Troubleshooting methods for common injection molding machine malfunctions

 

1. Loose or burnt-out wiring of the proportional valve on the oil pump – Check if the proportional pressure valve is energized.

2. Impurities clogging the oil port of the proportional pressure valve on the oil pump – Remove the proportional pressure valve and clean the impurities.

3. Impure pressure oil, with debris accumulating on the surface of the oil filter, preventing pressure oil from entering the pump – Clean the oil filter and replace the pressure oil.

4. Internal oil leakage in the oil pump, caused by prolonged use, internal wear, or damage due to impure pressure oil – Repair or replace the oil pump.

5. Oil leakage from the oil pump barrel, oil hose, and connectors – Eliminate the leak.

6. Oil valve jammed – Check if the oil valve core is moving normally.

II. Melting Cylinder Temperature Cannot Be Controlled

1. Temperature cannot be controlled; check if the contacts of the heating contactor are stuck, and if the thermocouple wires are loose or damaged.

2. If the temperature fails to rise, check the electrical control box for a tripped circuit breaker, contactors, relays, voltage, blown fuses, and burnt-out heating coils.

3. Check if the thermometer is damaged.

III. Failure to Lock the Mold

1. Check if the front safety door is closed, and if the safety door limit switch is engaged and disengaged. Check for loose or damaged wiring.

2. The locking solenoid coil may be stuck in the valve, obstructing the valve core – clean or replace the locking/opening control valve.

3. The directional valve may not reset – clean the directional valve.

4. The ejector pin cannot return to its original position – check if the ejector pin operation is normal.

5. Check if the origin of the electronic ruler for locking and opening the mold on the computer controller has changed, and if the locking position has terminated.

6. Check if the pressure gauge is activated.

7. Press the locking button and check if the display shows a locking signal or other signals and alarms.

8. Check if the mold clamping position, speed, and pressure are properly adjusted.

9. Check if the mold clamping piston rod is broken.

IV. No Injection

1. The injection solenoid coil may be burnt out, or foreign objects may have entered the directional valve, jamming the valve core – clean or replace the injection valve.

2. Pressure too low – increase the injection pressure.

3. Injection temperature too low – adjust the temperature gauge to raise the temperature to the required point. If adjusting the temperature gauge still cannot raise the temperature, check if the heating element and fuse are burnt out or loose.

If broken, replace them immediately.

4. Loose or poor contact wiring in the injection combination valve – properly connect the combination switch wires.

V. Melting screw turns, but material does not enter the barrel

1. Melting back pressure is too high, back pressure valve is damaged or improperly adjusted – adjust or replace the melting back pressure valve.

2. Insufficient water supply, leading to excessively high temperature, obstructs the entry of adhesive particles into the screw – Adjust the water supply and remove any adhered adhesive blocks. Check if the water supply ring is blocked or lacks cooling water.

3. No material in the hopper – Add material.

4. Is the melting cylinder temperature too high?

VI. Injection Station Does Not Move

1. The injection station's movement limit switch is pressed by the adjustment block – Adjust.

2. The coil of the injection station's movement solenoid valve may be burnt out or a foreign object may be stuck in the directional valve, preventing the valve core from moving – Clean or replace the solenoid valve.

3. Check if the injection station's forward speed and pressure are improperly adjusted.

4. Check if the voltage (DC+24V) output from the directional valve on the I/O board is normal. If abnormal, check if the corresponding output transistor or relay is damaged.

5. Press the injection station button and check if the computer display shows the injection station front signal, or other signals and alarms.

6. Check if the pressure gauge is moving.