Technical Details of Opening CylinderStructural Geometry• The base body is a high‑strength forged steel housing with a figure‑eight (∞) inner cavity. Large windows are machined on the top or side of the barrel. Window flanges are used for connecting feeders, vacuum hoods and side‑feeders. End‑face flanges are equipped with locating pin holes for bolt‑fastened assembly of multiple barrel sections. Independent heating‑cooling flow channels are arranged inside the barrel to realize segmented temperature control. • Liner‑equipped type: An open‑type liner (C‑type split liner / monolithic open‑type liner) is fitted inside the barrel cavity with interference fit. The liner forms the figure‑eight working flow channel, while the housing only bears loads and does not come into direct contact with materials. • Liner‑free monolithic nitrided barrel: No inner liner; the figure‑eight bore is machined directly on the barrel body with nitrided hardened inner wall. • Material‑stop blocks can be fitted to the windows to restrain melt back‑flow and upward migration into vent ports. Material Configuration• 42CrMo, 45# forged steel: Standard base material for barrel housing, featuring high strength and resistance to torsion and deformation. • Wear‑resistant and corrosion‑resistant performance is achieved by the inner open‑type liner; the housing generally does not contact abrasive materials directly. • Optional inner liner materials: 38CrMoAlA nitrided steel, WR5 powder alloy, WR13 powder alloy, nickel‑base alloy. Manufacturing Process• Integral forging followed by quenching‑and‑tempering heat treatment. • CNC machining of figure‑eight cavity, window flanges and end‑face locating shoulders. • Internal cooling/heating channels are machined inside the barrel with hydraulic leakage test. • Flatness of flange faces and center‑to‑center distance are strictly controlled to guarantee coaxiality for joint assembly of multiple barrel sections. Process Parameter Characteristics• Maximum operating temperature: 350 °C • Pressure resistance: Compatible with normal melt pressure of extruders • Temperature‑control mode: Independent water/oil heating‑cooling circulation for each barrel section • Liner‑equipped structure: Housing can be reused permanently; only inner liners need replacement after wear, resulting in low maintenance cost. • Liner‑free nitrided barrel: Good thermal conductivity without assembly gaps; the whole barrel section will be scrapped once inner wall is worn. • Window configuration: Capable of mounting material‑stop blocks, vacuum hoods, feeding hoppers and side‑feeder interfaces. | Functions of Opening Cylinder•Equipment load‑bearing and cavity support: As the main housing of the machine, it withstands screw torque, melt pressure and thermal stress. It accommodates screw assemblies and connects with adjacent barrel flanges to build the overall L/D ratio of the extruder. The internal flow channel cooperates with screw elements to complete material conveying and mixing processes. •Realize material feeding and side‑feeding: Top‑open barrel is used for main feeding of pellets and powders into the screw flow channel. Side‑open barrel connects with side‑feeders to add glass fiber, powder and additives downstream of the melting section, preventing premature high‑temperature degradation of heat‑sensitive fillers. •Vacuum devolatilization and atmospheric venting: Vacuum‑open barrel connects to vacuum system to remove moisture, monomers, solvents and low‑molecular volatiles from melt. Atmospheric‑open barrel discharges entrained air, improves powder feeding and eliminates bubble defects in pellets. Material‑stop blocks can be installed on windows to prevent melt back‑flow into vacuum pipelines. •Segmented independent temperature‑control heat exchange: Internal flow channels of barrel housing provide heating and cooling for precise temperature control of materials in this barrel section, suppressing local over‑heating and degradation. •Modular flexible combination: Standard block‑type structure, freely combinable with closed‑type barrels. Feeding positions, vent quantity and side‑feeding positions can be adjusted according to formula and process requirements to flexibly configure extrusion process layout. |
