Technical Details of BarrelStructural GeometryThe substrate is high‑strength forged steel, with flange and locating pin holes on end face; multiple barrel sections are assembled and locked by bolts. Common standard lengths for single section: 100 mm, 160 mm, 200 mm, 240 mm. Free combination is available to achieve different overall L/D ratios. - Closed Barrel: No window, complete housing, applied for melting section and homogenizing section.
- Open Barrel: Top / side windows machined on barrel for main feeding, side feeding and vacuum devolatilization. Vacuum hood, feeder and material baffle can be equipped.
- Liner‑type Barrel: Liner (closed liner / open liner, C‑split / monolithic liner) is interference press‑fitted into barrel cavity. Housing does not contact materials directly.
- Lineless Nitrided Barrel: Without inner liner, figure‑eight cavity is machined directly on barrel, inner wall is hardened by nitriding treatment.
Independent heating‑cooling channels are integrated inside each barrel section, every section serves as an individual temperature control zone. Precision of figure‑eight bore center‑to‑center distance is guaranteed internally to maintain screw intermeshing clearance. Material Configuration (Base Material of Barrel Housing)- 42CrMo, 45# Forged Steel: Standard housing base material, high strength, torsion‑resistant and thermal‑deformation‑resistant. Wear‑resistance and corrosion‑resistance are not required for housing itself.
- Wear‑resistant and corrosion‑resistant performance is fully realized by inner liner. Liner materials: 38CrMoAlA, WR5, WR13, Nickel‑base alloy.
Manufacturing ProcessIntegral forging and quenching‑and‑tempering heat treatment; CNC machining for flange, shoulder positioning and figure‑eight cavity; processing heating‑cooling channels and performing hydraulic pressure leakage test. Strictly control flange flatness and coaxiality to ensure concentric connection of multi‑section barrels and reduce misalignment‑caused wear. Process Parameter Characteristics- Maximum operating temperature: 350 ℃
- Melt pressure bearing: Pressure under conventional extrusion conditions
- Temperature control: Independent heating‑cooling for each barrel section, zoned temperature control
- Liner‑type barrel: Housing can be permanently reused, only inner liner needs replacement, low maintenance cost
- Lineless nitrided barrel: Good thermal conductivity, no assembly clearance; the whole barrel section shall be scrapped once inner wall is worn
- Material baffle can be installed on window of open barrel to suppress melt back‑flow and climbing.
| Functions of Barrel•Machine load‑bearing and cavity support As main housing of equipment, bear torque transmitted by screws, melt pressure and thermal stress. Accommodate complete screw assembly. Multi‑section barrel splicing realizes target overall L/D ratio and forms complete extrusion process cavity. •Sectional independent heat exchange and temperature control Each barrel section is equipped with heating‑cooling channels for precise zoned temperature control, meeting temperature requirements of conveying, melting, compounding and devolatilization respectively, and inhibiting local over‑heating degradation of materials. •Realize feeding, side‑feeding and vacuum devolatilization processes Windows of open barrel connect feeding equipment and vacuum system. Complete main feeding, side addition of glass‑fiber / powder additives, vacuum extraction of moisture, monomers and small‑molecule volatiles. Closed barrel provides sealed cavity for compression, melting and pressure building. •Protect expensive equipment body and reduce maintenance cost For liner‑type barrel, wear is transferred to liner. Materials directly contact liner instead of barrel housing suffering wear and corrosion. Damaged liner can be replaced separately without replacing whole barrel housing. •Modular flexible process combination Standard modular structure, closed barrels and open barrels can be arranged freely. Adjust feeding position, side‑feeding points and quantity of vacuum ports according to formulations, so as to flexibly change extrusion process layout. |
