Energy Efficiency In Manufacturing Research Articles

Characterising Energy Efficiency of Electrical Discharge Machining (EDM) Processes

Energy efficiency in manufacturing has become a critical topic among researchers and industries. As a result, there has been a worldwide effort to improve the transparency of the energy efficiency for all manufacturing activities. The studies of unit processes have provided fundamental knowledge for characterising energy efficiency of manufacturing processes, which has been initially applied to conventional processes (e.g. turning, milling, injection moulding, etc.). However, studies in nonconventional manufacturing processes remain absent. This paper presented an empirical approach to characterise the energy efficiency of electrical discharge machining (EDM) processes. The derived model revealed a reverse relationship between specific energy consumption and material removal rate (MRR). Owing to the stochastic nature of EDM processes, the existing analytical and semi-empirical MRR models cannot practically predict the MRR. Alternatively, the empirical approach was also applied to test different theoretical MRR models and to derive coefficients for prediction purpose. As a result, the combined empirical models can predict the energy consumption of EDM processes with an accuracy of more than 90%. This methodology has been tested and validated for two ram EDM machines.

Energy KPI’s, Challenges for Sustainable Manufacturing Strategies, Analysis of Existing Rules and Indicators in an Industrial Environment in Relation to the Establishment of Energy Benchmark

As this paper demonstrates, benchmarking is a powerful concept for increasing a company's success. It visualizes the differences in performance through internal or external indicators and is applied in almost all corporate divisions successfully. An important part of the benchmarking process is the selection of indicators that allow for a significant comparison. The requirements linked to the indicators are derived from the objectives of the specific benchmarking project. The use of benchmarking with respect to energy efficiency in product manufacturing promises a transparent presentation of performance differences and the possibility to derive optimization potentials - provided that appropriate energy figures can be found. The future challenge is to develop a system with standardized billing and key energy indicators that enable a cross-comparison of the energy efficiency in the production. This project is described in the research project E|Benchmark, part of the research network Green Factory Bavaria and funded by the Bavarian State Ministry for Science, Education and Arts.

On a generalized approach to manufacturing energy efficiency

Energy efficiency has become a very significant factor, requiring its inclusion in the manufacturing decision-making attributes. This paper proposes a generalized approach to manufacturing energy efficiency. The basic element of the approach is the division of energy efficiency definition and study into four manufacturing levels, namely process, machine, production line, and factory. Process-level definitions are provided for the majority of manufacturing processes. A machine-level study indicates and solves difficulties, generated by the workpiece geometry, and points out the interaction with the process level through factors, such as the process time. Moreover, machine tool peripherals are responsible for a significant portion of the consumed energy, and classification based on the dependence of their consumption on process variables is required. Studies made on the production line and factory levels show that energy efficiency, at these levels, is heavily dependent on production planning and scheduling and can be improved through the appropriate utilization of machines, with the inclusion of shutdown and eco-modes. Finally, a case study is presented, showing that many of the difficulties towards the optimization of energy efficiency can be dealt with successfully, using the proposed generalized approach.

Ownership and Energy Efficiency in Indonesian Manufacturing

Using 1996 and 2006 census data on medium-large plants in Indonesian manufacturing, we examine whether foreign multinational enterprises (MNEs) and stateowned enterprises (SOEs) used purchased energy more efficiently than local, private plants, finding that the correlation between plant ownership and total energy intensity, gas intensity, and coal intensity was generally weak in both years. Second, we ask whether energy efficiency in private plants was affected by the presence of MNEs or SOEs in high-energy-consuming industries. In 1996, private energy intensities were often positively correlated with the presence of SOEs and majorityforeign MNEs and negatively correlated with the presence of wholly foreign or minority-foreign MNEs, but in 2006 the corresponding results differed substantially. This suggests that ownership-related differentials in energy intensity and intra-industry energy-intensity spillovers are not pronounced. If policymakers are concerned with improving energy efficiency in Indonesian manufacturing, plant ownership should not be a major consideration.

Energy Efficient Control Strategy for Machine Tools with Stochastic Arrivals and Time Dependent Warm-up

Energy efficiency in manufacturing is becoming a challenging goal due to the demand of this sector in the worldwide scenario. One of the measures for saving energy is the implementation of control strategies that reduce machine energy consumption during the machine idle periods. This paper extends a threshold policy, that switches off the machine during interruptions of part flow, by modelling explicitly the warm-up time as dependent on the time period the machine stays in low power consumption state. The optimal policy parameter is provided numerically for general distributions of the part arrival time and general functions modelling the warm-up time. Numerical results are based on data acquired with dedicated experimental measurements on a real machining center.

An implemented framework to estimate manufacturing-related energy consumption in product design

Manufacturing systems energy efficiency and the embodied energy of products are highly commented topics nowadays. So far, despite their interrelated nature, they have unfortunately been considered to be quite different from each other. Consequently, on one hand, product design remains as an unrecognised influence on the energy consumption of a manufacturing system, and on the other hand, manufacturing energy efficiency is unrealistically estimated in the calculation of product embodied energy. The present article integrates the existing literature on manufacturing energy consumption models and sets up a conceptual framework to assess the energy consumption of manufacturing systems from a product design perspective. This framework was implemented in a prototype software workflow, which was proven to generate interesting results for ecodesi gn and cleaner production initiatives. It helps in deriving realistic energy consumption values that can be linked to concrete product or process parameters, and therefore allows the improvement of product manufacturing energy efficiency at both design and manufacturing stages.

Therblig-based energy demand modeling methodology of machining process to support intelligent manufacturing

Energy efficiency has become an important factor that should be included in Intelligent Manufacturing due to the increasingly rising energy price and severe energy shortage issues. Energy demand modeling method is the foundation of improving the energy efficiency of manufacturing; therefore, an energy demand modeling methodology for machining processes is proposed. In this method, machining processes are divided into a series of activities, and Therblig, as one of the basic concepts of Motion study, is introduced to represent the basic energy demand unit. Moreover, a mathematical model of energy demand of machining processes is established by linking the activity and Therblig with machining state. Finally, case studies are performed to illustrate the validity and feasibility of the proposed methodology.

Eco-efficiency of manufacturing processes: A grinding case

Despite increased attention on energy-efficiency in manufacturing, other resources used as well as the quality performance of manufacturing processes have to be taken into account. This paper presents an eco-efficiency approach to evaluating energy as well as resource efficiency of manufacturing processes. The case of a grinding process is used to demonstrate the potential of the approach since e.g. coolant and dressing have an impact on quality performance and the environment. Based on the analysis, strategies for improving eco-efficiency of manufacturing processes are proposed.

Global manufacturing and the embodied energy of products

Manufacturing energy efficiency has become a key concern due to increasing energy costs and their associated environmental impact. It is important however, that investigations into the embodied energy of a product be in the context of global manufacturing rather than energy efficiency related to a particular product life cycle. This paper presents a model to assess the impact of global manufacturing on the embodied energy of products. Six different products manufactured from various raw materials in a global manufacturing network were used to carry out the assessment. The results show that product, material and key supply chain parameters play a crucial role.

Book Reviews

Book Reviews

Bounded Rationality and Organizational Learning

Abstract : If organization theory finds it useful to draw upon some of the ideas that have emerged in cognitive psychology, it will be advantageous to borrow also the terminology used in discussing these ideas. Without working toward a higher level of consistency in terminology than prevails in organization theory today, it will be difficult or impossible to cumulate and assemble into a coherent structure the knowledge we are gaining from individual case studies and experiments. We will be continually reinventing wheels. That is a luxury we cannot afford. The happy band of researchers on organization theory is sufficiently small to be kept fully occupied discovering and verifying the theory just once. (Author) (kr)