This document specifies an OPC UA Information Model for the representation of an additive manufacturing machine (“AM machine”), as defined by ISO/ASTM 52900:2021 (3.1.4). It supports but is not limited to all industrial AM process categories listed by ISO/ASTM 52900:2021: Binder Jetting, Directed Energy Deposition, Material Extrusion, Material Jetting, Powder Bed Fusion, Sheet Lamination, Vat Photopolymerization. OPC UA for Additive Manufacturing aims at straightforward integration of an AM machine into higher level IT systems. The scope is to create a common interface that enables identification, monitoring and controlling* AM machines of different technologies, manufacturers and model series (*covered in later versions). Peripheral systems of the AM process chain (e.g. post processings) are not considered in this first version of the specification. This OPC UA for Additive Manufacturing interface allows an exchange of information between an AM machine and software systems like MES, ERP, SCADA or data analytics systems.