Assessment and optimization of grinding process on AISI 1045 steel in terms of green manufacturing using orthogonal experimental design and grey relational analysis

In the production process, people usually pay more attention to the parts' technical performance and production cost while ignoring the influence of the production process on workers' health and the environment. Therefore, in this paper, the multi-objective optimization for grinding process with AISI 1045 steel was conducted to obtain the optimal scheme of the workpiece feed velocities, the depths of cutting and cooling/lubrication conditions. The residual stress, surface roughness, production cost, production rate, operator health and CO2 emission were evaluated as optimization objectives. A series of models were proposed and revised to apply to the flood and small quantity cooling/lubrication grinding conditions. Grinding is a high specific energy processing method, and the grinding surface of the metal workpiece usually generates large tensile residual stress due to excessive grinding heat, which does harm to the surface quality and fatigue life of products. Therefore the residual stress and surface roughness were evaluated as the technical benefit by experiments. The production rate and production cost as the economic benefit, the harm of grinding fluid to machine tools operators as the healthy benefit, and the CO2 emission as the environmental benefit were considered based on models. An orthogonal experiment was designed by Taguchi method. The contribution rates of each objective and their corresponding sub-objectives were calculated by grey relational analysis to avoid the correlation effects among different objectives. Finally, the grinding schemes were optimized by the range analysis and validated by experiments and calculations. The results show that the combined technical, economic, healthy and environmental benefits were improved significantly with the optimal scheme of workpiece feed velocity 2.4 mmin(-1), depth of cut 0.03 mm, and small quantity cooling/lubrication. It has an important reference value for green manufacturing. Besides, the feasibility of small quantity cooling/lubrication with water for the grinding process was proved. (C) 2019 Elsevier Ltd. All rights reserved.