Maintenance for Injection Molding Machine Systems

The injection molding machines are generally working for 24 hours a day.

For machines that have been working for a long time, we must do a good job of maintenance work, and strive to find and solve problems before the machine fails. Otherwise, once the machine breaks down, production must be stopped and the machine must be repaired. It will greatly affect production.

Therefore, it is particularly important to do a good job in the maintenance of the injection molding machine. To do well in the maintenance of the injection molding machine, the maintenance content must be classified according to the frequency of possible failures. List the most frequent content in the daily maintenance, the less frequent in the weekly maintenance. By analogy, classify the work content of monthly maintenance and annual maintenance.

After determining the maintenance content, it is best to arrange for a dedicated person to be responsible to ensure that the maintenance work is carried out effectively in accordance with the scheduled arrangement. The necessary records must be done every time the maintenance work is completed. So that it can offer basis for the evaluation of the machine in the future work.

(1) When checking the high-voltage components in the machine, if not necessary, don’t turn on the main power supply.

(2) When changing the mold, avoid the cooling water flow into the electric control box.

(3) Check whether the temperature in the electric control box is too high. Cause it will affect the normal operation and service life of the electronic board.

(4) When changing the relay, we should use the designated voltage relay.

Maintenance of the hydraulic system

The temperature of the hydraulic oil of the injection molding machine should be kept between 30-55 degrees Celsius. If the oil temperature exceeds 60 degrees Celsius, the following problems will occur:

(1) The hydraulic oil has deteriorated due to oxidation.

(2) The viscosity of the hydraulic oil decreases. causing damage to the oil pump, oil leakage and pressure drop. In addition, it decreases the efficiency of the whole machine.

(3) Accelerate the aging speed of oil seals.


(4) Prevent the cooling water from leaking into the system oil tank, and pay special attention to checking whether there is water leakage inside the oil cooler. Clean the inside of the cooler every 6 months or so.

(5) The hydraulic oil must be replaced every 3000-4000 hours of operation for the injection molding machine. When changing the oil, do not mix the new and the old oil. At the same time, twist off and clean the filter in the oil tank.

(6) The directional valve fails because the valve core is blocked by foreign objects. Remove the valve core and clean it with diesel or kerosene (or immerse it in clean hydraulic oil for cleaning). Then, use compressed air to remove the foreign objects.

Maintenance of the clamping part

(1) The machine toggle of the clamping unit has a long working life, but each movable part should be properly lubricated. Otherwise the machine toggle will wear and reduce the life.

(2) Keep the four tie bar clean.

(3) Keep the sliding feet and sliding rails of the moving platen clean and lubricated.

(4) Avoid using molds that request the pressure close to or exceed the working limited.

(5) When adjusting the mold, don’t use the high-speed of clamping .

(6) Control the mold clamping movement stroke position to the most appropriate position. It is to reduce the impact to the machine in each mold clamping.

Maintenance of the injection part

(1) Keep the guide rod of the injection unit lubricated and clean.

(2) Keep the surface of the injection unit clean and dry.

(3) When using the recycle material, a magnetic components must be added to the hopper to prevent metal fragments from entering the barrel.

(4) The barrel temperature reaches the set temperature for about 3 minutes, then start. So that it can ensure that the raw material stayed in the barrel is completely softened. And further prevent damage to the screw.

(5) When the barrel has not reached the preset temperature, do not start the hydraulic motor of the screw.

(6) Use the correct method of replacing plastic and cleaning the melted plastic in the barrel provided by the plastic supplier.

(7) Periodically check all parts of the injection unit, tighten the loose parts, and ensure that the two injection cylinders are installed in balance. So as to avoid damage to the oil seal, cylinder and piston rod.

(8) When the melt temperature is normal and the melt black spots or discoloration continue, check the screw whether the check ring and check seat of the screw are damaged.

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