Frequent Maintenance of Dual Screw Extruders

In order to produce high-quality products, the dual-screw extruder must be operated strictly in accordance with the operating procedures, and at the same time, the extruder unit must be regularly maintained and maintained.

1. Preparations before starting the dual-screw extruder

For the meshing co-rotating dual-screw extruder, check whether the screw combination is correct before starting the machine. After the screw is installed, slowly turn the screw to make the two screws rotate. If it is easy, it means that the combination is correct.

For the intermeshing early dual-screw extruder, be careful not to mistake the position of the two screws when loading the screws. If the material is piled up at the feeding port and is not conveyed forward after the drive is started, the screw head will push against the machine head and the current will increase. If such a situation occurs, stop immediately, remove the machine head, and reload it in the correct position. .

Before starting the machine, check whether the circuit wiring of each part of the machine is correct; whether the cooling system of the barrel screw is normal and smooth; whether the driving system is normal, whether the lubricating oil level is normal, and whether the oil circuit is smooth; whether the metering feeding and exhaust systems are normal; Whether the connecting bolts are tightened, etc.

Before starting the machine, the part of the extruder that needs to be heated should be heated, and the cooling medium should be introduced into the bottom of the hopper and the cooling part of the screw for cooling. When the set temperature is reached, it should be kept for 10 minutes to make the temperature of the screw and barrel uniform.

2. Points for attention when the dual-screw extruder starts and stops

For granular materials, metering should be used to prevent overloading; for powders, overflow feeding can be used, and pay close attention to whether overloading. When driving, add a small amount of material first, and keep the feeding balance. At this time, pay close attention to the pointer of the torque meter. The rotation speed of the main screw should be rotated at a low speed. When the material is extruded from the die and drawn into the traction equipment, the screw speed is slowly increased, and then the feeding amount is increased until the set value is reached.

Stop feeding before stopping, and the screw of the main engine runs at low speed to discharge the material in the screw cleanly. For the counter-rotating twin-screw, when there is no material discharge from the standby head, remove the head, pull out the screw, clean the screw, head and barrel while it is hot, and then assemble and reset for the next drive.

If cleaning material is used, it is not necessary to pull out the screw of the double-screw extruder for cleaning. For the co-rotating twin-screw, if the screw needs to be reassembled for the next extrusion, the components of the screw must be removed while hot, thoroughly cleaned, and then reassembled according to the new screw configuration. The inner hole of the barrel and the head should also be cleaned.

When cleaning the machine head or screw elements, steel knives, copper brushes and paraffin, gauze, etc. should be used.

3. Repair and maintenance of dual-screw extruder

Regular maintenance should be carried out according to the instructions attached to the extruder when it leaves the factory.

Maintenance and maintenance should also be carried out in ordinary times. If the empty car is not allowed to run, so as not to wear the screw and barrel; if the operation is not normal, it should be stopped immediately for inspection and repair; strictly prevent metal or other debris from falling into the hopper.

If the pressure sensor is installed at the machine head, it should be carefully assembled and disassembled, and the accumulated material on the diaphragm of the sensing part should not be hit or scraped with hard objects, and a protective cover should be worn when not in use.