Injection Molding Machine Maintenance

For Injection Molding Machine Maintenance, which is recommended to clean the oil cooler once of 6 months. Replaced the pressure oil and remove and wash clean the oil screen inside the oil cylinder once after 3000- 4000 hours the injection molding machine runs.

Mechanical part in the Injection Molding Machine Maintenance

The Injection Molding Machine Maintenance of the mechanical part mainly includes template parallelism, thickness adjustment, and a central lubrication system. Mechanical transmission stability and bearing inspection, etc.

• Template Parallelism:  The template parallelism can best reflect the condition of the mold clamping part. If the template is not parallel, it will produce unqualified products and increase the wear of the parts. The movable template, fixed template, guide post, and machine hinge of the injection molding machine should be checked for wear and tear. etc.

• Mold Thickness Adjustment:  The mold thickness should be adjusted from the thickest to the thinnest to see if the action is smooth. This is especially important for long-term use of the same mold. The system composed of the mold adjustment device and the mold adjustment template should be checked frequently. This inspection needs to be done to prevent failure.

• Centralized lubrication system:  Proper lubrication is necessary for all mechanically moving parts. Frequent oil refills or the addition of lubricating grease at the necessary location are recommended for the central lubrication system. When an oil pipe becomes clogged or leaks, it must be promptly replaced. The lubrication for the clamping system is centralized. To make certain that each lubrication point is lubricated, repeatedly pull the manual pump. At least twice per shift, there is a supply of lubricating oil. There should be specified records or checks for the lubrication of the mold adjustment nut, pull rod thread, upper and lower splints, and grease nipples of the injection platform.

• Mechanical Transmission Stability:  The mechanical transmission should move smoothly at all times. Each motion may vibrate and seem uneven if the speed parameters aren’t adjusted properly. This kind of vibration will hasten the mechanical part’s deterioration or loosen the screws that are fastened. The only way to prevent and lessen vibration is to keep the mechanical transmission stable.

• Inspection of the bearing:  If the bearing component makes an unusual noise or the temperature increases significantly while it is rotating, the bearing is worn out and should be inspected, diagnosed, and replaced as soon as possible.

Upkeep of the Hydraulic Component

Hydraulic oil volume, temperature, quality, replacement, oil filter cleaning, and cooler cleaning are all part of the hydraulic part’s maintenance requirements.

• Hydraulic oil volume:  Models of widely used injection molding machines lack an oil volume indicator in the oil tank. Every month, it should be examined, and accurate measurements should be taken. Inadequate measurement will cause the oil to heat up too much and allow air to dissolve into it easily, both of which can lower the oil’s quality. The usual causes of inadequate measurements include leaks, leaks, and oil loss during repairs.

• Temperature of hydraulic oil:  The hydraulic system’s ideal operating temperature is between 45 and 50 degrees Celsius. The hydraulic system is built around the hydraulic oil viscosity that was chosen, but as oil temperature changes, so does the hydraulic oil viscosity, affecting the system’s functioning parts (hydraulic cylinders, hydraulic valves, etc.) and lowering control precision. Low hydraulic oil temperature will increase energy loss and reduce running speed, while high hydraulic oil temperature will hasten the aging of sealing components, causing them to harden and crack.

• Hydraulic Oil Quality:  Hydraulic oil needs to be kept in good shape at all times, which means it should be kept clean, not foggy, and not old. The elements that cause hydraulic oil to become turbid include water and air. It just takes 1% of water to make an effect, yet it is simple to identify when air and water are mixed. Take a portion of the hydraulic oil and place it in a clear container frequently. if the oil contains air mixed in after some time, a cloud-like precipitate will start to develop in the middle of the container, and the top will start to clear. If you’re unsure, you can heat the oil to 100°C and check to see if any steam is escaping. The aging of hydraulic oil is generally difficult to distinguish, but it can be shown from the bottom of the oil tank and the color of the hydraulic oil itself (turning to dark color).

• Replacement of hydraulic oil:  Generally, the hydraulic oil should be replaced once after working for more than 6000 hours. If there is too much water or pollutants, it should be replaced immediately. The specific replacement steps are as follows.

1.Empty the oil tank’s hydraulic oil cost.

2.Make the oil filter clean.

3.Scrub the oil tank’s interior wall (To avoid the dander residue clogging the oil filter’s filter screen, take care not to use rags).

4.After the machine is restarted, add enough oil, if the oil level drops, add more.

5.Start the machine, remove the air from the oil line, and then carry on with your regular production.

• Cleaning of the oil filter:  The oil filter should be cleaned frequently, once every three months or the filter screen should be replaced to keep the oil suction pipe of the hydraulic pump unobstructed.

• Cooler cleaning: The cooler should be cleaned every six months or 5000h, the internal blockage of the cooler will affect the cooling effect.

Injection Molding Machine Maintenance of Electrical Control Part

The electrical control part mainly includes a power connection, motor, heating tube, thermometer, electromagnetic relay, contactor, etc.

• Power Connection:  A connection to a three-phase, four-wire power source is possible for the device. The grounding resistance must be less than 10, and the ground wire must be securely attached. High temperatures or sparks will result from improper or sloppy wire connections at the power supply connection location. When it is damaged, vibration can easily loosen the connection on the electromagnetic contactor, which leads to a poor connection between the contact wires, heat, and burning joints. Check and tighten the wire connection regularly.

• Motor:  By the rules, the motor must turn in a clockwise direction. Typically, air cooling is used to cool the motor. A buildup of too much dust will make it harder for the motor to dissipate heat. Therefore, it needs to be cleaned once a year to ensure that the motor can dissipate heat effectively.

• Heating cylinder:  To guarantee efficient heat transfer, the screws holding the heating cylinder to the barrel should be checked and tightened regularly.

• Thermometer: A thermometer is also called a temperature controller, The temperature signal on the barrel is collected by the thermocouple. You should regularly check whether the installation position is appropriate and whether the installation contact is good. Set the temperature of the thermometer and adjust and correct the actual temperature, otherwise, it will affect the temperature measurement and control, affect the quality of defective products, and product stability.

• Electromagnetic relays, contactors:  Electromagnetic relays mainly control relays, time relays, etc., and contactors are mainly AC contactors. Contactors or relays or other time relays used in the electric heating part, due to frequent actions, wear out quickly. If overheating or noise is found, it means that there is a fault or damage, and it should be replaced asap

Cleaning of Nozzle, Screw and Barrel

The material slip and screw should be cleaned when the goods injected by the injection molding machine are contaminated, the replacement raw materials have many colors, and there are many injections. You can choose between partial cleaning and thorough cleaning depending on the level of pollution.

Nozzle Cleaning: 

When the product has uniform stains in different places, it is indicated that it is caused by colored residue flowing out along the nozzle channel or the gate in the mold. At this time, the nozzle should be checked and cleaned. The general cleaning process is as follows.

1. Before cleaning, use polyolefin resin with high thermal stability or a special barrel cleaning agent to clean the residual melt in the barrel (inject several times into the air).

2. Return the injection device to the rearmost position.

3. Turn off the heating system of the barrel, and untie the connecting plug of the heating ring and the thermocouple joint.

4. Remove the barrel cover.

5. Move the screw to the front end (manual operation).

6. Turn off the main power.

7. Loosen the fastening screw of the barrel, and remove the barrel and nozzle. To prevent burns, wear protective gloves and goggles during the operation.

8. Drop mold release agent from the thread side of the nozzle to the space between the material and the inner wall, take out the residual molten material in the nozzle, clean the nozzle and the barrel with a copper wire brush, and then gently polish and wipe the surface to be cleaned with a fine gauze cloth. If the residual melt cannot be cleaned up, it can be heated and softened in an oven and then taken out for cleaning. At the same time, check the screw head for damage.

9. After cleaning, reinstall the pieces.

Thorough barrel and screw cleaning

The product has irregular and fine stains, which typically appear on the barrel and nozzle sealing surfaces, the sealing surface of the screw and the screw head, as well as the feeding port, screw, check ring, barrel head, etc. The barrel and screw should be completely cleaned at this point (The barrel and screw assembly have to be taken apart before cleaning).