Energy Efficiency Evaluating Of The Mechanical Machining System

The mechanical machining system is featured with enormous quantity and wide use, and it consumes a lot of energy with very low energy efficiency; therefore, the energy saving and emission reduction potentials in the machining system are great. Energy efficiency evaluation of the machining system is to evaluate its energy consumption state and process, and its energy efficiency. It is the basis to reduce its energy consumption and improve its energy efficiency. Energy efficiency evaluating technology is a hot topic being studied in the world, it is also an urgent needing technology for the sustainable development of the mechanical manufacturing industry in China.Due to the multiple sources and complex construction of the machining system, and the dynamic and stochastic characteristics of the energy consumption state and process, it is hard to evaluate the energy efficiency of the machining system comparing to the continuous manufacturing system. Combining with the project financed by the National High Technology Research & Development Program of China(863 Program) and the projects financed by the Natural Science Foundation of China, the energy efficiency model, energy efficiency evaluating index system and energy efficiency evaluating method are studied in this paper.Firstly, the extended connotation of energy efficiency of the machining system is analyzed, and the energy models are established including the multiple sources mathematical model of the CNC machine tool, the work-piece energy model oriented to the machining process, and the workshop energy model based on fixed power and varied power; and then the energy efficiency models are advanced based on the energy models above, including the energy efficiency model of the machine tool, work-piece and the whole workshop.Secondly, the characteristics of the energy efficiency evaluation on the machining system are analyzed, including distribution feature and variation feature, and a set of energy efficiency evaluating index system is proposed, in which, the evaluating index is constructed based on the energy efficiency model and integrating the energy utilization and specific energy consumption, and a kind of integrating index acquiring method is given as well.And then, the energy efficiency evaluating method of the machining system is proposed after a brief review on the energy efficiency evaluating method of the mechanical manufacturing system, which includes the energy efficiency evaluating procedure of the machining system, the energy efficiency evaluating standard of the machining process, and the dynamic energy efficiency evaluating method of the machining system based on simulation technology.The energy efficiency evaluating procedure of the machining system is advanced in this paper and the six steps are studied, which are boundary definition of the evaluation, evaluating index determination, energy efficiency data collection, evaluating tool selection, evaluating result output and evaluating report generation; The energy efficiency evaluating standard is established, and the standard rules the mathematical model and index system of the energy efficiency evaluation of the machining process, meanwhile it also gives the index acquiring method integrated the offline basic data acquisition with online input power acquisition, so that precision enough evaluating results can be obtained just by acquiring the input power of the machining system on the site, to provide support for the energy efficiency evaluation and optimization of machine tool and work-piece; a dynamic energy efficiency evaluating method based on Petri net is established, where the energy consumption model of the machining system is set up based on Petri net theory, and it is simulated with the Petri net simulation software to get the energy efficiency of the machining process, so that dynamic evaluation is achieved.Finally, the framework and the primary business flow of the energy efficiency evaluating supporting system for the machining system is designed.