The CNC interpreter is an important part of CNC systems. It detects errors in NC programs and translates NC programs into internal commands for the followed CNC tasks. There are many vendor-specific NC programming languages. For each language, a corresponding CNC interpreter must be encapsulated in the CNC system. Thus, a universal CNC interpreter is desired. Besides, the CNC interpreter is desired to be scalable that allows users to define new instructions. In this paper, therefore, a universal and scalable CNC interpreter is presented. The interpretation process contains the grammar analysis part and the synthesis part. The grammar analysis is implemented depending on the grammar specification. Thus, as long as the grammar specification for vendor-specific commands or user-defined commands is constructed and configured, the CNC interpreter can interpret them. The synthesis part maps the output of the grammar analysis to machining functions. Specific operations contained in NC programs are implemented by an integrated operation postprocessor to guarantee positions in machining functions are practical cutter location positions. Moreover, the CNC interpreter is error tolerant for specific errors. There is a simulation module encapsulated in the prototype CNC interpreter so that this interpreter can run independently to pre-test NC programs in addition to implementing the interpretation task for a CNC system.
