The plasticizing device of injection moulding machine is generally
equipped with an integral rotating mechanism. When assembling and
disassembling the screw nozzle, screw and barrel of the injection
moulding machine, the positioning screw of the injection moulding
base should be loosened first to deflect it from the original
position at a certain angle, so that the barrel axis of the
injection moulding base can avoid the axis of the clamping device,
so as to facilitate the disassembly, assembly and maintenance of
the screw and barrel of the injection moulding machine.
A. Removal of screw nozzle of injection moulding machine
If there is any residual material in the barrel, it should be
heated to the plasticizing temperature first, and the high thermal
stability polyolefin resin or special cleaning material for the
barrel should be used to fully clean the barrel at high speed, and
the residual melt can be discharged as far as possible before the
disassembly work can be carried out. Since the residual material in
the nozzle part can not be discharged completely, the nozzle or the
head of the barrel should be heated before the nozzle is
disassembled. After the injection machine screw nozzle is heated
up, the special hammer is used to knock it loose. The bolt should
not be loosened completely. When it is loosened to 2/3, it is
lightly knocked. After the internal gas is released, the nozzle is
unloaded. Cleaning the screw nozzle of injection moulding machine
should be carried out at high temperature while it is hot, so as to
remove the residual melt from the nozzle hole in the runner. The
method is to inject demoulding agent from the nozzle to the inside,
i. e. to drip the demoulding agent from the side of the nozzle
thread to the material and the inner wall surface, so that the
material and the inner wall are separated, and the material is
taken out from the nozzle.
B. Maintenance and repair of screw nozzle of injection moulding
machine
If the contact part between nozzle and positioning sleeve of die
occurs unilateral contact or bad contact in production, the
spherical R part of front end will be deformed, forming a groove
for melt escape, resulting in overflow at nozzle, and the caliber
part will also be deformed. Therefore, overflow should be checked
and repaired in time. C. The threaded parts of the nozzle should be
inspected regularly and the sealing surface on the side of the
barrel should be replaced in time if serious wear or corrosion is
found. D. Check the internal passage of screw nozzle of injection
moulding machine. The surface quality of the melt strip can be
observed by air injection moulding, and the residual melt
discharged from the nozzle can more accurately reproduce the runner
condition in the nozzle. The residual amount and temperature
distribution of the melt in the nozzle can be analyzed.
