Common Faults and Treatment Methods of Injection Molding Machines

SS Machinery

Composition of Injection Molding Machine

The injection molding machine is mainly composed of four parts: mechanical part, electronic part, electrical part, and hydraulic part. In addition to the four parts, there is an auxiliary part.

1. Mechanical part:

mainly composed of clamping part, injection part, and other auxiliary parts.

Clamping part: related to the mold opening cylinder, double toggle twisting mechanism, coring column, template core.

Glue injection part: there are injection seat, injection cylinder, barrel, screw, glue motor, hopper, heating element, etc.

Auxiliary parts: related protection devices such as racks, safety doors, protective covers, etc.

2. Electronic part:

program control electrical appliances, microcomputer control, 2/0 interface circuit and drive circuit.

3. Electrical part:

It is mainly composed of control electronics, oil pump motor, electric heating circuit, power supply circuit, etc.

4. Hydraulic part:

mainly composed of oil receivers, oil circuit, and various oil valves. Oil hydraulic valves include proportional pressure valves and proportional flow valves, as well as various electromagnetic control directional valves, relief valves, etc.

5. Auxiliary part:

mainly composed of the cooling circuit, lubricating oil circuit, and safety device.


Common Fault Causes and Treatment Methods

Malfunction Reason Approach
1. The motor does not run 1. The fuse of the electric power supply is blown; Replace insurance.
Repair or replace related accessories.
2. The start button connector is bad;
3. The overload relay trips;
4. The main circuit is faulty and the breaker is broken.
2. Buzzing and non-rotating Lack of phase Check the power supply.
3. The oil pump is abnormal 1. Inhale air on the suction side; 1. Repair the joints on the suction side.
2. Clean the filter.
3. Check and repair the oil pump.
4. Add enough oil.
2. The oil filter is blocked;
3. There is abrasion in the pump;
4. The oil level is too low.
4. No action response 1. The total pressure valve is faulty; 1. Repair the total pressure valve and amplifier board.
2. Check and repair the connector.
3. Install the electromagnetic coil.
2. The amplifier board is faulty;
3. The connecting flange of the motor and the oil pump is faulty;
4. The solenoid coil of the servo valve is glued off.
5. Cannot close the clamping 1. The top back is not in place; 1. Check whether the refund is terminated.
2. Check each circuit, oil circuit and mechanical insurance of the safety door.
3. Check and repair the power of the manipulator.
4. Check the position ruler.
5. Check whether the valve body has power supply and whether it is stuck.
2. The safety door is not closed properly;
3. The manipulator did not give the mold closing signal;
4. Position ruler data failure;
5. The directional valve does not operate.
6. Can not open the mold 1. The directional valve is faulty; 1. Check the valve body.
2. Adjust mold opening and pressing.
3. Overhaul the crank arm.
4. Check the position ruler.
2. Insufficient pressure;
3. Mechanical card hole of the curved hand;
4. The position ruler is faulty.
7. Unable to eject 1. The manipulator has no ejection signal; 1. Check the manipulator.
2. Check whether the mold opening is completed.
3. Overhaul the solenoid valve.
2. The mold opening is not completed;
3. The solenoid valve is faulty.
8. The pressure does not rise or the temperature rises slowly 1. The pressure regulating valve is not tight enough; 1. Remove and inspect.
2. Exhaust.
3. Overhaul.
2. There is air inside the hydraulic cylinder;
3. The pressure regulating valve is faulty.
9. Cannot be injection molded 1. Poor operation of solenoid valve; 1. Check the solenoid valve.
2. Check the safety valve.
3. Check the nozzle.
4. Check the temperature of each section.
2. The pressure regulating valve is defective;
3. Foreign objects block the nozzle;
4. The nozzle is too cold and the temperature of the material tube is low.
10. Cannot add materials 1. Defective solenoid valve; 1. Check the back pressure valve.
2. Check the temperature.
3. The screw is broken or not slipping.
2. Poor adjustment of back pressure;
3. Poor temperature of the material pipe;
4. Melting glue moves, but does not cut the material.
11. The electric heating is abnormal 1. Breaker failure; 1. Replace damaged parts.
2. Repair the wires.
2. The heating ring is broken;
3. The thermocouple is broken;
4. The wire is short-circuited or grounded.
12. Excessive oil temperature and oil leakage 1. The working pressure is super high 140KGF/CM2; 1. Check the pump and reduce the viscosity.
2. Add enough hydraulic oil.
3. Clean the cooler.
4. Tighten the screws.
2. The oil pump is worn or the oil viscosity is too high;
3. Insufficient oil;
4. The cooler is blocked;
5. The cylinder screws are loose.


The above content is a common injection molding machine problem, I hope it helps you. For more information, please contact us.

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