Study On The Optimal Scheduling Method Of Machining Tasks For Green Manufacturing

Green manufacturing is a modern manufacturing mode with goals of reducing resource consumption and environmental impacts, which is the embodiment of sustainable development in manufacturing industry, and is also the important technical area and industry development trends concerned extensively by the developed countries. Manufacturing processes is one of the primary activities which directly consume resources, and discharge environmental emission. Therefore, it is the main goal of green manufacturing to reduce the resource consumption and environmental impacts caused by manufacturing processes.Machining is a typical kind of manufacturing process. Machining systems transform raw material or semi products into qualified final products or semi-final products by machining. Unfortunately, an amount of energy and material is consumed while a lot of waste and noise are discharged during the machining processes. At present, many researches have been carried on aiming at this issue, and some good solutions have been provided from the aspects of design and process planning. However, the research on the issue of reducing recourse consumption and environmental impacts at the operational of scheduling lever is rarely studied. With the foundation of the National Natural Science Foundation and National Key Project of Scientific and Technical Supporting Programs, this paper studies on the optimal scheduling method of machining tasks for green manufacturing, the details of which are presented below.As the basis of the research, the introduction of green manufacturing, the issues of green manufacturing in machining systems, and the scheduling problems have been presented. Experiments have shown that the different scheduling schema influent the resource consumption and environmental impacts during the machining processes even if the same batch of tasks are been machined by the same machine system. Based on it, the scheduling problem for machining systems integrating with resource and environmental factors has been proposed, the schematic description of this problem has been presented, and the comparison between the traditional scheduling problem and the proposed one has been analyzed from the purpose, the objectives, the approaches, and the results.The holistic model of the scheduling problem for green manufacturing has been established on the basis of the analysis of resource and environmental characteristics of machining systems. Firstly, the schematic framework of the holistic model has been built up, which consist of two primary parts of the analysis of resource and environmental characteristics and the scheduling model for green manufacturing. The analysis of resource and environmental characteristics is used for the scheduling objective sets of resource and environmental considerations, and the scheduling model for green manufacturing is a model framework with hierarchical configuration which is composed of the ideal model and the various practical models. The coefficient matrix about resource and environment is adopted to integrate the various objectives of resource and environmental factors into the scheduling models.With regards to the hierarchical model framework, the practical models have been studied including the saving-energy scheduling model, the saving-energy & reducing-noise scheduling model, and the resource & environmental scheduling model. Considering the parallel machines scheduling problem, the establishment of the three practical models and related coefficient matrix, the procedures of solving the models are introduced, and some examples are presented as well.Based on the research on the holistic model and practical models, the scheduling supporting system of machining tasks for green manufacturing has been developed, the function of which is benefit for the scheduling decision-making with consideration of resource consumption and environmental impacts. The architecture of the system is established, and the workflow, the design of function structure and database of the system are also given. The case in a certain gear machining shop floor is shown to demonstrate the system.