A carbon efficiency approach for life-cycle carbon emission characteristics of machine tools

Reduction of carbon emissions of machine tools is an essential key to achieve low carbon manufacturing in various manufacturing system environments. To achieve this, the first step is to devise methods to understand and characterize the carbon emissions of machine tools. A carbon efficiency approach is presented to quantitatively characterize the life-cycle carbon emissions of machine tools, in which carbon efficiency is defined as the ratio of capacity or service value provided by machine tool to the corresponding carbon emissions. The life-cycle carbon emissions include two categories, fixed emissions and varied emissions which closely relate the throughput and operation time of machine tools. The dynamic characteristics of varied emissions are analyzed with the carbon efficiency functions of production rate, material remove volume, and economic return accordingly. The case study shows that light weight design and remanufacturing can reduce fixed emissions, and varied emissions can be reduced by improving energy efficiency and making the best matching of equipments and production tasks. (c) 2012 Elsevier Ltd. All rights reserved.