STEP-NC is the result of a ten-year international effort to replace the RS274D (ISO 6983) G and M code standard with a modern associative language. The new standard connects CAD design data to CAM process data so that smart applications can understand both the design requirements for a part and the manufacturing solutions developed to make that part. STEP-NC builds on a previous ten-year effort to develop the STEP standard for CAD to CAD and CAD to CAM data exchange, and uses the modern geometric constructs in that standard to specify device independent tool paths, and CAM independent volume removal features. This paper reviews a series of demonstrations carried out to test and validate the STEP-NC standard. These demonstrations were an international collaboration between industry, academia and research agencies. Each demonstration focused on testing and extending the STEP-NC data model for a different application.