Plastic granulator failure, four failures and solutions

2021-06-03

During the long-term use of the plastic granulator, failures will inevitably occur. For the causes and repair schemes of various shortcomings, this article puts forward some suggestions for reference.


The common faults of Plastic pelletizing machine mainly include the following categories.

1. The main motor torque is too high
2. The main engine motor torque is too low
3. The friction clutch fails
4. The granulator screw is faulty.


The cause of the failure of the primary motor torque is too high:

Failure of the oil lubrication system may cause poor contact between the main motor and the gearbox's input and output shafts. The vibration of the engine and clutch can damage the main motor bearings and cause excessive torque. At the same time, an unreasonable load of the feed material or inadequate melting of the material will also cause the main motor torque to be too high.
Solution:
① Regularly check and clean the lubricating oil system, measure the main motor bearings with a vibration measuring instrument and an infrared measuring instrument, and make a trend chart. When the trend value is exceeded, measure whether the primary motor's current idling value or power value exceeds the specified value and judge whether the bearing should be replaced. 
②Regularly check the contact between the primary motor's output shaft and the gearbox's input shaft. The connection should be checked after the first start-up or the replacement of the bearing for three months.
③Electrical test checks to determine the cause of the rotor imbalance. The clutch shall be subjected to a vibration speed test. When it exceeds the specified value, the dynamic balance must be readjusted.
④ Regularly check the heating and cooling system of the cylinder to ensure that the material is heated and melted evenly. When the extruder is switched on, if the power curve and melt pressure curve of the main motor increase instantaneously, the feed rate of the feed system is instantaneously too large, and the feed rate should be reduced.

Gear failure of plastic pellet mill


The main motor torque is too low and the cause of the fault:

The supply system failure caused the twin-screw to run idly, and the main motor torque was too low.

Solution:
Check whether the additive system or the feeding system is faulty, and clean the blockage of the plastic pellet machine.


Plastic granulator Causes of friction clutch failure:

The starting voltage of the main motor is too low; the friction clutch instrument wind pressure is too high, the friction clutch speed difference is too large

Solution:
①When the main motor starts, avoid power peaks and reduce the supply load. The minimum restart interval is 30 minutes
② When starting the main motor more than two times in summer, the interval time should be extended, or forced cooling with a fan.
③ Blow with instrument wind, and wipe the dust on the surface of friction plate and friction plate with a rag. Confirm whether the air pressure value can match the friction disc with the friction plate.


Reasons for Failure of the screw process section of the Plastic granulator:

The melt pressure before and after the throttle valve is too high, the melt pressure of the machine head is too high, the melt pressure before and after the mesh exchanger is too large, the driving valve rotation failure, etc.

Solution:
When the extruder is turned on, when the power curve of the main motor and the melt pressure curve increase, the supply volume of the supply system is too large, and the supply volume should be reduced.
For more industry information, follow packer.