Troubleshooting Step

Potential Cause

Technical Analysis & Solution

1. Screw Inspection​

Screw bending or deformation.

Detection: Measure runout on a platform with a dial indicator (<0.05mm/m tolerance).
Solution: Minor bends can be straightened; severe deformation requires replacement.

2. Material & Process Match​

Mismatch between resin viscosity and screw design (e.g., shallow flight).

Detection: Record torque/pressure data.
Solution: Increase melt temp or upgrade to a better-matched screw (higher compression ratio).

3. Support System Check​

Worn/damaged thrust bearing at screw tail.

Detection: Run idle (no heat/no material) and listen for tail noise.
Solution: Replace bearings and check lubrication.

4. Barrel Wear/Deform​

Uneven barrel wear altering radial clearance.

Detection: Use an internal bore gauge.
Solution: Re-bore barrel or replace.

Troubleshooting Step

Potential Cause

Technical Analysis & Solution

1. Sensing System​

Damaged or loose thermocouple.

Detection: Check resistance or compare to a known temp source.
Solution: Replace sensor; ensure tight contact with barrel.

2. Heating System​

Failed heater bands or poor contact.

Detection: Use a clamp meter to check current.
Solution: Replace bands; use thermal paste for contact.

3. Cooling System​

Leaking/cracked cooling lines causing overcooling.

Detection: Check for constant water flow/leaks.
Solution: Repair valves; ensure automatic control.

4. Control Loop​

PID parameters require tuning.

Detection: Observe oscillating temperature curves.
Solution: Re-tune PID or replace SSR/Thermocouple module.

Troubleshooting Step

Potential Cause

Technical Analysis & Solution

1. Shutdown Management​

Wet plant air entering the barrel during shutdown.

Solution: Establish SOP: Purge with clean PE/PP, close hopper gates, blow out with dry air.

2. Cooling Water Mgmt​

Coolant temp too low, causing dew point condensation.

Detection: Touch throat; feel for excessive cold/wetness.
Solution: Adjust water temp to 20-30°C (ambient).

3. Material Drying​

Hygroscopic material (PA/PET/PC) not dried properly.

Detection: Check dew point and drying time.
Solution: Strictly enforce drying specs.

Problem Category

Potential Cause

Technical Analysis & Solution

Foreign Object​

Dust, worn metal debris, or operator contamination.

Systematic Cleaning: Implement 5S standards. Install high-quality screen packs. Clean hoppers/grinders regularly.

Raw Material​

Degradation (carbonization) or poor flow properties.

Lifecycle Management: Incoming inspection -> Sealed Storage -> FIFO -> Thorough Purging.

Troubleshooting Step

Common Mistake

Consequence & Solution

1. Seals​

Forgetting to install gaskets/washers.

Consequence: High-pressure leakage.
Solution: Use assembly checklists; include full seal kits.

2. Fastening​

Incorrect torque sequence or reusing stretched bolts.

Consequence: Vibration-induced failure.
Solution: Use torque wrenches; define bolt specs.

3. Cleaning​

Residual old material on mating faces.

Consequence: Leakage or poor heat transfer.
Solution: Mandatory cleaning step before assembly.

4. Alignment/Gap​

Forcing screw installation; ignoring thermal expansion.

Consequence: Screw bending or seizure.
Solution: Train staff on proper fit; follow manual gaps.