Study On Evaluation And Redesign Methods Of Machine Tool Remanufacturing

The quantity of machine tools in China is about eight million and ranks first in theworld，however, most of the machine tools are backward in technique and areconfronted with retirement and scrapping due to technology or function. Machine toolremanufacturing, as a new manufacturing model of machine tool based on reusing theused resources, is the best solution for the problems of dispose of the numerous usedmachine tools all over our country, in line with China’s strategic needs of developingrecycling economy, implementing energy saving and emission reducing, and addressingclimate change. Remanufacturability evaluation and redesign are key technologies ofmachine tool remanufacturing, requiring for support from related theories and methodsurgently.With the support of the11th Five-YearNational Key Technology R&DProgram(2006BAF02A20),the12th Five-YearNational Key Technology R&D Program(NO.2011BAF11A09) and other projects, methods of remanufacturability evaluationand redesign for machine tool remanufacturing are studied integrated with advanceddesign theory of machine tool and the practice experience of machine toolremanufacturing, which can provide technology support for the industry development ofmachine tool remanufacturing.Firstly, the definition and connotation of machine tool remanufacturing arepresented based on the analysis of the common features and differences betweenmachine tool remanufacturing and machine tool repair or rebuild, new machine toolmanufacturing. Combined with the actual demand, a process model of machine toolremanufacturing oriented to life-cycle is established, and then the view models ofobjective, redesign, process, technology framework, quality control, resourceconsumption and environmental impact for machine tool remanufacturing are presentedto analyze the remanufacturing process.Secondly, the process of remanufacturability evaluation of used machine tool ispresented, in which technology feasibility, economic feasibility and environmentalbenefits of machine tool remanufacturing are the evaluation indexes. In addition, thequantification methods for each index are proposed and the weights for each index aredetermined. Then, an integrated method for evaluating the remanufacturability of usedmachine tool oriented to remanufacturing process is proposed, and it is applied to the remanufacturing process of used planer B2025to examine its feasibility and validity.Thirdly, based on the analysis of the features of reuse-oriented redesign, a novelreuse-oriented customized redesign method of used machine tools based on axiomaticdesign theory is presented, including the process of customer demand analysis,conceptual redesign and process design. In addition, the process of conceptual redesignis analyzed in detail, which is applied to lathe remanufacturing, such as the processes offunction feature planning based on QFD, structure redesign, etc. Then, an optimizationmodel is constructed based on unbalanced transportation problem to match and optimizethe reuse relationship between the cores and the designed module family for diversedemands.Fourthly, the process of machine tool remanufacturing is introduced and theprocess scheme design of machine tool remanufacturing is analyzed, includingmechanical parts remanufacturing, NC and electrical systems retrofitting. In addition,the machine-based comprehensive upgrading scheme is analyzed from the views ofenergy-saving, environmental friendliness and informationization.Then, the evaluationindex system of machine tool remanufacturing that includes economy, technology,resource and environment is established, and the evaluation method of machine toolremanufacturing scheme based on entropy weight and analytic hierarchy process (AHP)is proposed.Finally, the practices of machine tool remanufacturing in Chonqing Machine ToolGroup. is analyzed. The remanufacturing scheme of YX3120gear hobbing machine ispresented based on the customer demand analysis and the economic and social benefitsare analyzed.