Some common production issues and solutions shared by a production manager who produce ESD PS Thermoforming sheet for 10years

August 21, 2025

Today I visited a client who makes single-layer thermoforming conductive PS sheets. To promote our cooperation, I had a friendly and in-depth discussion with their production manager, As an experienced extrusion operator with 10 years of expertise in this field, here are some common production issues and solutions shared by him:
Common Problems & Solutions:
1. Uneven Material Melting
Cause: Inconsistent temperature zones or material feed rates.
Solution: Calibrate temperature profiles (180-220°C for PS), ensure even dryer pre-heating (90°C for 4hrs), and check screw speed stability.
2. Conductive Filler Agglomeration
Cause: Poor dispersion of carbon black/graphite additives.
Solution: Pre-mix fillers with PS pellets in high-speed mixer (2000rpm for 5min), use twin-screw extruder for better compounding.
3. Sheet Thickness Variation
Cause: Worn die lips or inconsistent take-off speed.
Solution: Regular die polishing (chrome-plated surfaces), install laser thickness gauge with auto-adjustment system.
4. Surface Imperfections
Cause: Contaminated melt or improper cooling.
Solution: Install melt filter (40μm mesh), maintain water bath temperature (15-20°C), and check air knife alignment.
5. Die Build-Up
Cause: Degraded polymer sticking to die surfaces.
Solution: Implement automatic die cleaning system, use PTFE-coated dies, and schedule daily purging with HDPE.
6. Electrical Conductivity Fluctuations
Cause: Inconsistent filler concentration.
Solution: Install gravimetric feeder (±0.5% accuracy), perform inline resistivity testing (4-point probe method).
7. Melt Fracture
Cause: High shear stress at die exit.
Solution: Increase die land length, reduce output rate (maintain <50kg/hr), or add processing aid (0.2% fluoropolymer).
8. Preventive Maintenance Routine:
Daily: Die inspection, filter replacement, and thickness calibration
Weekly: Screw/barrel wear check, temperature controller validation
Monthly: Motor alignment verification, cooling system descaling
Experienced operators develop "touch diagnostics" - feeling barrel heat distribution and listening to motor sound variations to preempt issues before quality deviations occur.