How does injection-molded embedded plastic copper mother plates with copper sheets achieve the integrated formation of a plastic insulating base and a conductive copper sheet?
Publish Time: 2025-09-16
In modern electrical and electronic systems, the demand for highly reliable, highly integrated, and miniaturized power transmission components is growing. Injection-molded embedded plastic copper mother plates with copper sheets have emerged as a key solution for connecting and distributing high currents. This technology pre-places a highly conductive copper sheet in a mold before injecting high-temperature molten plastic. This technology achieves an integrated formation of the "metal conductor" and "plastic insulating base." It is widely used in new energy vehicles, charging stations, smart meters, photovoltaic inverters, industrial power modules, and other fields.1. Core Process: Embedded Injection Molding TechnologyThe core of integrated molding lies in the "embedded injection molding" process. This process begins by precisely securing stamped, bent, and surface-treated high-purity electrolytic copper sheets (or copper strips) in predetermined positions within a specialized mold. These copper sheets serve as conductive paths, carrying current. Their shape, thickness, and spacing are customized to meet electrical design requirements. The mold then closes, and high-temperature molten engineering plastic is injected under high pressure into the mold cavity, enveloping the non-conductive areas of the copper sheet. After cooling and solidifying, the plastic forms a strong physical bond with the copper sheet. Finally, the mold is removed to produce an embedded copper motherboard that combines both electrical conductivity and insulation.2. Precise Positioning: Ensuring the Stability of the Copper Sheet During the Injection Molding ProcessThe copper sheet must maintain absolute positional accuracy during the injection molding process; failure to do so will result in short circuits, insulation failure, or assembly difficulties. To this end, the mold is designed with precise positioning pins, clamping structures, or vacuum suction devices to securely hold the copper sheet at predetermined coordinates in three-dimensional space. Some high-end processes also utilize automated robotic arms for copper sheet loading, ensuring repeatable insertion accuracy within ±0.05mm. Furthermore, the edges of the copper sheet are often designed with "anchor grooves" or "undercuts" to allow the plastic to flow into tiny pores during filling, creating a mechanical interlock and further enhancing bond strength.3. Material Synergy: The complementary properties of plastic and copperThe plastic insulating base not only provides structural support but also fulfills multiple functions, including electrical isolation, heat resistance, flame retardancy, and moisture resistance. The selected engineering plastics typically feature high CTI values, UL94 V-0 flame retardancy, and excellent temperature resistance, ensuring no breakdown or carbonization in high-voltage, high-current environments. Furthermore, the plastic's low coefficient of thermal expansion matches the thermal properties of copper, reducing internal stress cracking caused by temperature cycling. The copper sheets undergo surface treatments such as tin plating, silver plating, or silver-over-nickel plating to enhance conductivity, oxidation resistance, and soldering reliability, ensuring long-term, stable electrical connections.4. Sealing and Insulation: Providing Reliable ProtectionDuring the injection molding process, the molten plastic completely encapsulates the sidewalls and bottom of the copper sheet, leaving only the necessary conductive contact surfaces (such as terminals and pads) exposed, creating an "encapsulated" insulation structure. This integrated encapsulation effectively prevents contaminants such as dust, moisture, and salt spray from invading the gaps between the conductors, preventing leakage, short circuits, or electrochemical corrosion. This structure significantly enhances the product's environmental adaptability and service life, particularly in outdoor or high-humidity environments.5. Integrated Design: Simplifies Assembly, Improves ReliabilityTraditional power connections often rely on wiring harnesses, bolts, or discrete terminals, which can lead to high contact resistance, looseness, and large space requirements. Injection-molded embedded copper motherboards, on the other hand, integrate multiple conductive paths, mounting structures, and insulation barriers into a single unit, reducing assembly steps and connection points, thereby lowering the risk of failure. For example, in the battery management system (BMS) of new energy vehicles, a single embedded copper motherboard can simultaneously perform voltage sampling, current transmission, and temperature monitoring, significantly improving system integration and reliability.The injection-molded embedded plastic copper mother plate with copper sheet mold design, automated insert positioning, high-performance material matching, and advanced injection molding processes to achieve high-strength, high-precision, integrated molding of the conductive copper sheet and insulating plastic base. This represents not only an innovation in electrical connection technology but also a model for intelligent manufacturing and high-reliability design. As power electronics systems evolve towards higher efficiency, compactness, and intelligence, this technology will continue to drive electronic and electrical products towards higher performance, longer life, and smaller size.
