Multi-objective parameter optimization of CNC plane milling for sustainable manufacturing

Energy optimisation for the combination of turning and drilling features using differential evolution

Cutting parameter optimisation is an effective way to realise energy-efficient machining. In previous studies, the cutting parameters of machining features of turning, milling, grinding, drilling, hobbing, and threading were optimised to decrease energy consumed by machine tools, and considerable energy savings were achieved. However, the energy consumption (EC) for each feature was separately optimised without systematic consideration of the negative effects on the EC for other features. The total EC for all features together probably increases. Hence, the trade-off amongst the reductions of EC for each feature needs to be jointly optimised. In our study, the external turning and drilling features are selected as examples to be combined. As a key novel contribution, we propose the integrated dimensional and cutting parameter optimisation problem about minimising the EC of Machine Tools for the combination of Turning and Drilling features (EMT-TD). In terms of optimisation, differential evolution (DE) is adopted to minimise the EMT-TD. According to case studies, DE obtained the optimal solutions within a computation time of 1 second. The optimal solutions achieved savings of 5.41%, 10.85%, and 7.19% of EMT-TD and savings of 2.23%, 5.90%, and 2.73% of machining time for three typical cases, respectively.

Introducing new green machining technology to enhance process performance and reduce environmental pollution in the metal processing industry

The pursuit of enhanced cooling and lubrication methods for machining processes that are energy-efficient, environmentally friendly, and cost-effective is receiving significant attention from both academia and industry. The reduction of CO2 emissions is closely tied to electrical and embodied energy consumption. This study introduces a novel LN2 oil-on-water (LNOoW) cooling/lubrication (lubricooling) approach for the machining of Ti-6Al-4V alloy. Machinability aspects, energy-related aspects, environmental-related aspects, and economic aspects are measured and compared. More specifically, surface quality, electrical energy, cutting forces, and tool wear were measured in machinability aspects. Similarly, specific total energy and specific cumulative Energy Demand (S_CED), specific carbon emission, and production costs were measured to investigate the energy and environmental and economic aspects, respectively. The LNOoW provided the best machinability results compared with other approaches. Result found that LNOoW produced 37.5% better surface quality, removed 159.17% more material, and reduced 50.56% specific cutting energy and 53.63% specific costs as compared to traditional dry cutting conditions. The 39% increment in specific carbon emissions observed in the LN2 oil-on-water (LNOoW) approach in comparison to the dry-cutting method can be mitigated through the implementation of sustainable practices in the production of liquid nitrogen (LN2). The information provided in this study serves as a valuable resource for the development of environmentally friendly machining processes. The study also helps get the sustainable development goals (SDGs) of the United Nations.

Multidimensional evaluation method and application based on life cycle carbon efficiency considering carbon emission, cost, and function

Low carbon research has currently become the most discussed environmental issue. Current comprehensive evaluation methods for low carbon consider carbon emission, cost, process parameters, and resource utilization, but the realization of low carbon may lead to cost fluctuations and functional changes and lack consideration of product functional requirements. Hence, this paper developed a multidimensional evaluation method for low-carbon research based on the association among three dimensions, namely, carbon emission, cost, and function. This multidimensional evaluation method was named life cycle carbon efficiency (LCCE), which is defined as the ratio between the value in the life cycle and the carbon emissions generated. The LCCE model was established, and then carbon emission calculation, cost assessment, and function quantification of the life cycle were performed according to the three dimensions. Case study and sensitivity analysis verified the feasibility of the proposed method. The method had comprehensive and accurate evaluation results, which provided theoretical support and optimized the low-carbon design.