An IEC 61499 Function Block based Approach for CNC Machining Operations

In order to create an adaptive and interoperable CNC control system to explore the full functionality of CNC machine tools and to surpass the shortcomings and restrictions of the current CNC control standard using G-codes, an IEC 61499 function block based control system model has been developed. Basic machining operations are identified and classified as machining features, which are wrapped into Machining Feature Function Blocks (MF-FBs) with algorithms. For the machining of a part, the required MF-FBs are selected and combined into a Composite Function Block, comprising the correct control instructions for machining the part. The event-driven nature of these function blocks enables the run-time selection of appropriate algorithms and control of their correct behavior and dynamic execution, supporting the system’s ability to act in response to actual conditions and manufacturing requirements. Being truly adaptive makes it possible that different available machine tools be selected to machine a part with the appropriate control code generated at runtime. This eliminates the tedious CNC programming effort, and therefore no predefined, machine-specific control code has to be generated in advance. The use of generic function blocks for encapsulation of machining know-how in algorithms makes machines and CNC systems independent and therefore portable, reusable and interoperable