability:

• Material Preparation: Begins with forged alloy steel billets (38CrMoAl or similar) for strength and toughness.
• CNC Machining: Screws and barrel are precisely turned and milled according to profile (flights, deep drilling, keyways) using CNC equipment. Machining accuracy ensures concentricity and correct flight (pitch).
• Heat Treatment: After rough machining, parts are quenched and tempered to achieve specified core hardness (~HB280–320). Nitriding is then applied for surface hardening (~850–1000 HV).
• Surface Treatment: After nitriding, surfaces are ground and polished to final finish value (≤0.4 µm Ra). Optional coatings (nickel, chrome) can be added for enhanced wear protection.
• Inspection and Testing: Each component undergoes dimensional inspection (diameter, linearity max. 0.015 mm), hardness testing, and run-out measurement. Screw/barrel matching is verified for correct gap. Quality is assured according to international standards (ISO 9001 or equivalent).
• Documentation: Material certificates, heat treatment records, and hardness reports are provided. Each barrel is traceable by serial number for quality assurance.

Compatibility and Applications

The 90/24 twin screw barrel is compatible with industrial extruders and various polymers:

• Extruder Types: Suitable for 90 mm class parallel (co-rotating) twin screw extruders. Mounted on standard gearbox flanges; customizable for non-standard machines.
• Polymer Materials: Highly suitable for PVC (rigid and plasticized), PP/PE, WPC (wood-plastic composites), ABS, and other thermoplastics requiring dense compounding. Can process filled, foamed, or high-viscosity formulations.
• Industries: Widely used in PVC pipe/profile extrusion, sheet and film lines, cable and pipe jacketing, and WPC flooring production. Also utilized in large-scale compounding facilities for masterbatch or additive mixing.
• Efficiency Ranges: Designed for medium to large production lines requiring continuous, stable extrusion (e.g., from several hundred to 1000+ kg/hour depending on polymer and extruder).
• Accessory Integration: Compatible with downstream equipment such as vacuum holes, cooling calibration tanks, and take-off cutters. Works as part of complete extrusion systems for construction materials, packaging, and composite sheets.

Installation and Maintenance

Proper installation and maintenance ensure optimal performance:

• Alignment: Carefully align screws during assembly. Ensure correct end gap and alignment with drive coupling according to extruder guide. Tighten flange bolts to specified torque.
• Pre-Operation Checks: Verify screw-barrel gap (according to manufacturer specifications, typically 0.05–0.1 mm). Apply a thin layer of high-temperature grease or oil to screw flights to reduce initial wear.
• Cleaning: Drain the extruder and clean the barrel after each operation. Use appropriate solvents or cleaning (pigging) methods to remove polymer residues. Avoid abrasive tools that could scratch nitrided surfaces.
• Lubrication: If storing or leaving idle, coat screws and internal bore with anti-corrosion oil. Remove all oxidation before reassembly.
• Wear Monitoring: Periodically measure outer diameters and flight depths. Inspect for scratches or wear. Plan for re-nitriding or replacement if wear exceeds ~0.5 mm.
• Safety: Use lifting equipment for transport (barrels are heavy). Protect nitrided surfaces from impact or moisture. Follow lockout/tagout procedures before disassembly and use appropriate personal protective equipment (PPE) while handling.

Customization Options

The 90/24 design can be tailored to specific production needs:

• Screw Configuration: Modify flight geometry, pitch, compression ratio, and mixing block arrangements based on material (e.g., more mixing elements for filled compounds).
• Alternative Materials: Use different steels (34CrAlNi7, 42CrMo, SKD61/H13, 17-4PH, etc.) or stainless alloys for special applications (e.g., corrosive materials). Optionally apply a bimetallic liner or Xaloy coating to screw surfaces for extreme wear.
• Surface Coatings: Add chrome, ceramic, or polymer coatings (e.g., PTFE) to reduce wear or sticking.
• Size Variations: Change length (e.g., 90/22 or 90/28) or screw diameter for different extruder models or efficiency requirements.
• Mounting and Accessories: Provide custom flange patterns, fully hardened barrels for enhanced corrosion resistance, or integrated flanged adapters. Add feeding ports, gas venting holes, or segmented (bolted together) screws for flexibility. All configurations are custom-designed according to the customer's polymer formulation and capacity.

Safety and Handling

Basic precautions when working with heavy extruder components:

• Personal Protection: Always wear gloves, safety glasses, and steel-toed boots. Hardened edges can cut or break.
• Heavy Lifting: Use cranes, hoists, or forklifts to move screw/barrel assemblies. Do not drag on the ground. Secure loads during lifting to prevent drops.
• Temperature: Barrels remain hot after operation. Wait for them to cool before handling or use heat-resistant gloves.
• Storage: Store barrels horizontally or on support skids to prevent bending. Keep in a dry area; cover with anti-corrosion agents if not in use.
• Installation Safety: Ensure machine power is locked out and safety locks are engaged during maintenance. Check that all safety guards (feed hoppers, covers) are in place before starting.
• Alignment Considerations: Keep hands clear of pinch points during trial runs. Verify balanced operation at low speed before transitioning to full production.