Basic development of data sharing CNC system (Case study on high accuracy machining of characteristic lines)

In this study, machining problems that can be solved by a numerical controller are considered, and a solution method is proposed. Regarding the data flow of machining process chains, product shape data created by computer-aided design (CAD) are converted into point sequence data by computer-aided manufacturing (CAM) to create a machining program in the machining process chain. Computer numerical control (CNC) faithfully interpolates a dedicated CNC program (ISO code) indicating a tool path and processing conditions, called G code, for machining a workpiece. However, there are no design shape data in the machining process. As the result, accurate measurement and correction with additional processing are required to obtain a high-precision product shape. In this study, as a mechanism that enables information flow belonging to CAD and CAM to be shared without losing it until CNC program execution, the implementation of an integrated CNC system with a shared database is addressed. Information in this database is described according to a predetermined format as data models. The data model that is the basis of information sharing and its practical use are described. Forming characteristic lines on a die were applied for confirmation of the effectiveness of the mechanism using data model. It was confirmed that actual machining realized high machining accuracy compared to the conventional technology.