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What are the differences between rubber hot-feed extruders and cold-feed extruders?
2026/11/04
Hot Feed Extruder vs Cold Feed Extruder
Key Difference
For a hot feed extruder, rubber compound is pre-warmed and plasticated on an open mill (50～70°C) before feeding. The screw only conveys, pressurizes and shapes the material. For a cold feed extruder, room-temperature rubber strips or blocks are fed directly. The screw completes plasticating, mixing, pressurizing and extrusion by itself.
表格
| Item | Hot Feed Extruder | Cold Feed Extruder |
|---|---|---|
| Feeding Condition | Pre-warming required; compound temperature 50–70°C | Room-temperature feed; no pre-warming mill needed |
| Screw L/D Ratio | Short, L/D = 4:1～6:1, deep flight channel | Long, L/D = 12:1～20:1, shallow flight channel, pin-barrel design widely used |
| Auxiliary Equipment | Must match with an open mill for preheating, manual feeding commonly | No preheating mill required; compact line, easy for automation |
| Machine Structure | Simple design, low cost, easy maintenance | Complex structure, higher installed power, higher unit price |
| Output Capacity | High output, suitable for mass production | Medium output, better dimensional stability for precision profiles |
| Dimensional Accuracy | Fair; easily affected by fluctuation of incoming compound temperature | High; stable temperature & pressure control, compatible with co-extrusion |
| Formula Compatibility | Limited, good for high-carbon-black and high-filling compounds | Wide compatibility: EPDM, silicone, colored rubber, multi-hardness compounds |
| Scorch Risk | Two heating stages (mill + extruder); higher scorch risk with poor process control | Zoned barrel temperature control; lower scorch risk |
| Typical Applications | Tire tread, large rubber blanks, coarse hoses, straining | Seals, complex profiles, cable sheathing, co-extrusion, precision rubber hoses |
Hot Feed Extruder
- The screw undertakes simple work: the rubber is already plasticated. The screw mainly pushes material, builds pressure and shapes through the die.
- Advantages: Low machine cost, large throughput. Preferred by traditional tire factories with existing milling lines.
- Disadvantages: Extra preheating process, larger floor space, more labor input; unstable dimensions due to variable feed temperature.
Cold Feed Extruder (Current Mainstream)
- Multi-function screw: conveying → shear heating & plasticating → homogenizing → pressurizing. Many models are equipped with pin barrels and venting structure.
- Advantages: Remove the preheating mill, shorter production line, fast color/formula change, stable dimension, support co-extrusion.
- Disadvantages: Higher equipment cost, sophisticated screw manufacturing, strict requirements on temperature control and processing parameters.
Quick Selection Guide
- You already have Banbury mixer + open mill preheating line, producing tire tread / large blanks, prioritizing high throughput → Hot Feed Extruder
- You produce sealing strips, complex profiles, co-extruded parts, run small batches with frequent formula changes, and want an automated compact line → Cold Feed Extruder
