Plastic Extrusion‑Pelletizing Equipment
Plastic Extrusion‑Pelletizing Equipment
Multiple domestic factories for bidding. Free promotion. Price to be negotiated between winning bidder and buyer.
Please provide below information for posting:
- New or used; 2. Machine model or screw diameter; 3. Screw quantity: single‑screw, twin‑screw, triple‑screw; 4. Screw rotation direction; 5. Screw L/D ratio; 6. Screw type; 7. Motor power; 8. Brand scope requirement; 9. Purchase quantity
表格
| Type | Working Principle | Core Advantages | Main Limitations | Typical Applications |
|---|---|---|---|---|
| Single‑Screw Extruder | Material conveying, melting and metering take place between one single screw and barrel by friction and viscous drag. | Mature design, low cost, wide‑spread application, cost‑effective and easy maintenance. | Moderate mixing performance, poor self‑cleaning; less suitable for complex formulations such as high‑fill and polymer blending. | General plastic products: pipes, profiles, sheets, film blowing, wire & cable sheathing. |
| Twin‑Screw Extruder | Two intermeshing screws rotate; positive‑displacement dominated conveying. | Outstanding mixing performance, uniform shear, good self‑cleaning, high throughput; ideal for intensive compounding. | Sophisticated structure, high manufacturing cost, higher operation & maintenance requirements. | Polymer modification (blending, reinforcement, filling), color masterbatch pelletizing, high‑viscosity or heat‑sensitive material processing. |
| Multi‑Screw Extruder | Three or more screws with complex mechanical layout; theoretically superior output and mixing performance. | High throughput and excellent dispersion; advantages for ultra‑high‑viscosity and ultra‑dispersion special‑grade applications. | Extremely complicated structure, high capital cost, relatively narrow application scope. | Special‑purpose materials and high‑end demanding niche fields. |
Tapered twin‑screw extruder: screw diameter gradually decreases from feeding zone to metering zone. Specially optimized for direct processing of PVC powder. Features positive extrusion, good plasticization and low shear heat to avoid polymer degradation.
Key distinction for twin‑screw: co‑rotating vs counter‑rotating
表格
| Type | Rotation Mode | Core Features | Main Applications |
|---|---|---|---|
| Co‑Rotating Twin‑Screw | Both screws rotate in identical direction. | High‑speed & high‑torque; powerful dispersive & distributive mixing; excellent self‑cleaning property. | Compounding & pelletizing: plastic modification, masterbatch production, polymer alloys. |
| Counter‑Rotating Twin‑Screw | Two screws rotate in opposite directions (mostly outward). | Positive‑displacement conveying, strong pressure‑building capacity, stable extrusion, relatively weaker mixing capacity. | Direct forming of PVC pipes, profiles and sheets. |
Core Technical Specifications: Key Selection Indicators
Screw Diameter (mm): Primary dimension defining machine size and throughput. Lab scale: 12 mm, 20 mm, 25 mm; industrial grades: 45 mm, 60 mm, 75 mm, up to 120 mm and above. Larger diameter generally delivers higher hourly output.
L/D Ratio (Length‑to‑Diameter): Ratio of effective screw working length to diameter, governing plasticizing and mixing intensity. Longer L/D extends material residence time inside barrel. ‑ General extrusion: 20:1‑30:1 ‑ Modification & pelletizing: 30:1‑40:1, even 42:1 / 44:1 for demanding recipes ‑ Venting‑type extruders normally adopt larger L/D to satisfy degassing requirements.
Screw Rotational Speed (r/min): Influences throughput and shear intensity. Higher speed brings higher output and stronger shear, yet imposes higher requirements on material and hardware. ‑ Conventional single‑screw: 0‑80 r/min or 30‑300 r/min ‑ High‑performance twin‑screw: 500‑600 r/min; some advanced models exceed 1800 r/min.
Motor Power (kW): Driving capacity for screw rotation. Higher power permits processing higher‑viscosity materials and supports larger throughput.
Throughput (kg/h): Final productivity indicator, closely correlated with screw diameter, rotating speed and material properties. Large single‑screw machines can reach 600‑2500 kg/h.
Selection Guidelines
Follow clear logic for extrusion‑pelletizing equipment selection:
Determine machine type by process purpose ‑ General‑purpose plastic articles (pipe, profile, film): single‑screw extruder offers cost‑effective solution. ‑ Compounding pelletizing, plastic modification, color masterbatch: co‑rotating twin‑screw extruder is mandatory. ‑ Direct forming from PVC powder: tapered twin‑screw extruder is the professional option.
Select screw diameter according to target output: Match screw diameter referring to typical throughput range for expected production volume.
Set L/D ratio according to formulation complexity: More complex recipes with numerous additives require higher L/D for sufficient mixing.
Pay attention to auxiliary‑line matching: The extruder serves as main unit; complete production requires well‑matched downstream auxiliaries such as cooling water tank, puller and pelletizer.
Participation Process
Manufacturers: Contact supplier service for supply registration.
Buyers: Click group‑purchase or contact procurement service to submit requirements. The platform filters suppliers from database or releases bidding based on aggregated demands. Buyers select competitive suppliers and sign sales contracts.
