Open Cnc Machining System Under Integrated Manufacturing Environment

Manufacturing as a pillar industry of national economy is the basis for other sectors of the economy. Integrated manufacturing technology is the current development direction of manufacturing which is based on numerical control technology. Open CNC System currently is the main direction of development for CNC system. The integration of Open CNC system with contemporary integrated manufacturing systems is one of main research topics on contemporary manufacturing.Manufacturing system integration model is set up in accordance with the principle of Increasing Precision with Decreasing Intelligence (IPDI). And the corresponding hardware platform is designed.The model is divided into four levels: Management layer, Scheduling layer, Supervision layer and Execution layer. The Management layer gives out the weights of the orders to be accepted, and determine whether to accept the orders. The accepted orders are sent to the Scheduling layer for optimization in batches according to processing capability. The Supervision layer monitors the implementation of the Execution layer as scheduled.Based on the manufacturing system integration model, the system is divided into Integrated Manufacturing Managenment-Control (IMMC) subsystem and Open CNC subsystem. The IMMC subsystem realizes the functions of the Management layer, Scheduling layer and Supervision layer. The Open CNC subsystem behaves as the Execution layer. There are one central node and several outer execution nodes in a manufacturing system. Therefore, the system network is designed as star schema and implemented with Server-Client model.The IMMC subsystem includes Order Management subsystem, Job-shop Scheduling subsystem and Supervision subsystem. The Order Management subsystem sets calculation method for weights of orders. The hybrid Parthenon-genetic algorithm is introduced into the Job-shop Scheduling subsystem as an optimal scheduling algorithm. The scheduled results in standard format are saved in a database. TCP\IP network connection based on Socket technologies set up in the Supervision subsystemcan extract the optimal scheduled results in standard format and set the process status matrix for monitoring machines.Open CNC system consists of network connection module, NC code interpreter, processing information generation module and machine-driven signal module. The network connection module obtains the processing sequence from the monitoring subsystem and runs after permission. The NC code interpreter calls the related NC program from the standard NC code library in accordance with the processing sequence. After lexical and syntax analysis, qualified NC codes will be generated into machining code. The processing information generation module implements migration through interpolation algorithms for virtual machining. The signal module implements scalability and interchangeability for control of machine tools.The software is developed in Visual Studio 2005 and Visual C++. Experiments show that simulation or actual machining can be implemented according to the scheduled program under the supervision of the central control node. It is proved that the developed automation platform be of effectiveness and practicality.