Detailed introduction

15

2022

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09

Analysis of Partial Causes of Breaking of Barrel Screw


  barrel screwFracture part of the cause analysis

  

机筒螺杆


The fracture temperature of the barrel screw is also related, but rarely, almost all the barrel screw itself material toughness is poor, or used, refurbished screw! The raw materials are rough, such as the raw materials added with GF [glass fiber] that kind of raw materials cost screws and machines! This raw material has poor fluidity and requires fast sintering speed! The master is not good, the light fire arrow, the reverse ring is broken, and the heavy screw is broken in many sections! Screw fracture can be prevented. GF should be added when using raw materials. If the machine is shut down for more than 3 minutes, the material in the material pipe should be cleaned up. PP viscosity is recommended to clean the screw to prevent the raw materials from being wrapped in the screw and the fire arrow from decomposing.

When the barrel screw is cleaned, the speed is reduced to fully melt the raw material in the hot rotation. The cleaning screw of the needle point mold is good, the glue channel is pasted on the static template, and the hot material is used for startup production! When the work order is completely stopped, it is enough to do a good job of mass-produced products. When the work order is stopped, clean the screw immediately to discharge all the residual raw materials of the screw. When using PP or cleaningbarrel screwof raw materials. Process problems, back pressure and screw fracture are also related! Back pressure is too large, when feeding, the screw force increases, will also make the screw fracture! The injection end cannot be zero, especially the rocket head is easily damaged by pressing and storing the injection with a high-speed injection machine! The injection residue shall be controlled. Remember, the key is to set the hold time to zero during manual injection to prevent the glue from being zero at the end of the injection! [Key] The molding temperature should be well controlled. When starting the machine, pay attention to the loose back in injection molding, because under the condition of not loose back, the fire arrow has raw material packaging. If it is directly cleaned or injected, it will directly cause the fire arrow to break and the reverse ring to break. Remember to loosen the back successively in injection molding to separate the raw materials of the fire arrow and the fire arrow!! The key is to remember that no matter what raw materials are used, production must be stopped, and the remaining raw materials must be drained to prepare for the next production! In the process of plastic melting and plasticizing, the molten material continues to move to the front end of the cylinder (the amount of room), and more and more, gradually forming the pressure to push the screw backward. In order to prevent the screw from retreating too fast and ensure uniform fusion, it is necessary to provide pressure in the opposite direction to the barrel screw, which is called back pressure. Back pressure, also known as plasticizing pressure, is controlled by adjusting the oil return throttle valve of the injection cylinder. The pre-plastic screw injection molding machine is equipped with a back pressure valve after the injection cylinder. When the screw rotates backward, the oil discharge speed of the injection cylinder is adjusted to maintain a certain pressure of the cylinder. The screw speed (resistance) of the entire motor is controlled by an AC servo valve.