Energy-consumption allowance (ECA) is significant for improving the energy efficiency of manufacturing systems. A number of methods have been successfully used to establish the ECA for the process manufacturing industry, including the steel and chemical industries. However, it is difficult to establish the ECA for the discrete manufacturing industry due to the complexity and variety of energy consumption processes. Furthermore, there are no effective methods available for establishing the ECA of machining systems, a type of typical discrete manufacturing system. With wide distribution and great energy consumption in low efficiency, machining systems possess considerable energy-saving potential. In this study, from the perspective of workpiece moving, an energy-consumption model is proposed to establish the ECA of a workpiece in a machining system. The notion of the energy-consumption-step (ECS) is presented to describe various types of energy-consumption procedures in workpiece machining uniformly. Next, the architecture of the ECS is established, containing machining ECS, transportation ECS, storage ECS, various sub-ECSs and basic ECSs. Based on this architecture, an energy-consumption model for the whole machining process of a workpiece is proposed. The model helps establish the ECA of a workpiece and provide the quantity reference of each energy-consumption procedure in the whole process, and it exhibits significant promise for establishing the ECA of a machining system. Finally, a case study shows the practicability of the proposed model by establishing the primary ECA of a workpiece in a real machining workshop. (C) 2015 Elsevier Ltd. All rights reserved.
