Technical Details of Single‑Start ElementStructural Geometry• Single helical screw flight with wide flight width. Under the same outer diameter, the single‑start screw channel is deeper and delivers high free volume for solid materials. • Two structural types: ① Fully intermeshed self‑cleaning single‑start element: Threads of twin screws intermesh and wipe each other with complete self‑cleaning performance. Wide screw flight brings low leakage flow and allows short‑time contact with melt. ② SSK (SFV) scooped single‑start type (non‑fully self‑cleaning): Scooped curved screw flight for further enlarged volume. Non‑complete meshing without mutual wiping, poor self‑cleaning. It is only used in solid conveying section; carbonized material buildup easily occurs when exposed to melt. • The inner bore adopts involute spline to withstand high torque. Material Configuration• 38CrMoAlA nitrided steel: Ordinary pellets and general powder materials. • WR5: High‑wear mineral filling conditions. • WR13: Wear and corrosion resistance for battery powder. • Nickel‑base alloy: For highly corrosive working conditions. Manufacturing Process• Integral forging and quenching & tempering heat treatment. • CNC milling of single‑start helical profile. • Large fillet at thread root to reduce material adhesion. • Strictly control outer diameter and torque bearing capacity of spline. Process Parameter Characteristics• Shear level: Almost no shear • Conveying capacity: Extremely strong solid conveying performance • Shear heat: Extremely low, nearly no shear temperature rise • Mixing type: Barely any mixing, only for conveying • Torque: Under identical working conditions, it can bear higher torque than twin‑start elements | Functions of Single‑Start Element•Enhance feeding capacity for low bulk density materials: Wide and deep screw channels capture fluffy powder, fiber and foamed recycled materials, eliminate feeding bridging and slipping, break feeding bottlenecks and raise the upper limit of machine throughput. It is arranged in the main feeding section and after side feeding. • Low-temperature pushing of solids to avoid pre-melting slipping: Almost no shear input, no shear heat generated during solid conveying. Prevent premature melting of powder and adhesion on screw channels to ensure stable feeding. • Reduce melt leakage flow (fully intermeshed single‑start type): Wide screw flight provides good sealing effect. It can be applied in metering extrusion section to reduce melt backflow and leakage, and deliver certain pressure‑building capacity. |
