CNC (computer numerical control) systems play an ultimately important role for controlling EDM (electrical discharge machining) machine tools and their machining processes. Till now, existing CNC systems do not offer sufficient openness that supports researchers and engineers to expend its capabilities and functionalities in response to the increasing demands of smart manufacturing; on the other hand, transforming an EDM machine made by small and medium-sized machine tool builders, into a smart manufacturing system has never been an easy job. To address the issues and overcome the difficulties which block the way towards smart manufacturing, this paper proposes an open architecture CNC platform for EDM machine tools. This platform utilizes the state-of-the-art technologies in implementation of the hardware and software without compromising with the constraints of obsolete techniques. For demonstrating the unique capabilities, the generalized unit arc length increment (GUALI) interpolation method and the Digitizer/Player system architecture are adopted. To exhibit the feasibilities of the newly developed platform, three kinds of EDM machine tools are applied associated with advanced functionalities such as machining process adaptive control, applications of machine learning, 6-axis EDM of shrouded turbine blisks etc. In addition, a small-scale smart manufacturing unit for drilling film cooling holes of turbine blades is built up into real production by applying the new CNC system and related software applications. From the practitioner's viewpoint, openness and standardization are the keys that enable the people from academia and industry bringing in their domain knowledge to enrich the smart manufacturing ecosystem.