Dimensional metrology interoperability and standardization in manufacturing systems

a r t i c l e i n f o Keywords: Dimensional metrology Interoperability Standard development STEP DMIS Dimensional metrology is an important part of any manufacturing system. It consists of distinct components and requires a large, diverse, and interconnected knowledge base. How to pass information seamlessly with minimal cost and minimal data loss between different components of a dimensional metrology system is a major issue that concerns software and hardware vendors, standards developers, and customers. This paper focuses on the four main elements of a dimensional metrology system: product definition, measurement process plan definition, measurement process execution, and analysis and reporting of quality data. The activities and software modules that are involved in these elements are discussed. Key issues that cause interoperability problems are identified. These issues are discussed as they relate to the current situation in dimensional metrology standards development. The STEP (ISO 10303) standards are the product of an international effort to achieve interoperability for manufacturing systems. Extending STEP is an appropriate way to solve the interoperability problem within dimensional metrology systems. Further development of STEP standards is proposed so that Geometric Dimensioning and Tolerancing (GD&T) information already available in STEP can be linked with manufacturing feature information, measurement technology, and measurement results. The proposed STEP data model is an attempt to provide a standard that will support automatic measurement process plan generation for in-process on-machine measurement. Some case studies are under way to test the model. Metrology is the science of measurement and its corresponding accuracy, precision and uncertainty. To measure is to ascertain a numerical value, in terms of some physical unit, to a quantity, quality, magnitude or dimension. To inspect is to determine compliance to a specification (e.g. tolerance) by measuring, gauging, or other means of examination. Often, measurements are performed to verify and inspections are performed to accept. In its most basic form, dimensional metrology can be thought of as the determination of length, angles, and other geometric relationships. In the world of manufacturing, dimensional measurement and dimensional inspection are synonymous with dimensional metrology [1]. Dimensional metrology is an important subject because it is essential for making parts correctly. It is based on complex 3D geometric entities and their relationships. These geome-tries are associated with a large, diverse knowledge base that has many interconnections with entities such as the measurement process, the language of measurement, devices, standards, traceability, and statistics. Geometric Dimensioning …