This paper presents an extended approach to Impact Assessment (IA) within European Union funded large-scale projects within the manufacturing domain, which may offer value to other research projects and SME organisations seeking to develop detailed organizational reporting. It details the six-phase process that forms the framework for this extended approach, demonstrating how project Outcome Indictors and impact assessment criterion can be aligned through an extensive review and integration of existing impact domains, objectives, measures and evidence sources with project documentation to provide the detailed individual impact assessment criteria for this extended IA approach. It also reports on the application of the approach in the EC-funded digital manufacturing project, European Connected Factory Platform for Agile Manufacturing (EFPF), finding that 24 of the 27 IA criteria were met or exceed, suggesting that the project made an important contribution to the EU Industry4.0 ecosystem through furthering the key priorities of Industrial Leadership, Data Integration, Uptake of New Technologies, Open Science, the Circulation of Knowledge, and a minor contribution to Climate Change Mitigation.