1. Injection molding process: First, add solid thermoplastic composite pellets from the hopper to the injection molding machine. In the screw extrusion section of the injection molding machine, the reinforced pellets are heated, plasticized and melted; then, under high pressure, the melt is pushed into the mold cavity of the molding mold, and after cooling and shaping, it is a product after demolding.
2. Compression molding process:
A: Compression molding process of pellets: The compression molding of long fiber reinforced thermoplastic composite pellets is very similar to the compression molding process of thermosetting composite materials. The process is: according to the size and quality of the molded product, the long fiber reinforced pellets are weighed and directly added to the preheated molding mold, and the mold is heated until the polymer matrix is completely melted. Then, the mold is closed and a certain molding pressure is applied to the mold to fill the mold cavity with the molten material.
B: Stamping and flow molding process: First, the glass fiber mat reinforced thermoplastic composite sheet is sent to the heating furnace for preheating. The preheating temperature is generally 25-50 degrees higher than the melting point or softening point of the thermoplastic matrix resin. Then, the softened and fluffy material after preheating is taken out from the preheating furnace and quickly placed in the stamping mold, and the mold is quickly closed and pressurized; under the action of pressure, the softened and molten material flows in the mold to fill the mold cavity.
3. Direct molding process: The characteristic of this technology is to combine the preparation technology of long fiber thermoplastic composite materials with the product molding technology. In the first step, two extruders are used, one extrudes a molten mixture of thermoplastic plastics and other auxiliary materials, and then mixes and impregnates with glass fiber with the second extruder to form a resin/glass fiber mixed blank; the second step is to manually or mechanically send the blank directly into the preheated mold and mold it into a composite material under a certain pressure.
