Based on your previous experience focusing on hot runner cleaning, repair, and subsequent commissioning, common reasons for hot runner system commissioning failures can be categorized into five main types:
I. Hardware Connection Issues: Incorrect wiring between the temperature control card and the hot runner system/temperature sensor leads to signal transmission interruption and abnormal temperature acquisition.
The power supply voltage/current does not meet the hot runner specifications, resulting in insufficient heating power and inability to reach the set temperature.
Damaged heaters or thermocouples cause heating or temperature measurement malfunctions, directly leading to commissioning failure.
II. Parameter Setting Issues: Incorrect initialization parameters on the temperature control card; the temperature range, heating power, and control mode do not match the actual parameters of the hot runner.
Inappropriate preheating temperature settings, failing to reach 20-30°C above the plastic melting temperature, or insufficient preheating time (less than 1 hour), resulting in incomplete melting of residual material in the runner.
Reversed temperature adjustment sequence for the main runner, branch runners, and nozzles causes sudden temperature changes in localized areas, leading to material solidification and blockage.
III. Installation and Compatibility Issues: The hot runner system is incompatible with the injection molding machine specifications; nozzle size and installation interface are misaligned; gate alignment is insufficient.
The hot runner plate mounting surface is uneven; seals are not properly installed, leading to potential leakage and inability to maintain pressure during commissioning.
The hot runner cooling water channel layout is unreasonable; the water channels are too close to the heating elements, excessively carrying away heat and causing temperature instability.
IV. Material and Process Issues: The characteristics of the plastic material to be processed are incompatible with the hot runner temperature setting; the material's melt temperature deviates significantly from the actual controlled temperature.
Injection speed and pressure parameters are set improperly during the trial molding stage; the plastic does not flow smoothly within the runner, resulting in carbon buildup and residue buildup.
V. Calibration and Maintenance Issues: The temperature sensor has not been calibrated; the measured temperature value deviates significantly from the actual temperature, causing misjudgments by the temperature control system.
The hot runner has not been periodically calibrated for a long time; the temperature control card's accuracy decreases; temperature fluctuations exceed the allowable range; and stable operation cannot be achieved during commissioning.
