Daily Maintenance at Shift Start
Plastic blow molding machines require consistent daily maintenance to ensure operational stability and product quality. At the start of each shift, add lubricating oil to every moving component. Before operation, check whether lubrication at each designated lubrication point is sufficient. Verify all moving parts are functioning properly and that each limit switch and fastener shows no signs of loosening.
Check the hydraulic oil level - the oil tank surface should remain above the oil gauge reference line. Clean the oil filter screen near the electromagnetic directional valve. These foundational checks prevent the majority of common operational issues before they can develop into production-disrupting problems.
Weekly Maintenance Schedule
- Lubrication System: Check all lubrication points and refill grease cups. Clean filters for mechanical lubricating pumps. Tighten all pipe joints that may be loose.
- Hydraulic System: Inspect hydraulic oil pipes and joints for leaks. Tighten any loose electrical connectors.
- Pneumatic System: Drain water from air filters daily in high-humidity conditions. Verify proper pneumatic valve operation.
- Safety Devices: Test all limit switches and emergency stop functions. Check safety door interlock mechanisms.
- Screw and Barrel: Monitor screw rotation sound for any abnormal noise that might indicate wear or material issues.
Monthly Maintenance
- Check electrical control cabinet interior for cleanliness; remove accumulated dust
- Inspect motor operation and verify motor cooling fan functionality
- Check all belts, chains, and gears for proper tension and wear patterns
- Verify heating system operation including calibration of all temperature controllers
- Test cooling water system flow rates and inspect for scale buildup
- Clean all heat exchanger surfaces for optimal heat dissipation
Hydraulic System Care
The hydraulic system is critical to blow molding machine operation. Key maintenance includes checking the hydraulic oil temperature, which should be maintained between 35 and 55 degrees Celsius under normal conditions. High oil temperatures accelerate oil degradation and seal deterioration. Regularly inspect hydraulic pump operating pressure and listen for abnormal noise. Standard operating pressure should remain within the range indicated on the pressure gauge, typically 140 to 175 kg per square centimeter. Verify that system pressure matches equipment requirements and adjust if necessary.
Heating System Maintenance
Inspect all heating rings for proper tightness. Due to thermal expansion during operation, heating rings may become loose and require periodic retightening. Check the ammeter reading for each heating zone to verify normal current flow. Abnormal current readings may indicate damaged or failing heating elements that need replacement. Verify thermocouple contact with temperature measurement points. Loose thermocouples cause inaccurate temperature readings that directly affect product quality. Clean carbonized material residue from heating zones regularly.
Long-Term Shutdown Preservation
When the blow molding machine will be idle for extended periods, comprehensive preservation steps are necessary. Clean all material residues from the hopper, barrel, and screw. Apply anti-rust treatment to all exposed metal surfaces and mold components. Drain and clean the cooling water system to prevent scale and algae growth. Protect electrical components from moisture by placing desiccant packets in control cabinets. Cover the machine with protective sheeting in a dry, well-ventilated environment. Before restarting after long shutdown, perform complete system checks and run the machine empty for a period before resuming production.
