2. The Ultimate PET Preform Mould Maintenance Checklist

To ensure consistent part quality and uninterrupted production, implement this tiered preventive maintenance routine in your plant:

Phase 1: Daily Maintenance Routine (Every Shift / 24 Hours)

• Parting Line & Cavity Cleaning: Wipe down parting lines, neck ring split lines, and vent grooves using lint-free cloths and approved PET solvent. Remove PET dust, flash, and oil deposits.
• Dew Point & Condensation Control: Monitor mold surface condensation during humid operations. Ensure dehumidifier units are functioning before cooling water is engaged.
• Hot Runner Nozzle Check: Visually inspect valve tips and nozzle bushings for PET degradation or drooling. Verify that temperature controllers maintain accurate thermal zoning.
• Water Leakage Inspection: Check quick-connect fittings and O-rings around the cavity plate for moisture or fluid leaks.

Phase 2: Weekly Maintenance Checklist (Every 100,000–150,000 Cycles)

• Mechanical Lubrication: Apply food-grade, high-temperature grease to guide pins, leader bushings, stroke plates, and slide mechanisms. (Avoid over-greasing near cavity openings).
• Venting System Clearing: Clean micro-vents on the core and neck rings using brass scrapers or ultrasonic baths to prevent gas traps and burn marks.
• Ejection System Verification: Test ejector plate return sensors, hydraulic/pneumatic stroke smoothness, and neck ring opening balance.

Phase 3: Monthly Preventive Maintenance (Every 500,000 Cycles)

• Cooling Channel Descaling: Flush internal core, cavity, and shell cooling circuits with a mild descaling agent to eliminate rust, lime, and calcium deposits that degrade heat transfer efficiency.
• Seal & O-ring Replacement: Inspect and replace worn silicone/viton O-rings on water manifolds and core cooling tubes.
• Valve Gate Actuation Tuning: Inspect pneumatic cylinder seals, valve needles, and piston stroke lengths for uniform gating action across all cavities.

Phase 4: Annual / Major Overhaul (Every 3,000,000–5,000,000 Cycles)

• Dimensional Metrology & Wear Analysis: Remove core pins and neck rings; measure critical dimensions, concentricity, and gate diameters using CMM equipment.
• Hot Runner System Refurbishment: Disassemble manifold blocks, inspect heater bands and thermocouples, replace worn valve tips, and deep-clean melted PET channels.
• Taper Lock & Alignment Calibration: Inspect self-locking core tapers and cavity seats. Re-grind or replace worn taper lock components to maintain zero-eccentricity preform wall thickness.