Thermoplastic injection molding refers to the process of manufacturing products using thermoplastic plastics as the raw material, utilizing the injection molding process.
Repeated Softening and Hardening: Thermoplastics melt into a fluid state when heated and solidify into a fixed shape upon cooling. This process constitutes a physical change that can be repeated multiple times, thereby facilitating recycling and reuse.
In typical thermoplastics, the molecular weight of the polymers can range from hundreds of thousands to several millions, and the length of the macromolecular chains can reach 10⁻³ mm. These macromolecules may be linear-such as LLDPE and HDPE-or branched, such as LDPE. The macromolecules become entangled with one another, arranging themselves in either a disordered or relatively ordered manner to form a "condensed-state structure."
When the macromolecules are arranged in a completely disordered fashion, the material is classified as an amorphous thermoplastic; examples include PVC, PC, and PMMA. These materials are characterized by good transparency, relatively low mechanical strength, and high flexibility. Conversely, materials in which some macromolecules-or segments thereof-are arranged in a uniform, ordered structure are classified as crystalline thermoplastics; examples include LLDPE, POM, and nylon. These materials are characterized by relatively poor transparency, high mechanical strength, and lower flexibility.
High Molding Efficiency and Suitability for Mass Production: The injection molding cycle is short (typically 30–60 seconds), automation is easily implemented, and the unit cost of production is low.
