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Injection molding machine screw fracture reason

Update:01 Nov 2019
Summary:

The screw fracture temperature also has a relationship, […]

The screw fracture temperature also has a relationship, but it is rare. Almost all of the screw itself has poor toughness, or it has been used for a long time, and the screw is refurbished!

Raw materials are rough, such as raw materials added with GF [glass fiber] which is the most expensive screw and machine! This material has poor fluidity and requires a fast rate of fire! Mastery is not good, the light rocket head, and the reverse ring rupture, the heavy broken screw is multi-section!

Screw breakage can be prevented. In the use of raw materials to add GF, if the shutdown is more than 3 minutes, the raw materials in the cleaning tube should be cleaned. It is better to use PP with higher viscosity and clean the screw to prevent the decomposition of the raw material to wrap the screw and the rocket head. When cleaning, the rotation speed is reduced, so that the raw material is fully melted under the heating rotation. The cleaning screw is best for the needle-point mold, and the rubber passage is prevented from being stuck on the static template, and the hot material is used for starting production!

When the work order is completely shut down, work is done, the mass production product is enough. Immediately after the shutdown, the screw is cleaned, the residual raw materials of the screw are all discharged, and then the PP or the raw material of the cleaning screw is used.
Process problems, back pressure and screw breaks are also related! The back pressure is too high. When feeding, the force after the screw increases, and the screw can also be broken!

The end of the injection glue can't be zero, especially with a high-speed injection machine, it is easy to damage the rocket head! The amount of shots to be shot must be controlled. Remember, the most critical, manual injection must adjust the holding time to zero, to prevent the end of the injection glue is zero!

The molding temperature should be controlled. At the time of starting up, pay attention to the retreat and then shoot out, because there is a raw material package at the rocket head when there is no retreat. If the material is directly washed or shot, it can directly cause the rocket to break, and the reverse ring is broken. Remember to retreat again. Shoot out, separate the rocket head material from the rocket head!