A set of heterogeneous entities is typically used to perform the various operations involved in manufacturing. To reason about these entities requires that a software representation be developed that reflects the ability to integrate with other entities and handle the enhanced levels of control functionality that integration should allow. The current software representations of manufacturing entities, MMS and the ESPRIT approach, lack the ability to robustly model a manufacturing entity. This paper presents a modelling methodology for multi-axis manufacturing entities. This model, called open control interface (OCI), provides a mechanism for controlling a multi-axis manufacturing entity from remote entities and programs. Unlike the traditionally used functional decomposition process to model manufacturing entities, the OCI approach encapsulates both physical and functional characteristics of manufacturing entities into modules that form the model. The physical modules make the mapping from the model to th...