Applicable Systems
Haitian Injection Molding Machine
Symptoms
The Haitian injection molding machine displays alarm HT002, indicating holding pressure anomaly. The holding or packing pressure is not being maintained at the setpoint, causing dimensional instability in the molded parts.
Possible Causes
- Check ring is worn or stuck, allowing backflow of melt past the screw tip during the holding phase
- Pressure sensor has drifted or the transducer mounting is loose, causing inaccurate pressure feedback
- Non-return valve is leaking, causing the holding pressure to decay rapidly after injection
Troubleshooting Steps
- Step 1: Inspect the check ring and non-return valve for wear, scoring, or damage
Check ring and non-return valve seal tightly with no visible wear or scoring on the mating surfaces - Step 2: Calibrate the pressure sensor with a reference gauge
Sensor reading matches the reference gauge within 2 percent across the full pressure range - Step 3: Monitor the holding pressure decay curve after the injection-to-hold transition
Pressure holds steady during the holding phase with less than 5 percent decay over the hold time
How to Reset
To reset: 1) Replace the worn check ring or non-return valve. 2) Replace or recalibrate the pressure sensor. 3) Press RESET. 4) Verify holding pressure is stable during a test shot.
Source: Haitian Injection Molding Machine Manual, Haitian International Holdings
Category: Injection Molding