Maintenance of Injection Molding Machines

Maintenance of Injection Molding Machines

Injection molding machine maintenance:  There are many brands and models of molding injection molding machines. The imported injection molding machine brands include Sumitomo, Toshiba, Mitsubishi, and Hishiya from Japan and Taiwan; the domestic injection molding machine brands include: Haitian, Borch, and Yizumi. No matter what brand of the machine it is, from the perspective of the manufacturer, the production of machinery and equipment must not only create brand awareness and be recognized by the majority of consumers but also ensure that the quality of the components produced must meet various national standards and provide after-sales service, Tracking debugging and corresponding equipment maintenance, so that consumers have no worries when using it.

The more important thing is the user. The purchased injection molding machine often needs continuous operation to ensure stable production.

Therefore, the performance and quality of the injection molding machine are important. Still, regular maintenance and maintenance of the injection molding machine in normal operation is an effective way to ensure the improvement of production efficiency.

The so-called maintenance and maintenance of the injection molding machine: is to regularly stop and overhaul all parts of the machine equipment to avoid unexpected failures during the machine operation and affect production, which can prolong the continuous operation time of the machine.

Carrying out planned overhaul can find hidden tooling components, replace aging and faulty parts in time, prevent chain faults, maintain and maintain the machine, ensure the normal operation of the equipment, and improve the injection molding machine. Long-term use performance, processing enterprises equipped with injection molding machines, injection molding machines are the main equipment for the production of products, and regular inspection and maintenance of the machine is the guarantee to ensure the machine’s durability.

The injection molding machine mainly consists of three parts: the electrical, the hydraulic, and the mechanical parts. These three parts are very closely related, rely on each other, and control each other, like the three major veins of the human body. Its initiative can prevent the failure of one part from affecting the continuous operation of other works. Various electrical signals are sent to each part of the injection molding machine; the oil pressure part is the energy supply part, and the mechanical part is the action execution part.

Maintenance of Injection Molding Machines (2)

First, the electrical part:

1. Regularly clean the circuit and components in the electrical box with an electrical cleaning agent to remove dust and foreign matter so that the components in the electrical box are clear and easy to check.

2. Shut down according to the specified time to check whether the interface between the electrical box and all the terminals of the injection molding machine is tight. Due to the machine’s vibration running for a long time, it is easy to cause the originally fastened terminals to loosen, and the loose connectors will cause poor contact of the terminals when the machine is running. Electric sparks or temperature rise terminal aging and damages components.

3. The electrical box motor is air-cooled and generally equipped with a ventilation fan to promote airflow. The purpose is to discharge the heat generated by the motor during long-term high-speed operation. Regularly clean the ventilation fan net cover’s dust screen and the motor casing’s dust. The ventilation fan must be replaced in time if it fails to operate. Otherwise, the high temperature in the electrical box will affect the service life of other components.

4. Contactors and relays An injection molding machine usually uses 4-6 types of contactors and relays according to the needs of the heating part. When the power is turned on, the contacts of the contactors and relays will be closed and disconnected according to the required temperature. Open, long-term, and frequent pull-ins and break-off will cause wear and aging of the contacts, the phenomenon that the phenomenon does not break after pull-in, or the coil is broken, and the pull-in cannot be closed. The temperature does not break after the pull-in, which will affect the thermostat. Set the temperature and need to be replaced in time.

5. Thermostat, thermocouple, and heating coil: The temperature controller measures and controls the heating temperature of the heating ring. The heating parts on the heating sleeve of the injection molding machine are divided into three parts: the front end, the middle end, and the injection top. The heating of each part has a corresponding temperature, which is reasonable. The temperature can ensure the production of qualified products. The thermocouple controls the temperature of the thermostat and the heating coil. When the temperature reaches the set value, the thermocouple is disconnected, and the heating coil is powered off to stop heating so that the thermostat’s temperature remains stable. When the temperature is lower than the set value, the thermocouple is energized, the contactor is closed, and the heating coil is heated by electricity to make the temperature return to the set value.

The sensitivity of the thermostat is regularly checked. The thermocouple and the heating coil are used due to long-term heating. , easy to age and damage, use a multimeter to check whether the thermocouple of the heating coil can be used normally, the heating coil and the thermocouple are fastened on the heating sleeve, and regularly check whether the interface is fastened to ensure effective heat transfer. The connecting wire is heat-resistant, so The heating cartridge is often moved, and the connecting wires on the heating cartridge should be cleaned regularly to ensure safe operation.

6. Control panel section With the rapid development of science and technology, the development technology of injection molding machines has also changed by leaps and bounds. The operation panel of the injection molding machine has developed from the original manual button to the operation of the digital display panel. Temperature and humidity, the shock resistance of the installation, and the interference of external high-frequency signals put forward higher requirements. Record and control the temperature and humidity of the working environment and regularly check the impact of the working environment on production. If the humidity is high, it is easy to cause the work program to fail. The action is chaotic. When the work fails, the alarm will display a fault alarm. The emergency stop button can prevent the machine from malfunctioning.

7. Solenoid valve and regulator filter: A Solenoid valve combines electrical and mechanical. It is often used in the manipulator device of injection molding machines. The air source supplied by the solenoid valve is adjusted to about 6KG through the pressure-regulating filter. The filter filters the air source, and the pressure-regulating filter is cleaned regularly. Make the air pressure clean and stable. When the solenoid valve is powered on, it sends an electrical signal to supply air pressure. The central axis of the solenoid valve moves back and forth to supply various actions of the manipulator. If the air pressure is not clean, the sealing ring of the solenoid valve is easy to age after long-term use. It can be cleaned with kerosene. Replace the ageing sealing ring to make the solenoid valve work normally.

Second, the hydraulic part:

Regularly check whether the oil in the oil tank of the injection molding machine is sufficient. If the oil is insufficient, the oil temperature will rise when the machine is running, and air will dissolve into the oil, affecting the oil quality and the normal operation of the oil pressure system. Check the oil in the oil tank every week. Quantity, replenish the oil quantity in time. Regularly check the oil pipe joints, whether there is oil leakage at the screw joints, and replace the oil pipes prone to age in time to avoid bursting after long-term use.

In case of oil leakage, check the hidden dangers of oil leakage in time and deal with them in time to ensure that the oil circuit and the outside of the fuel tank are clean. To ensure the relative stability of the working environment of the hydraulic oil, the ideal working temperature of the hydraulic system should be between 45-50 degrees. If the temperature changes, it will affect the system’s components and the hydraulic valve’s working accuracy.

The abnormal performance is that the hydraulic valve has an electrical signal, but there is no action, resulting in no other related actions. Too high an oil temperature will accelerate the aging and fracture of the sealing ring in the hydraulic valve. When the hydraulic valve is faulty, the hydraulic valve can be disassembled and soaked in kerosene and replaced with a new sealing ring. Aged seals. The hydraulic oil needs to be replaced regularly after a period of use.

The color of the hydraulic oil used for a long time will become darker, and oxidation will occur. The oil concentration must be checked regularly to ensure the quality of the hydraulic oil used in the injection molding machine.

To ensure the cleanliness of each oil branch, an oil filter is installed in the oil circuit of the injection molding machine. It is very necessary to clean the oil filter every 3 months. The oil filter can be soaked in kerosene to remove the debris and check the oil filter simultaneously. Whether it is damaged, usually the specification of the stainless-steel mesh in the oil filter is not more than 200 mesh; replace the oil filter if necessary.

When the product is produced and formed, water is required to cool the product as soon as possible to facilitate separation. The cooling system is also very important when running the injection molding machine. The cooling system’s pipelines, joints, and joints are prone to aging. Regularly check the components of the cooling pipeline. Replace them in batches to ensure that the cooling pipeline is unblocked.

Finally, the mechanical part:

  1. Reasonably adjust the parallelism of the templates. If the templates are not parallel, it will directly affect the quality of the produced products and the wear of the machine equipment and molds. The parallelism of the template can be reflected by the movement of the mold lock tail plate and the appearance analysis of the product, and it needs to be adjusted step by step by experienced operators.
  2. Regularly clean the screw and barrel. Long-term use of the screw and heating barrel will cause a slow melting pulse and spots or black spots on the melting material, directly affecting the product’s quality. Regular barrel cleaning with stearic acid can clean the screw on the screw. Foreign matter, polished with sandpaper.
  3. The operation of all mechanical parts must have a supply of lubricating oil. Regularly add lubricating oil to the lubrication system to ensure the cleanliness of the oil circuit and avoid wear and aging of the mechanical parts, which is very important for the mechanical operation of the injection molding machine.
  4. Adjust each action’s coordination to ensure the machine’s normal operation. If the operating speed and time of the machine are unreasonable, it will cause strong vibration of the mechanical part and directly damage all parts of the machine.
  5. Regularly check the use effect of the bearing, replace it in time when abnormal noise is found, and add lubricating oil.
  6. The V-belt driven by the motor is easy to wear due to long-term rotation, so it should be replaced regularly, and the dust and foreign objects around the motor should be cleaned in time to ensure a clean working environment.


The service life of an Servicing injection molding machines depends not only on the high-quality guarantee of the manufacturer but also on the careful maintenance and maintenance of the user to improve its reliability and durability.

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Frequently Asked Questions

Daoben has the SOP (Standard Operation Procedure) and all the production steps must follow up this SOP. Every machine needs at least automatic running over 72 hours and must be inspected carefully before shipment.

Actually, the delivery time of the machines is depended on the machine options. Normally, the delivery time of a standard machine could be within 1-2 months.

12 months warranty after shipment for mechanical parts, hydraulic parts, and electric components excluding the screw and barrel 6 months (not including use for recycled material or reclaimed material).

Yes, Daoben will provide one set of standard spare parts to the customer including a heater, filter, screw head, screw washer, checking ring, sealings, etc.

Surely, we have experienced technical engineers for oversea service, they would help you install machines and support training to workers also. Currently, we provide visits online by video call for COVID-19.

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