Technical Details of LinerStructural GeometryThe inner bore adopts figure‑eight intermeshing flow channel for twin‑screw, the center‑to‑center distance of twin bores is strictly controlled to maintain reasonable clearance with screw elements. - Closed Liner: Fully enclosed figure‑eight inner bore without window, applied for general melting and homogenizing barrels.
- Open Liner: Through‑type window opened on upper part, matching feeding, venting and side‑feeding windows of barrel.
- C‑split Liner: Split into two halves for assembly and disassembly convenience; minor material accumulation risk exists at splicing gap.
- Monolithic Liner: Integrally formed figure‑eight bore with no splicing gap, fewer dead zones for material retention, yet higher machining difficulty and cost.
Outer circle adopts interference fit with barrel housing. Axial shoulder positioning is arranged to prevent axial shifting and circumferential rotation during operation. Material Configuration- 38CrMoAlA Nitriding Steel: For general modification conditions, cost‑effective, treated by nitriding hardening.
- WR5 Powder Alloy: High wear resistance, for glass‑fiber filled and ordinary high‑fill modification.
- WR13 Powder Alloy: Wear‑resistant & corrosion‑resistant, for battery slurry and corrosive material systems.
- Nickel‑base / Hastelloy Alloy: Severe corrosion conditions, fluoroplastics and reactive extrusion.
Manufacturing ProcessIntegrally forged blank with quenching‑and‑tempering heat treatment; CNC precision machining for figure‑eight inner bore; smooth fillet transition for window of open liner; inner wall nitriding or powder metallurgy HIP hot isostatic pressing to form hard alloy layer. Strictly control inner bore dimension and center‑to‑center distance to guarantee reasonable unilateral clearance between screw and liner, so as to achieve self‑cleaning performance. Process Parameter Characteristics- Max operating temperature: 350 ℃
- Assembly: Interference press‑fit with barrel housing
- Unilateral working clearance: 0.2‑0.4 mm (varies according to machine size)
- C‑split type: Easy disassembly & assembly, low cost; slight risk of material accumulation at splicing gap
- Monolithic liner: Gap‑free, anti‑material‑accumulation, suitable for frequent color‑change and heat‑sensitive materials
- Thermal conduction: Outer wall fits barrel inner wall, heat transfers to heating‑cooling channels of barrel.
| Functions of Liner•Wear & corrosion resistance, protect barrel housing Directly bear material friction and chemical corrosion from melt. All wear loss concentrates on liner. Only replace liner after wear, expensive barrel housing can be reused for long‑term service, reducing spare‑part cost of whole machine. •Form figure‑eight process flow channel Provide figure‑eight working cavity for screw rotation, ensure intermeshing operation of twin screws, control clearance between screw and inner wall, satisfy process requirements of material conveying, pressure building, melting and compounding. •Distinguish process windows to match different barrels ‑ Closed liner: Fully enclosed flow channel, used for closed barrels in melting and homogenizing sections. ‑ Open liner: Reserved window to realize main feeding, side feeding, vacuum devolatilization and venting. •Reduce material retention, optimize production stability Monolithic liner has no splicing gap, optimized window fillet reduces hanging material and burnt material. Suitable for heat‑sensitive materials and frequent color‑change production. C‑split liner applies to general modification scenarios with cost priority. •Realize heat exchange Outer wall of liner closely fits barrel, transfers heat to heating‑cooling channels of barrel, and realizes precise sectional temperature control for materials. |
