Therblig-embedded value stream mapping method for lean energy machining

Abstract

To improve energy efficiency, extensive studies have focused on the cutting parameters optimization in the machining process. Actually, non-cutting activities (NCA) occur frequently during machining and this is a promising way to save energy through optimizing NCA without changing the cutting parameters. However, it is difficult for the existing methods to accurately determine and reduce the energy wastes (EW) in NCA. To fill this gap, a novel Therblig-embedded Value Stream Mapping (TVSM) method is proposed to improve the energy transparency and clearly show and reduce the EW in NCA. The Future-State-Map (FSM) of TVSM can be built by minimizing non-cutting activities and Therbligs. By implementing the FSM, time and energy efficiencies can be improved without decreasing the machining quality, which is consistent with the goal of lean energy machining. The method is validated by a machining case study, the results show that the total energy is reduced by 7.65%, and the time efficiency of the value-added activities is improved by 8.12% , and the energy efficiency of value-added activities and Therbligs are raised by 4.95% and 1.58%, respectively. This approach can be applied to reduce the EW of NCA, to support designers to design high energy efficiency machining processes during process planning.

Analysis of Multi-Objective Optimization of Machining Allowance Distribution and Parameters for Energy Saving Strategy

“…According to Equation (4), the coefficients in the piecewise function of spindle rotation power P rm [W] were obtained by piecewise linear regressions, and the rotation speed n m ranges from 0 to 6000 rpm with the increment of 100 rpm. The results are shown as Equation 70: According to Equation 7, all these coefficients of the function for material cutting power P cm [W] can be obtained by using Taguchi experiments and statistical regression like Lv et al [29] and Jia et al [33].…”

“…The value of MRR depends on the machining type and for the turning process, MRR t can be expressed as Equation 14 [33].…”

Establishment of an Improved Material-Drilling Power Model to Support Energy Management of Drilling Processes

“…The material-drilling power is the tool-tip cutting power, and is solely related to the material removal during drilling process [20]. The material-drilling power, as an important part of total drilling power, establishing its Unfortunately, extensive studies have revealed that the energy efficiency of machine tools is generally less than 30% [11][12][13]. Therefore, the energy saving potential of machine tools is remarkable and energy efficiency improvement of machining processes has become a notable research area.…”

“…It can be seen that energy consumption and carbon emissions of machine tools are significant. Unfortunately, extensive studies have revealed that the energy efficiency of machine tools is generally less than 30% [11][12][13]. Therefore, the energy saving potential of machine tools is remarkable and energy efficiency improvement of machining processes has become a notable research area.…”

“…Turning, milling, drilling and grinding processes are widely used in the manufacturing industry [8]. Unfortunately, a large number of existing studies have shown that the energy efficiencies of the above machining processes are generally less than 30% [11][12][13]34]. Therefore, extensive existing studies have been carried out focused specially on energy modeling and the energy saving potential of turning [35,36], milling [37][38][39][40], grinding [41,42], and sandcasting processes [43].…”