The digital twin system enhances productivity in smart factories by facilitating real-time monitoring and control of manufacturing facilities and processes. This study introduces a novel digital twin model, along with its implementation results, for smart factory applications. We implemented a digital twin testbed system for a USB packaging facility and an industrial robot designed for assembly operations, based on this new model. Both applications employed 3D digital models that replicated actual facilities and processes with high fidelity, a novel approach developed to enable interoperability and control through the OPC UA protocol. The system supports the real-time monitoring and management of information pertaining to facilities and processes across multiple devices.