Common faults of the self-diagnostic function of a hot runner system mainly include thermocouple disconnection, open or short circuit in the heating circuit, temperature exceeding limits, abnormal temperature drift, and voltage abnormality. These faults will trigger corresponding alarm codes to help operators quickly locate the problem.
The following are the main fault types and their manifestations and causes:
Thermocouple disconnection or failure (often reports E01)
Symptoms: Abnormal temperature display, inability to read, or a constant value of 0/maximum.
Causes: Loose wiring, damaged sensor, signal interference, or aging due to prolonged high temperature.
Impact: Loss of temperature feedback may lead to uncontrolled temperature control, causing material degradation or uneven filling.
Open circuit in the heating circuit (often reports E02)
Symptoms: A certain area continues to fail to heat up, and the current detection is zero.
Causes: Broken heating wire, poor terminal contact due to oxidation, worn cable, or loose connector.
Impact: Causes a drop in temperature at the corresponding hot nozzle or manifold, resulting in molding defects such as cold material and short shots.
Heating Circuit Short Circuit (Commonly Reported as E03)
Symptoms: Abnormal current surge, fuse blows, or circuit breaker trips.
Causes: Insulation damage leading to short circuit between positive and negative terminals, moisture intrusion, or improper installation causing circuit compression.
Impact: May burn out the temperature control module, posing a safety hazard; immediate shutdown and inspection are required.
Temperature Exceeding Limits (Commonly Reported as E04)
Symptoms: Measured temperature deviates from the set value by more than ±5℃.
Causes: PID parameter misalignment, insufficient cooling, ambient heat accumulation, or external power fluctuations.
Impact: May cause material charring and dripping, affecting the appearance and performance of the product.
Temperature Abnormal Drift (Commonly Reported as E05)
Symptoms: Temperature rises or falls drastically within a short period (e.g., >10℃ within 10 seconds). Causes: Overly aggressive control algorithm response, slow sensor response, uncompensated shear thermal abrupt changes.
Impact: Reflects poor system stability, potentially indicating impending sensor failure or control malfunction.
Abnormal Power Supply Voltage (often reports E06)
Symptoms: Frequent system restarts, flashing alarms, or communication interruptions.
Causes: Power grid fluctuations, startup of shared high-power equipment, excessive line voltage drop.
Impact: Affects the stability of the entire control system, potentially leading to data loss or module damage.
The above faults can be viewed in real-time via the HMI interface using alarm codes, and analyzed in conjunction with event logs. It is recommended to regularly check line connections, calibrate sensors, and update control parameters to ensure the long-term effective operation of the self-diagnostic function.
