17 Preparation Tips Before Operating Twin Screw Extruder

Preparation before Operating Twin Screw Extruder

Do you know what should be paid attention to before you start the twin screw extruder? Good preparation can get high-efficiency work. Below are 17 tips that may be helpful for your operation.

Co-rotating twin screw extruder

1. Check whether the electrical wiring of Twin Screw Extruder is accurate and whether there is looseness.

2. Use a megger to measure the motor and the insulation resistance of the cast aluminium (cast copper, cast iron) heaters shall not be less than 0.5M.

3. Check whether the detecting elements such as thermocouples and melt sensors are well installed.

4. Start the lubricating oil pump, adjust the bypass relief valve, observe the pressure of the oil pressure gauge, control the oil pressure at 0.1~0.2MPa, and check whether the oil lubrication pipeline is smooth and whether there is leakage.

5. Start the water pump of the soft water circulation system, check the joints of each pipeline, whether the pipelines any leaking, check whether the needle valve can be opened and closed, and check whether the solenoid valve can work normally;

6. Check that all upper and lower water pipes, oil pipes and vacuum pipes should be unobstructed without leakage, and each control valve should be adjusted flexibly.

7. Check whether all of the anchor bolts of the whole line are tightened well. Confirm whether the combination configuration of the host screw and barrel is suitable for the formula to be extruded. If it is obviously not suitable, it should be recombined and adjusted. Under normal circumstances, the user should carry out the specified operation on the agreed material according to the screw machine combination recommended by the manufacturer, and contact the manufacturer in advance when changing materials and operations.

8. Confirm whether the combined configuration of the screw and barrel of the co-rotating twin screw extruder is suitable for the formula to be extruded. If it is obviously not suitable, it should be recombined and adjusted. Under normal circumstances, the end user should designate the agreed materials according to the co-rotating twin screw extruder combination recommended by the manufacturer and should contact the manufacturer in advance when changing materials and operations.

For the assembled screws of the co-rotating twin-screw extruder, it is necessary to carefully check whether the combined configuration sequence and number of each element are correct. In particular, check whether the threads at the junction of adjacent screw elements are aligned, whether the kneading block is aligned with the screw elements, whether the staggering angle of the kneading block is correct, whether the screw head is tightened well, and then put into the barrel.

9. After the host of the co-rotating twin-screw extruder is heated to the specified temperature and kept for 30 minutes, press the twin-screw to turn to manual cranking normally. There should be no interference or abnormal noise between the two screws and the barrel and between two screws during the rotation. The movement should be brisk and flexible. If there is an exception (such as caused by 8 mentioned that the screw elements are not installed properly), the screw should be pulled out and reassembled before operation.

10. Check the rotation direction of the Main motor and the feeding motor, facing the discharge head of the main host machine, if the screw element is clockwise, the screw shaft rotates clockwise. Check the operation of each feeder according to the matching requirements of the formula.

11. Clean up the storage hoppers. After confirming that there is no any foreign matter, fill in the storage hopper with raw materials and start the automatic feeding machine. After the material in the hopper reaches the predetermined material level, the load-feeding machine will automatically stop feeding. All kinds of metering and dosing devices should be calibrated on-site according to the process formula requirements, the feeding curve of each feeding device should be given, and the commissioning plan should be agreed upon.

12. For operations that require a vacuum exhaust, add clean tap water to the specified water level in the condensing tank, close the vacuum pipeline and the valves of the condensing tank, and check whether the sealing ring of the exhaust chamber is in good condition.

13. The co-rotating twin-screw extruder head can be equipped with or without a filter screen (generally, it is assembled without a filter screen when leaving the factory). If the process requires a filter screen (net), you can prepare your own filter screen. For a co-rotating twin-screw extruder equipped with an automatic screen changer, please refer to the manual of the automatic screen changer for inspection.

14. The cooling method of the main host of the co-rotating twin-screw extruders is divided into two types: air cooling or soft water cooling. For the air cooling type, check whether the fan is running normally and whether there is any abnormality. For the water-cooled type, there is generally a matching soft water circulating cooling system. Before use, the boiler should be filled with soft water to the specified level in the water tank. When the system is used for the first time, add an appropriate amount of soft water to the normal level after the system is working (because a small amount of water may remain in the pipeline and cooler).

15. For the co-rotating twin-screw extruder with water-cooling strands pelletizing system, also need to check whether the dryer and pelletizer whether can work normally. Before starting the pelletizer, you need to open the pelletizer cover and clean the moving knife and rubber roller to avoid particle residues. Check the wear of the moving knife blade and adjust the gap between the moving knife and the fixed knife. For the co-rotating twin-screw extruder with a water-ring or underwater pelletizing system, the centrifugal dehydrator must be cleaned before running.

16. Clean the vibrating screen silo. Make sure that there are no particles remaining.

17. Only after the above items are carefully and comprehensively checked and confirmed to be correct, the co-rotating twin-screw extruder can reach the conditions to start running.

About US

Nanjing Granuwel Machinery CO., LTD is specializing in the R&D design and manufacture of high polymer extruders, our team of top-level extrusion professionals provides the right extruder for your exact application.

We possess the excellent capability of innovation and product development and desire to provide the best products for our customers through the improvement of equipment structure and reduction of equipment energy consumption through our practical experiences and technical innovation. 

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