Molded Interconnect Devices (MIDs) are 3D plastic parts that combine mechanical structure and functional circuits in the same component. After injection molding a thermoplastic substrate, conductive traces are selectively added using methods such as laser-direct structuring (LDS) or two-shot molding, then metallization (copper, nickel, gold, etc.). This allows traces to run over curved surfaces, around corners, or across complex shapes, reducing assembly steps, saving space & weight, and improving integration. Commonly used in automotive electronics (antennas, sensors, lighting), medical devices, and consumer electronics where space, reliability, and design flexibility matter.