These molds are key for metal - plastic composite molding. With designs like half - slides and hot - runner temperature control, they seamlessly integrate metal inserts (tolerance ±0.02mm) and plastic layers, avoiding defects like weld lines. For example, automotive door handle molds overmold TPE on aluminum alloy, with a 45–60 - second cycle, boosting efficiency.

The core lies in material compatibility and thermal management. For substrates like aluminum alloy and stainless steel, positioning slots and vents prevent displacement and gas trapping. Partitioned temperature control rapidly solidifies the plastic melt on metal surfaces, forming an 8–12MPa composite layer. Suitable for gearbox seals and throttle bodies, it withstands - 40℃ to 150℃.

Driven by automotive lightweighting, these molds reduce weight via “plastic - for - steel”. For instance, steel - plastic composite bearing seats cut weight by 40% while retaining load capacity. They also enable integrated functions, like metal brackets overmolded with conductive plastic for structure and electromagnetic shielding, simplifying assembly. They fuel the manufacturing upgrade of new energy vehicle battery packs and motor housings.