Parallel twin screw extruders are the workhorses of many industrial processes, used for a wide range of applications from plastics compounding to food processing. To ensure these machines continue to perform at their best, regular maintenance is crucial. In this article, we will explore the essential aspects of maintaining a parallel twin screw extruder, helping you extend its lifespan, improve product quality, and optimize production efficiency.
Maintenance during operation of parallel twin screw extruder
- Prevent any material contamination by strictly prohibiting debris, especially hard substances like metal and sand, from entering the hopper and barrel.
- When opening the suction chamber cover, take precautions to prevent foreign objects from falling into the barrel.
- Allow the twin-screw extruder to preheat adequately and start the operation after proper heating.
- Begin by gradually increasing the screw speed, ensuring that idling time does not exceed 2 minutes.
- After feeding, increase the feeder rate gradually for optimal operation.
The daily maintenance of main parts of parallel twin screw extruder
Daily maintenance of the main machine
- Change the oil and lubricating oil every 4000 hours.
- If the main motor is a DC motor, inspect the carbon brush monthly, and maintain a record. Replace the carbon brush if needed.
- Purge the electric control cabinet monthly.
- Quarterly, examine the wear of the screw and barrel, and keep detailed records.
- Perform an annual check on the gearbox’s gears, bearings, and oil seals.
- When the machine faces prolonged downtime, apply anti-corrosion and anti-fouling treatment.
Maintenance of parallel twin screw extruder barrel
Maintenance of a parallel twin screw extruder barrel is crucial to ensure its long-term performance and efficiency. Here are some key maintenance knowledge points for the barrel:
- Regular Cleaning: After each production run, thoroughly clean the barrel to remove any residual materials. Cleaning prevents contamination and maintains product quality.
- Inspection for Wear and Damage: Regularly inspect the inner surface of the barrel for signs of wear, damage, or corrosion. If you notice any issues, address them promptly to prevent further damage.
- Barrel Liners: Some barrels have replaceable liners. Check these liners for wear and replace them as needed to maintain the integrity of the barrel.
- Temperature Control: Ensure that the barrel’s heating and cooling systems are functioning correctly. Proper temperature control is essential for consistent product quality.
- Screw and Barrel Alignment: Verify that the screws are correctly aligned with the barrel. Misalignment can cause wear and damage. Adjust as necessary.
- Lubrication: If applicable, lubricate any parts that require it according to the manufacturer’s guidelines.
- Documentation: Maintain detailed records of inspections, maintenance activities, and any issues encountered. This documentation helps track the condition of the barrel over time.
- Manufacturer Guidelines: Always refer to the manufacturer’s specific maintenance instructions for your twin screw extruder model to ensure you’re following the correct procedures.
Overall maintenance of parallel twin-screw extrusion
Here are the main points to focus on when maintaining a parallel twin-screw extruder, excluding those mentioned in the barrel maintenance:
- Fasteners and Lubrication: Regularly inspect and tighten loose screws and fasteners. Maintain proper lubrication in the transmission box, cleaning the oil tank regularly, and changing the oil every 3 months for new machines and every 6 months to a year thereafter. Clean the oil filter and suction pipe monthly.
- Screw Installation: When reinstalling, ensure screws A and B are in their original positions. Test new screws manually before operating at low speed. For long-term storage, take anti-rust and anti-fouling precautions, suspending the screw. For thread block cleaning, use controlled burning.
- Temperature Control: Regularly calibrate the temperature control instrument to check adjustment accuracy and control sensitivity.
- Cooling Water Tank: Use distilled water to prevent scaling in the barrel’s cooling water tank. Monitor water levels and add water as needed. If scaling occurs, replace the cylinder.
- Solenoid Valve: Check solenoid valve functionality and the condition of coils, replacing them as necessary.
- Heating Zone and Relays: Ensure the daily coupler is secure, heating zone relays are functioning, and solenoid valves work correctly. Replace deformed heaters and tighten loose screws.
- Vacuum Tank and Exhaust Chamber: Clean the vacuum tank and exhaust chamber to maintain smooth airflow. Regularly inspect and replace worn sealing rings on the vacuum pump. Address any damage to the output shaft or bearings.
- DC Motor Inspection: For DC motors, regularly check brush wear, contact points, and insulation resistance. Examine connecting wires and components for rust, and implement protective measures as needed.
- Long-Term Storage: Apply anti-rust grease to the screw, machine, and head surfaces when the extruder will be inactive for an extended period. Hang small screws or store them in a wooden box, leveling them with wooden blocks to prevent deformation or damage.
- Cooling Water Pipes: Inspect cooling water pipes for scaling on the inner wall and corrosion on the exterior. Descaling and anti-corrosion measures are crucial for maintenance.
Regular maintenance is the key to a long-lasting and high-performing parallel twin screw extruder. By following a diligent maintenance regimen, you can ensure that your equipment operates at peak efficiency, produces high-quality products, and remains a valuable asset to your industrial processes. Keep in mind that while this article provides general guidelines, always refer to the manufacturer’s specific maintenance instructions for your extruder model to achieve the best results.