Troubleshooting and Resolving Unstable Injection and Pressure Fluctuations in Injection Molding Machines
Fluctuations in injection pressure can lead to short shots, sink marks, and dimensional inconsistencies, significantly increasing defect rates. When using hydraulic servo injection molding machines, troubleshooting should be conducted systematically across three areas: hardware, the hydraulic circuit, and process parameters.
1. Hydraulic Circuit Filter Clogging
Accumulated debris in suction or return filters causes insufficient oil supply and pressure instability. Clean filters every shift; if the oil turns black or contains water, replace it promptly with the appropriate hydraulic oil to ensure smooth flow.
2. Hydraulic Hardware Malfunctions
Pressure sensor drift, solenoid valve sticking, servo pump aging, or leaks at hose fittings can all cause continuous pressure loss. Regularly calibrate sensors, replace worn valves and seals proactively, and eliminate leak points.
3. Raw Material and Barrel Issues
Material mixing, moisture absorption, or bridging in the hopper can cause intermittent feeding; damaged heater bands result in uneven melt. Dry the raw materials, inspect the feeding mechanism, and replace damaged heating components.
4. Improper Process Parameters
Excessive spans in single-stage holding pressure or overly rapid pressure ramp-up/down can cause pressure surges. Implement multi-stage injection and holding pressure profiles and slow down pressure transition rates to align with the servo system's smooth pressure control capabilities.
5. Lack of Routine Maintenance
Continuous production without timely lubrication or dust removal can lead to dust accumulation and overheating in servo drives, causing output anomalies. Regularly clean electrical cabinets and standardize daily hydraulic circuit inspections to maintain stable servo system output.
After systematically addressing these issues, injection pressure stabilizes, product consistency improves, and losses associated with downtime and machine adjustments are reduced.
