I. Precision Control of Process Workflow

The wire extrusion process follows a "melting-forming-solidification" physicochemical pathway, which can be broken down into key stages:

1. Material Preprocessing
   Polymer pellets (e.g., PVC, XLPE, TPU) undergo pre-drying at 80–120°C to eliminate moisture-induced microvoids. For advanced engineering plastics (e.g., low-smoke zero-halogen materials), moisture content must be strictly controlled to ≤0.03%.

2. Melting and Plasticizing System
   Temperature accuracy in screw extruders must reach ±1.5°C, with typical zonal gradients: feed zone (160°C) → compression zone (190°C) → metering zone (210°C). A two-stage screw design reduces melt pressure fluctuations to within ±2 MPa.

3. Die Matching Technology
   For pressure dies, the clearance tolerance between the die tip and die bushing is maintained at 0.05–0.15 mm. For fine conductors (e.g., 0.6 mm²), a compression ratio of 6:1 ensures molecular chain alignment.

4. In-Line Monitoring Systems
   Laser micrometers track diameter variations (±0.02 mm), with closed-loop feedback adjusting haul-off speeds. Infrared thermography monitors cooling trough temperature gradients to prevent crystalline defects.

II. Mathematical Modeling of Process Parameters

Extrusion quality depends on multivariate coupling, necessitating advanced control models:

• Extrusion Velocity Equation:
  $Q=\pi Dnh(1-\epsilon )\rho$
  Where $D$ = screw diameter, $n$ = RPM, $h$ = channel depth, $\epsilon$ = backflow coefficient. A 15% speed increase requires 12–18% tension adjustment.

• Heat Transfer Model:
  FEA simulations determine cooling trough length $L=0.25v(T_m-T_c)\mathrm{/}\alpha$, where $v$ = line speed, $T_m$ = melt temp, $T_c$ = coolant temp, $\alpha$ = thermal diffusivity.

• Eccentricity Control:
  CCD vision systems detect concentricity deviations, with PID algorithms adjusting die position to achieve ≥98% insulation concentricity.

III. Defect Diagnosis and Process Optimization

Root cause analysis via DOE experiments reveals solutions for common defects:

IV. Technological Evolution and Innovations

The extrusion process is undergoing intelligent transformation:

1. Digital Twin Systems
   IIoT-enabled virtual production lines predict die wear via machine learning, enabling preventive maintenance. Leading manufacturers report OEE improvements to 89%.

2. Multi-Layer Co-Extrusion
   Triple-layer systems integrate conductor shielding (semiconductive), insulation (XLPE), and sheathing (TPE) in one pass, achieving speeds up to 2,500 m/min.

3. Superconductor Processing
   Cryogenic extrusion (-250°C) for MgB₂ tapes preserves superconducting phase integrity using liquid nitrogen cooling.

4. Sustainable Manufacturing
   Bio-based polyesters (e.g., PEF) reduce carbon emissions by 62% vs. PVC. Closed-loop cooling systems cut water use by 75%.

Conclusion

From 5G communication cables to EV high-voltage wiring, wire extrusion continuously pushes material limits. With digital twins and AI-driven controls, future processes will achieve nanometer-scale precision and zero-defect production, underpinning advancements in smart grids and quantum communications. Engineers must master interdisciplinary expertise—spanning rheology, thermodynamics, and automation—to drive innovation at the intersection of materials science and Industry 4.0.