Plate Vulcanizer

1. Loading and Molding Stage: Pre-weighed compound or preformed blank is precisely placed into the cavity of the preheated lower mold. The equipment is then activated to close the upper and lower molds. The hydraulic system applies initial preload to ensure stable mold closure. Simultaneously, upper and lower heating plates—powered by electric heating elements or steam—continuously heat the mold, rapidly raising the compound to its vulcanization temperature range (typically 140°C–200°C depending on rubber type; e.g., natural rubber around 140–160°C, EPDM rubber up to 160–180°C). During this stage, the rubber softens, its viscosity decreases, and its flowability increases, preparing it to fill the mold cavity.

2. Pressure Vulcanization Stage: Once the mold temperature reaches and stabilizes at the rubber's optimal vulcanization temperature, the hydraulic system rapidly increases pressure to the set working pressure (typically 10–25 MPa based on product requirements, or expressed in equipment tonnage like 100 tons or 500 tons). Under the combined effects of high temperature and pressure, the rubber compound is compressed and fills the entire mold cavity, forcing air and volatiles generated during vulcanization to escape through the mold's venting channels. Simultaneously, the three critical factors—temperature, pressure, and time—are synergistically controlled according to the preset vulcanization process curve. This facilitates the formation of sulfur bridges between rubber molecular chains, triggering cross-linking reactions (vulcanization). This process ensures the product achieves its designed physical properties while effectively preventing defects such as short shots, bubbles, and surface defects, guaranteeing uniformity and consistency in product performance.

3. Venting and Demolding Stage: For complex or high-precision products, multiple venting operations (de-gassing) may be performed during the initial vulcanization phase. This involves briefly releasing pressure to slightly open the mold, thoroughly expelling trapped air from the cavity before reapplying pressure. This significantly enhances product density. After completing the pressure-holding vulcanization, the system automatically releases pressure and opens the mold. Subsequently, the ejection device or demolding mechanism pushes the formed rubber product out of the mold. The final product exhibits high dimensional accuracy, a smooth surface finish, a dense structure, and stable physical and mechanical properties, meeting the application requirements for high-performance rubber products across various industries.