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Winter M.,Joint German Australian Research Group on Sustainable Manufacturing and Life Cycle Management | Winter M.,TU Braunschweig | Ibbotson S.,Joint German Australian Research Group on Sustainable Manufacturing and Life Cycle Management | Ibbotson S.,University of New South Wales | And 4 more authors.
Journal of Cleaner Production | Year: 2015

To reduce the environmental impacts caused by manufacturing processes science, and industry want to identify hotspots and to derive improvement measures. One of those contributing manufacturing processes is grinding using synthetically produced cubic boron nitride (cBN). CBN grains are broadly applied for super abrasive materials in the production of high-precision grinding wheels. The shape, size and volume concentration of the cBN grains have a major impact on the technological results (workpiece roughness, tool wear, temperature, etc.) of the grinding process and on the economic value of the grinding wheel. Despite the technological results and the economic value, the contribution of cBN grinding wheels to the overall environmental impact has not been fully investigated and understood. A key method to calculate the environmental impact is life cycle assessment. However, an essential requirement is the availability of the used material and energy data during the life cycle stages of grinding wheel material, production, application and disposal. This paper gives an overview regarding the needed materials and energy during the different life phases of a cBN grinding wheel. On this basis, the detailed environmental impact of the grinding process is presented in a case study. © 2015 Elsevier Ltd.


Winter M.,Joint German Australian Research Group on Sustainable Manufacturing and Life Cycle Management | Winter M.,TU Braunschweig | Li W.,Joint German Australian Research Group on Sustainable Manufacturing and Life Cycle Management | Li W.,University of New South Wales | And 4 more authors.
Journal of Cleaner Production | Year: 2014

Grinding processes aim to produce workpieces with high technological characteristics, such as: fine surface finish, great geometrical accuracy and specific material properties, and specific economic objectives. Despite these technological and economic objectives, it is more and more important to consider the environmental impact of grinding processes. Therefore, the process eco-efficiency needs to be addressed in relation to the aforementioned three objectives. This paper presents an approach to identify the process parameters that leads to Pareto-optimal solutions for advancing the eco-efficiency of grinding operations. An internal cylindrical grinding process is selected to demonstrate this approach. Empirical models are developed to characterise the grinding processes. Both single-objective and multi-objective optimisations are carried out, where geometric programming and a weighted max-min model are used respectively. Furthermore, sensitivity analyses are presented to reveal the trends of each process parameter in relation to the preference of technological, economic and environmental objectives. © 2013 Elsevier Ltd. All rights reserved.


Dettmer T.,Joint German Australian Research Group on Sustainable Manufacturing and Life Cycle Management | Dettmer T.,TU Braunschweig | Ibbotson S.,Joint German Australian Research Group on Sustainable Manufacturing and Life Cycle Management | Ibbotson S.,University of New South Wales | And 6 more authors.
International Journal of Life Cycle Assessment | Year: 2015

Purpose: To address the non-renewable resource scarcity problem, vegetable oils have been used in many technical applications such as fuel and lubricants. In this context, cultivation of the oil-bearing plant Jatropha curcas is currently seen as one option. As renewable resources are limited as well due to their occupation of land, it is important to investigate which application of Jatropha oil provides the highest environmental saving potential compared to the current use of a non-renewable resource. Methods: This research investigated the potential environmental benefit of four technical applications of Jatropha oil by comparing them in a Life Cycle Assessment with the equivalent conventional products. Besides energy use (biodiesel), three examples of material use have been investigated: cold form oil (CFO), multifunctional oil (MFO), and a coolant emulsion. The service delivered by 1 kg of Jatropha oil was chosen as the functional unit resulting in specific reference flows for the different types of application. The centre of environmental science (CML) method was used to calculate the environmental impact results in six different impact categories (GWP, ADP, EP, AP, ODP, POCP). Furthermore, the influence of Jatropha cultivation on overall results was analyzed in a sensitivity analysis. Results and discussion: First, absolute results for the Jatropha products are given indicating the contribution of Jatropha oil supply chain, supply of other ingredients and biodiesel and lubricant production, respectively, use, and EoL phase. Second, relative results in comparison to conventional products are shown. Finally, the environmental benefit is calculated in, e.g., kilograms of CO2-equivalent per kilogram of Jatropha oil. Results reflect that the environmental benefits gained from using Jatropha oil for lubricants are higher than using it for biodiesel. The study showed that twice the amount of greenhouse gas (GHG) emissions can be saved per kilogram of Jatropha oil when Jatropha oil is used in lubricants like CFO instead of using it as biodiesel feedstock. In addition to a sensitivity analysis addressing agricultural practice in the Jatropha supply chain, the critical GWP for Jatropha oil production was calculated that would negate any environmental benefit over the conventional lubricant. Conclusions: The choice of an application may strongly influence the environmental effectiveness of a renewable material. To identify the environmentally preferable application for a given renewable material, calculating the environmental benefit per kilogram of applied material can be a helpful indicator. Future work is suggested on matching applications and renewables in a way to efficiently combine reduction of fossil resource depletion with further environmental goals like reduction of GHG emissions. © 2015, Springer-Verlag Berlin Heidelberg.


Ibbotson S.,Joint German Australian Research Group on Sustainable Manufacturing and Life Cycle Management | Ibbotson S.,University of New South Wales | Dettmer T.,Joint German Australian Research Group on Sustainable Manufacturing and Life Cycle Management | Dettmer T.,TU Braunschweig | And 4 more authors.
International Journal of Life Cycle Assessment | Year: 2013

Purpose: In recent years, the rising costs and infection control lead to an increasing use of disposable surgical instruments in daily hospital practices. Environmental impacts have risen as a result across the life cycle of plastic or stainless steel disposables. Compared with the conventional reusable products, different qualities and quantities of disposable scissors have to be taken into account. An eco-efficiency analysis can shed some light for the potential contribution of those products towards a sustainable development. Methods: Disposable scissors made of either stainless steel or fibre-reinforced plastic were compared with reusable stainless steel scissors for 4,500 use cycles of surgical scissors used in Germany. A screening life cycle assessment (LCA) and a life cycle costing were performed by following ISO 14040 procedure and total cost of ownership (TCO) from a customer perspective, respectively. Subsequently, their results were used to conduct an eco-efficiency analysis. Results and discussion: The screening LCA showed a clear ranking regarding the environmental impacts of the three types of scissors. The impacts of the disposable steel product exceeds those of the two others by 80 % (disposable plastic scissors) and 99 % (reusable steel scissors), respectively. Differences in TCO were smaller, however, revealing significant economic advantages of the reusable stainless steel product under the constraints and assumptions of this case study. Accordingly, the reusable stainless steel product was revealed as the most eco-efficient choice. It was followed by the plastic scissors which turned out to be significantly more environmentally sound than the disposable stainless steel scissors but also more cost-intensive. Conclusions: The overall results of the study prove to be robust against variations of critical parameters for the prescribed case study. The sensitivity analyses were also conducted for LCA and TCO results. LCA results are shown to be reliable throughout all assumptions and data uncertainties. TCO results are more dependent on the choice of case study parameters whereby the price of the disposable products can severely influence the comparison of the stainless steel and the plastic scissors. The costs related to the sterilisation of the reusable product are strongly case-specific and can reduce the economic benefit of the reusable scissors to zero. Differences in environmental and economic break-even analyses underline the comparatively high share of externalised environmental costs in the case of the disposable steel product. © 2013 Springer-Verlag Berlin Heidelberg.

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