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Nowadays, the main impetus to apply additive manufacturing (AM) of metals is the high geometric flexibility of the processes and its ability to produce pilot or small batch series. In contrast, resource and energy intensities are often not considered as constraints, even though the turnout of additive manufacturing is high, at least compared to chip removing processes.
The study at hand analyses the material characteristics and environmental impacts of a hose nozzle as an example of a commercial product of simple geometry. The production routes turning (conventional manufacturing) and laser beam melting (additive manufacturing) are compared to each other in terms of natural resource use, climate change potential and primary energy demand. It is found, that the product shows a lower demand for natural resources when produced via AM, but higher carbon emissions and energy demand when using a steel, that is mainly (80%) produced from high-alloyed steel scrap. However, different case studies during the sensitivity analyses showed that a number of factors highly influence the results: the steel source as well as the source of electricity play a major role in determining the environmental performance of the production routes. The authors also found that other production processes (here cold forging of tubes) might be an eco-friendly alternative to both routes, if feasible from an economic point of view.
In regard to the material characteristics, experimental testing revealed that the material advantages of AM produced hose nozzles (in particular higher yield strength) are reduced after a solution heat treatment is applied to the as-produced material, in order to increase corrosion resistance. However, products that do not require this production step might benefit from the higher yield strength, as a lower wall thickness could be realised.
Footprint calculators are efficient tools to monitor the environmental impact of private consumption. We present the results of an analysis of data entered into an online Material Footprint calculator undertaken to identify the socioeconomic drivers of the Material Footprint in different areas of consumption, from housing to holidaymaking. We developed regression models to reveal (1) the impact of socioeconomic characteristics on Material Footprints of private households and (2) correlations between the components of Material Footprints for different arrays of consumption. Our results show that an increasing Material Footprint in one array of consumption comes with an increasing Material Footprint in all other arrays, with the exception of housing and holidaymaking. The socioeconomic characteristics of users have a significant impact on their Material Footprints. However, this impact varies by the array of consumption. Households only exhibit generally bigger Material Footprints as a result of higher incomes and larger dwellings. We conclude that indicators which strive to monitor resource efficiency should survey disaggregated data in order to classify the resource use to different population groups and arrays of consumption.
Green Information Systems in general, and footprint calculators in particular, are promising feedback tools to assist people in adopting sustainable behaviour. Therefore, a Material Footprint model for use in an online footprint calculator was developed by identifying the most important predictors of the Material Footprint of the calculator's users. By means of statistical learning, the analysis revealed that 22 of the 95 predictors identified accounted for 74% of the variance in Material Footprints. Ten predictors out of the 95, mainly from the mobility domain, were capable of showing a prediction accuracy of 61%. The authors conclude that 22 predictors from the areas of mobility, housing and nutrition, as well as sociodemographic information, accurately predict a person's Material Footprint. The short and concise Material Footprint model may help developers and researchers to enhance their information systems with additional items while ensuring the data quality of such applications.