A Clean lubrication system of injection molding machines needs to check and maintain hydraulic oil, clean oil pipes, and connectors, use the appropriate cleaner, install filter and flushing board, and regular inspections and maintenance.
On the topic of How to clean the lubrication system of injection molding machines? We will analyse professionaly from five aspects.You can refer to the below steps for cleaning the lubrication system of injection molding machines:
- check and maintain hydraulic oil
- clean oil pipes and connectors
- use the appropriate cleaner
- install filter and flushing board
- regular inspections and maintenance
Follow us, we will descripe the details as below:
Check and maintain hydraulic oil
First, ensure the normal operation of the hydraulic system of the injection molding machine and maintain a good lubrication state. Check the oil level of the liquid pressure oil regularly, and replenish or replace the hydraulic oil if necessary. At the same time, monitor the state of the hydraulic filter and replace it in accordance with the manufacturer’s advice.
Oil Level Check
Check the hydraulic oil tank oil level regularly to ensure it is not below the centerline of the level gauge. If it is insufficient, add new oil of the same brand (do not mix old and new oil).
When humidity is high, check the oil concentration daily to prevent water from entering and clogging the filter.
Oil Quality Assessment
- Observe the color of the hydraulic oil: A darker or blacker discoloration indicates oxidation and requires replacement (oxidation is inevitable after long-term use).
- Monitor the oil temperature: Maintain a temperature between 30-50°C (above 60°C accelerates oxidation, reduces viscosity, and damages the pump and seals).
- Check for foam: If foam is present, check for leaks in the hydraulic system and the hydraulic pump suction line.
Leaks and Sealing
Check the hydraulic system for leaks daily, tighten loose joints, and replace worn seals/oil seals.
Check the cylinder seals regularly. If worn, clean the cylinder with kerosene and replace with new ones.
Clean oil pipes and connectors
Regularly check whether the hydraulic hose and connectors have signs of wear, leakage, or damage. If you find it, replace or repair it in time to avoid mechanical wear caused by insufficient lubrication.
System Preparation and Safety Measures
- Turn off the lubrication system power and wait for the equipment to cool (to avoid the risk of high-temperature operation).
- Close the throttle valve and all solenoid valves in the system to isolate the oil supply.
Drain the old lubricant.
Place an oil pan at the drain port and thoroughly drain the old oil from the lubrication system, ensuring no residue remains.
Physical Inspection of Pipelines
- Inspect the oil pipes for blockages, leaks, or damage. Tighten loose connectors immediately and replace damaged pipes. Check the seals of the oil pipes and connectors weekly.
- Confirm that all pipes are sized correctly and connected correctly to avoid contamination from improper installation.
Chemical Cleaning
Inject a specialized cleaning agent (such as carbon tetrachloride or sodium hydroxide solution) into the system. Start the system to circulate the cleaning agent through all lubrication points to remove impurities. Complex systems can undergo an acid cleaning process:
- Immerse in a hydrochloric acid solution (10-15% by mass) for 20-30 minutes (at 40-50°C), then rinse with warm water;
- Subsequently, soak in an ammonia solution (1% by mass) for 10-15 minutes to thoroughly remove any oil contaminants.
Flushing and Drying
After draining the cleaning agent, repeatedly flush the system with clean water until no residue remains.
Blow out the drain pipe and oil lines with filtered compressed air to ensure internal dryness.
Connector Maintenance
- Lubricate valve stems: Use a graphite-based lubricant to prevent sticking.
- When reinstalling oil lines, ensure that the protective nut is aligned with the pipe hole to avoid misalignment and leakage.
System Recovery and Testing
Add new, clean, and impurity-free lubricant and regularly check the oil tank level.
After starting the system, inspect all lubrication points for oil leakage and verify that the oil lines are unobstructed.
Use the appropriate cleaner
When cleaning the lubrication system, clean and easy-to-dry solvents should be used to clean the fuel tank and remove the solvent residue with filtering air.
Maintaining lubricant cleanliness is paramount
Use pure, impurity-free lubricant and regularly check oil lines for blockages and leaks. Contaminated lubricant can cause mechanical wear, so ensure that the central lubrication system’s oil lines are unobstructed and the oil pump filter is clean.
Physical cleaning is a priority
- Regularly check the oil level and oil line condition (replace oil lines if clogged)
- Clean the lubrication pump filter
For deeper cleaning
Refer to the methods for similar systems:
Disassembly and cleaning can use solvents (such as methylene chloride). But this requires professional personnel and proper ventilation and fire prevention.
Avoid inappropriate cleaning agents
Avoid using corrosive or abrasive cleaning agents to prevent component damage. The same principles should be followed when cleaning lubrication systems.
Install filter and flushing board
Install oil filters in the oil circuit to protect the valve supply line and pressure line. Install the flushing plate on the streaming device to replace the precision valve, such as an electrical service valve.
Replacing Precision Valves
Install a flushing plate at the collector to replace a precision stopcock (e.g., an electro-hydraulic servo valve).
Note: Before installation, ensure all piping is properly sized and securely connected to prevent leaks.
Purpose of Flushing
Removes residual contaminants (such as metal shavings and fiber compounds) from the system to prevent initial operational problems.
Filter Installation Requirements
- Select a filter with a mesh size of no more than 200 to ensure a stable flow rate in the oil pump suction line.
- Install an air filter on top of the oil tank to prevent external dust from contaminating the lubricating oil. Replace the filter element regularly.
Usage Specifications
- Lubricating oil must be clean and free of impurities to avoid clogging lubrication points.
- Avoid overlubrication: Excessive lubricant will attract contaminants and increase wear.
Regular inspections and maintenance
Maintain sufficient oil in the central lubrication system and ensure that the lubricant used is clean and has no impurities, to ensure that all lubricating positions have enough lubrication supply. If the oil pipe is blocked or leaked, it should be replaced or repaired immediately.
Daily Inspection Items
- Check the oil tank for a reasonable oil level and the lubrication hoses for unobstructed access and undamaged operation.
- Observe all lubrication points for adequate oil supply and refill promptly.
- Confirm that the movable platen guide rails and four-column surfaces are clean and free of wear.
Regular Inspection Items
- Weekly: Check the oil pipe joints for leaks and tighten any loose parts.
- Quarterly: Clean the oil filter and analyze the oil contamination level; inspect the hydraulic cylinder rod for surface damage.
- Semi-annual: Thoroughly inspect the motor and oil pump couplings and relubricate.
Key Inspection Items
- Moving Part Wear: Check hinges, guide rails, and other areas for abnormal wear or iron powder leakage.
- Lubrication Effectiveness: Manually test the distribution valve for proper ejection and resetting, and confirm that the pipes are free of cracks.
Haichen injection molding machine
We are Haichen, a Chinese injection molding machine manufacturer for more than 10 years.
We will remind and instruct our customers how to clean the lubrication system of injection molding machines regularly. This can help better maintain machine’s stable running and improve production efficiency.
Through the above five steps of cleaning the lubrication system of injection molding machines, you can effectively clean and maintain the lubrication system of the injection molding machine.
And extending the service life of the equipment and improving production efficiency.
