Sami Kara

An empirical model for predicting energy consumption of manufacturing processes: a case of turning process

Optimizing the energy efficiency of processes has become a priority in the manufacturing sector; driven by soaring energy costs and the environmental impact caused by high energy consumption levels. The energy consumed by a machine tool performing a turning process consists of not only the energy required by the tool tip for material removal but also the energy used for auxiliary functions. Traditionally, the energy required for the cutting process is estimated based on cutting force prediction equations. However, this estimation is limited to the energy consumption of the tool tip. Thus, the aim of this paper is to develop a reliable method to predict the total energy consumption of a selected machine tool performing a turning operation. In order to compare the energy consumption under different cutting conditions, the specific energy consumption is defined as a functional unit: the energy consumed to remove 1 cm3 of material. An empirical model is obtained based on power measurements under various cutting conditions, and it is able to provide a reliable prediction of energy consumption for given process parameters. Additional investigations are conducted in order to understand and explain each coefficient in the energy consumption model.

Sustainable product development and manufacturing by considering environmental requirements

Abstract Sustainability in the development and manufacture of new products is a strategy that is widely accepted in principle, although not yet widely practiced. The integration of environmental requirements throughout the entire lifetime of a product needs a new way of thinking and new decision tools to be applied. This paper describes the concept of an approach to product development, based on a paradigm for sustainable manufacturing. Four examples of methodologies and decision tools are discussed, representing the most important sources of environmental impacts of a product. The emphasis lies on the integrating concept rather than on the details of the methodologies.

An Investigation into Fixed Energy Consumption of Machine Tools

Improving energy efficiency of manufacturing processes requires knowledge about the energy consumption as a function of the machine tool and cutting process itself. Both theoretical and empirical models of unit process energy consumption have emphasized the relevance of fixed energy consumption which ensures the machine readiness. However, the machine tool behavior during the stand-by mode is lack of thorough study. This paper presented the investigation of fixed energy consumption from definition and description to improvement strategies. Six machine tools covering different manufacturing processes are selected for this investigation in order to evaluate the future savings.

Electricity Metering and Monitoring in Manufacturing Systems

Traditionally, electricity costs in manufacturing have been considered as an overhead cost. In the last decade, the manufacturing industry has witnessed a dramatic increase in electricity costs, which can no longer be treated as an overhead, but a valuable resource to be managed strategically. However, this can only be achieved by strategically gathering electricity consumption data by metering and monitoring. This keynote paper presents the latest developments and challenges in electricity metering and monitoring systems and standards in the context of manufacturing systems. An industry case is presented to emphasise the challenges and the possible solutions to address them.

Impact of energy efficiency on computernumerically controlled machining

Abstract Increasing environmental demands from governmental bodies and customers stress the importance of companies improving their environmental performance. The research presented here shows that productivity and cost efficiency improvements can be achieved alongside energy savings in a computer numerically controlled machining environment. This improves the profitability of the companies, but also leads them towards more sustainable and environmentally aware manufacturing; the relationship between machining parameters, machining costs, and energy consumption is evaluated. From this perspective, it is important that production planners etc. understand the methodological possibilities for improvements in cost and energy efficiency. The current research is based on a machining cost model and experiments where energy consumption and tool wear were monitored.

Analysis of the bullwhip effect in multi-product, multi-stage supply chain systems–a simulation approach

This research aims to develop a simulation approach based on system dynamics modelling (SDM) and adaptive network based fuzzy inference system (ANFIS) for quantifying and reducing the bullwhip effect in a multi-product, multi-stage supply chain. The proposed model is comprised of three groups of variables influencing the bullwhip effect, namely the structure of a supply chain network, supply chain contributions (ordering process in regular situation or when a supplier has a promotion or shortage gaming) and supply chain performances (the number of defects and ordering lead time). As a result, a two layer simulation model is developed with three generic models. The flexibility of this proposed approach is its ability to model various types of ordering policies which are basic inventory policies, material requirement planning (MRP) system and just in time (JIT) approach. The supply chain of a beverage company was selected to validate and demonstrate the flexibility of the proposed model. The findings of the proposed simulation model are consistent with the results obtained from the case study. The error magnitude of the bullwhip effect level varied between 0 and 9% resulting in bullwhip effect reductions of up to 92%. Accordingly, the bullwhip effect levels are significantly decreased by using the proposed simulation model.

Reverse logistics strategies for end‐of‐life products

Purpose – End‐of‐life (EOL) products have become a major environmental issue among countries and manufacturers. This is due to the growing number of EOL products and their hazardous contents. Many collection strategies and pilot projects have been conducted to manage EOL products, especially Waste Electrical and Electronics equipments (WEEEs). However, as characteristics of a population are different to one another, a customized collection strategy is required. The purpose of this paper is to find an effective collection strategy which considers cost and environmental impact simultaneously.Design/methodology/approach – This paper presents an integrated collection strategy which combines a Fuzzy Colored Petri Net forecasting method and collection network model to collect EOL products. Colored Petri Net is used in modeling the integrated collection strategy. To test the collection strategy, a case study on mobile phone collection in Australia is presented.Findings – The integrated collection strategy develo...

Selective disassembly sequencing : A methodology for the disassembly of end-of-life products

Disassembly planning has become an important strategic issue in order to reduce the environmental impact and increase the value of end-of-life (EOL) products. However, in order to make the recovery of EOL products viable, optimal disassembly sequencing has to be determined for each reusable component. In this paper, a selective disassembly methodology for EOL products is presented, which was developed by reversing and modifying the methodology developed by Nevins and Whitney (1989) for assembly. In the new methodology, the disassembly sequence generation and selective part recovery are largely performed by a special computer software. A number of product case studies were used to prove the concept and demonstrate the efficiency of the methodology.

Manufacturing flexibility and variability: an overview

Flexibility has become one of the most useful and necessary weapons in many of todays competitive markets. For companies in situations considering investments in flexibility, it is necessary to assess carefully exactly what flexibility could benefit the companys operations, and how this flexibility can be achieved. Different manufacturing situations are associated with different levels of uncertainty and variations, and therefore call for different sorts of flexibility. Although flexibility has been argued to be available (to a certain point) without major investments in technology, it can be assumed that flexibility is most likely to come at a price. A company should therefore spend considerable effort on identifying what flexibility would be of benefit to the organisation to enhance their performance, and thereafter assess how to achieve it. This paper provides a comprehensive analysis of variability and uncertainty, and therefore, the need for flexibility within an organisation by examining market and manufacturing process related factors. Each factor is further examined to find out relevant flexibilities and corresponding methods, tools, and techniques to be used by suggesting proposed manufacturing approaches to organisations. The human factor is suggested as an essential flexibility component as well as a key contributor for selecting, developing, improving and implementing flexibilities in order to succeed in markets that are accelerating and becoming more turbulent.

A selective disassembly methodology for end‐of‐life products

Purpose – Aims to develop a selective disassembly methodology for generating an optimum disassembly sequence for end‐of‐life (EOL) products.Design/methodology/approach – The paper presents a selective disassembly methodology for EOL products. In order to achieve this, Nevins and Whitneys methodology for assembly was modified. In addition, a Java‐based software was developed to speed up the generation of all possible disassembly sequences.Findings – Finds that the methodology developed by Nevins and Whitney for assembly is applicable to disassembly process. In addition, the winnowing process for disassembly is much easier than for assembly because of the selective disassembly approach, which automatically provides a significant constraint on possible sequences.Research limitations/implications – Provides an easy to use and visual disassembly sequence generation tool for end‐of‐life products.Practical implications – Disassembly is one of the significant cost drivers in achieving close loop manufacturing. A...