The outer casing of the machine head is generally fixed on the fuselage by bolts. The mold inside the machine head contains a core holder, and then the nut is fixed to the inlet port of the machine head, and the inside of the core seat is also mounted. The core, and the core and the core holder have holes in the center for their function to pass through the core. Depending on the type of pressurization method, the extrusion process can be divided into continuous extrusion and intermittent extrusion. The equipment used in the former is a screw extruder, and the latter is a ram extruder. In this case, the screw extruder can be roughly classified into a single screw extruder and a multi-screw extruder by the number of screws.
The working mechanism of the screw extruder relies on the pressure and shearing force generated by the rotation of the screw, so that the material can be fully plasticized and uniformly mixed, and formed by die molding; therefore, sometimes an extruder can be used simultaneously. A series of processes such as mixing, plasticizing and molding for continuous production. In addition, the working mechanism of the ram extruder mainly relies on the plunger pressure to first extrude the previously plasticized material from the die to achieve the forming effect. After the material in the material cylinder is extruded, the plunger will be returned. After adding a new round of plasticized material, the next round of operation will be carried out. This production process is discontinuous production, and the material can not be fully stirred. As well as mixing, in addition, the production needs to be pre-plasticized. Therefore, this method is usually not used frequently in actual production, and can only be applied to plastics with very poor fluidity or very high viscosity, just like nitrocellulose plastic. Molding of plastic products.