Technical Details of Single Key ConnectionStructural Geometry• Shaft: Cylindrical base with one long axial keyway milled on surface. • Inner bore of screw element: Smooth cylindrical hole with matching internal keyway. • Flat key is fitted between keyways of shaft and element. Torque is transmitted by compression on both side faces of the key. • Axial positioning and locking of elements are realized via retaining rings and lock nuts. Material Configuration• Screw element body: 38CrMoAlA, WR5, WR13 • Flat key: 45#, 40Cr quenched & tempered alloy steel Manufacturing Process• Turning of shaft outer diameter and milling of shaft keyway. • Machining of cylindrical inner bore and internal keyway on screw elements. • Grinding and matching fabrication for flat key. • Simple manufacturing process with low production cost. Process Parameter Characteristics• Torque capacity: Low-medium torque, not suitable for high specific torque main extruders. The keyway weakens the cross-sectional strength of shaft. Key crushing, shear fracture and plastic deformation of keyway tend to occur under high torque conditions. • Centering accuracy: Moderate. Circumferential clearance appears after repeated disassembly and assembly, leading to phase offset of elements. • Interchangeability: Poor. Strong pairing dependency between element and shaft, low compatibility across different machines. • Assembly & disassembly: Simple operation. • Typical failure modes: Flat key crushing, key shear fracture, rolling deformation of shaft keyway. | Functions of Single Key Connection•Transmit rotational torque. Transfer rotary power from core shaft to each screw element, driving conveying, kneading and mixing elements to rotate synchronously for material conveying and compounding. •Enable modular axial assembly. Screw elements can slide axially along the core shaft. The sequence of screw configuration can be freely adjusted to meet process modification requirements. | 
