Methods for evaluation of energy efficiency of machine tools

Energy efficiency of machine tools proves to be an ongoing challenge to manufacturing industries as a number of international initiatives shows. The first part of the ISO 14955 series focusses on the basic understanding, power metering and energy efficient design of machine tool. The ISO standardization body (ISO/IC 39 WG 12) is currently working on the second part of the ISO 14955 series, which aims at defining of a standardized test method. However, a method meant for standardization could not been identified yet, due to the versatile advantages and disadvantages of the different test methods. In order to find the most feasible test method for standardization, four general energy efficiency test methods are described and compared in a state-of-the-art review. The test methods are then evaluated against seven key characteristic criteria using the Analytic Hierarchy Process (AHP), a structured multiple criteria decision-making technique. The criteria selection and judgement of their relative importance has been carried out in collaboration with experts from the machine tool industry and research institutes. Hence, weight factors are derived and the best suited test method for both industrial application and standardization is identified. The validity of the evaluation results is proven using the geometric consistency method. (C) 2015 Elsevier Ltd. All rights reserved.