Injection molding machine plasticizing unit four components technical requirements.
Nozzle
Straight-through nozzle is a widely used nozzle. Its feature is that the spherical surface of the nozzle directly contacts with the main cast sphere of the mold. The arc radius and flow path of the nozzle are smaller than the mold. During injection, the high-pressure melt passes directly through the runner system of the mold. Filled into the mold cavity, speed, pressure loss, manufacturing and installation are more convenient.
The locking nozzle is mainly used to solve the flow problem of the straight-through nozzle and is suitable for the processing of low-viscosity polymer (such as PA). During the pre-molding, the nozzle flow path can be closed to prevent the melt flow phenomenon, and when it is injected, Under the effect of injection pressure, the melt is injected into the mold cavity.
2. Injection cylinder
The working principle is: When the injection cylinder enters the oil, the piston drives the piston rod and the bearing placed in the thrust seat to push the screw forward or backward. Through the nut of the piston rod head, the axial position of the two parallel piston rods can be The axial position of the injection screw is adjusted synchronously.
When the thrust seat is injected, the thrust seat pushes the screw through the thrust shaft to perform injection; during pre-molding, the oil shaft is driven by the oil motor to drive the screw to rotate to achieve pre-molding.
3. Block shift cylinder
When the cylinder is moved into the oil, the injection seat can be moved forward or backward, and the injection nozzle can be in close contact with the main pouring circular surface of the mold to generate the pressure of the injection seat that can seal the melt.
4. Accuracy requirements for injection parts
After the nozzle is assembled, the integral injection part is placed on the frame, and the nozzle must be tightly engaged with the main casting sleeve to prevent flash.
It is required that the centerline of the injection part should be concentric with the centerline of its part; in order to ensure the accuracy of the injection screw and the inner hole of the barrel, the parallelism of the two injection cylinder holes and the center hole of the barrel must be guaranteed to be symmetrical with the centerline. degree.
For horizontal machines, the parallelism of the two guide holes of the shift cylinder and the symmetry of its center must also be guaranteed.