3 main points teach you Injection molding machine preventive maintenance

2022-07-15 15:46:07

The injection molding machine is the main equipment in the production of plastic products. The injection moldign machine is a key indicator in the overall production that its stability greatly affect whether the order can be delivered on time, so if it has any problems, the injection molding plants may have loss and trouble.

An injection molding machine is like a good partner, which has been able with customers for many years, working hard together to create the value. However, do you really know how to cherish and maintain this good partner? The injection molding machine is a continuous, stable, high-pressure operation and production equipment, so it must be careful attention. A good preventive maintenance concept can not only maintain stable production, but just like a chef should maintain a kitchen knife to make it sharp to increase production capacity to create more value for you.

Not sure what to be careful attention? The following 3 points teach you how to do preventive maintenance.

1.  Regular maintenance

No matter what injection molding machine components are, regular maintenance is the basic, which can be classified into weekly, monthly, quarterly, and yearly from simple to depth maintenance. However, in addition to regular maintenance, observation is also a very important point. When doing maintenance, it is best to observe the equipment with a firm and rigorous attitude, which can also reduce the occurrence of problems with the injection molding machine.

The injection molding machine can be classified into four directions for observation: injection unit, clamping unit, hydraulic system, and electrical system.

Injection unit:

The injection unit is mainly composed of a hydraulic motor, injection double cylinder, screw barrel set, electric heating component, etc. It is an important core system of an entire injection machine. The power of the hydraulic motor pushes the screw of the screw barrel set to rotate, and then the plastic is plasticized by the electric heating component and then injected into the mold to achieve the overall operation process of the injection unit. Therefore, special observations should be taken on the injection unit.

Clamping unit:

The parallelism of the movable platen and the fixed platen will directly affect the accuracy of the injection molding machine. The toggle rod shaft and toggle bushing are often subjected to high pressure and rotational force, resulting in frictional heat, shear stress and compressive stress. If there is no high-quality lubricants, build oil film, easy to bite, wear, causes uneven force and affects the clamping force and the parallelism of the machine platen.

Hydraulic system:

The hydraulic system of the injection molding machine is composed of a pump, a motor, a brake cylinder, a directional valve, a flow valve, a pressure valve, a safety valve, a cooler, a hydraulic motor, etc. The circuit design and control are reasonable, and the appropriate oil temperature is 40°C ~ 50°C and good oil quality is the basic condition of oil pressure.

Electrical system:

The parts of the electrical system in the injection molding machine are usually easy to loosen due to vibration. If they are not treated, they will easily burn the parts due to excessive current, which will affect the stability of the action.

The following content teaches you the regular maintenance that should be done weekly, monthly, quarterly and annually. Only the actual implementation can 100% ensure that the machine can operate better.


  1. Check the electric heater, high-pressure hoses and hose joints for oil leakage, screw parts, and electric heating of nozzles.
  2. There are pigments and additives in the plastic. When replacing the raw materials, check and wipe off the residual pigment.
  3. Remove the waste oil accumulated in the injection molding machine.
  4. Clean the oil circuit board and hydraulic components.
  5. Cleaning of electrical components.


  1. Check the ground wire, electrical circuit, movable platen and injection double cylinder sliding feet.
  2. Machine grease maintenance.
  3. Cleaning of the oil filter.


  1. Regular inspection of hydraulic oil.
  2. Check the various movable points of the machine to see if there is any abnormal wear.
  3. Replacement of oil filter (optional).


  1. Inspection of motor and ventilation system.
  2. Measurement of resistance to insulation.
  3. Oil seal and oil cylinder function test, if damaged, replace it with a new one.
  4. Clean and organize the cooling water system, and replace it with a new one if it is damaged.

2. Use the correct industrial oil

The lubrication of the machine part can prevent the wear of the machine parts, make the movement smooth and reduce the working noise.

Hydraulic oil:

Hydraulic oil must be able to transmit effectively and have sufficient mechanical lubricity. If the hydraulic oil is used improperly, the hydraulic parts in the injection molding machine will be easily worn and the pressure stability will be poor. Therefore, the selection of the hydraulic oil must have the following characteristics:

  1. Resistant to compression.
  2. Appropriate viscosity.
  3. It is safe to use for a long time (no chemical changes).
  4. Has good lubricity.
  5. Suitable for various oil seal materials.
  6. Less playability and excellent fire resistance.
  7. Non-toxic.
  8. Stable to oxidation (no rust and corrosion).
  9. Good high temperature stability.

Lubricating oil:

  1. The lubricating oil must be clean and free of used recovered oil.
  2. The oil filter of the oil filling port should be cleaned regularly to ensure the lubrication effect.
  3. Pay attention to whether the supply of the lubrication system is normal every day.
  4. The manual grease gun is relatively simple to use, just press the grease into it.
  5. Where there is a grease hole, a grease gun needs to be injected to ensure the lubrication effect.

3.  Clean up the cooling system
If the cooler is not cleaned regularly, it is easy to affect the cooling efficiency due to the accumulation of scale, resulting in an increase in the power consumption rate of the machine.

Cooler tube cleaning:

  1. Remove the cover, use nylon preparation or clean preparation to wash the dirt inside cooler, or use 0.6~0.8% hydrochloric acid to wash circulated inside cooler under oil cooler assembled well.
  2. Remove the two extremities covers and use air gun to clean out the circulated water inside the copper pipe.
  3. Lock the two extremities covers and oil seal to original condition, and connect cooling water.


  1. For fresh water only.
  2. The maximum operating pressure on the oil side is 1.0Mpa, and the maximum operating pressure on the water side is 0.5Mpa.
  3. In the season when the cooling water may freeze, the water in the heat exchanger should be drained when not working.
  4. Clean the inside (water side) of the heat exchange tubes at least every six months to maintain good cooling.
  5. Better to use soft water (water without mineral) for cooling water. Clean the sediment periodically inside the cooler, if the hard water is used.


Having the correct maintenance concept and establishing good maintenance habits can prolong the life of the injection molding machine, reduce the possible losses caused by downtime, and save maintenance costs.

HUARONG, as the Injection Molding Machine Manufacturing Expert, emphasizes sturdiness, durability and reliability. With the usual maintenance, the machine will be able to exert 100% capacity and create value beyond your expectations.

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