Many different standards and methodologies exist to evaluate the environmental impacts of products, processes and manufacturing systems. The most commonly used method is Life Cycle Assessment (LCA), including its variants process LCA, Economic Input-Output LCA and hybrid LCA [REIC10]. Reich-Weiser et al. [REIC10] discussed the differences between frameworks and sorted them into different spatial and temporal levels of complexity. Hybrid LCA methodologies were found to be effective at capturing full supply chain and enterprise level emissions; however, trade-offs at the factory or machine tool level are best analyzed by process LCA approaches [REIC10]. LCA focuses on environmental aspects.
ISO14040 gives a framework to conduct a process LCA. Figure 7.1 transfers the framework to grinding tool production. First, goal and scope of the study are defined as well as functional unit, i. e. the basis for the quantification of resource and energy streams. In the next step, life cycle inventory (LCI) analysis, all resource and energy streams are collected. Table 7.1 summarizes common environmental attributes, but are not grinding process specific. For grinding analysis, water, air, sound, resources, and human aspects are most important.
The third step consists of the life cycle impact assessment (LCIA). The inventory data is converted into impact indicators, which will form the environmental fingerprint of the process. Impact is defined as the consequences caused by the input and output streams on the Areas of Protection (AoP). Four AoP are defined: human health, man-made environment, natural environment, and natural resources [DEHA99]. Typical impact categories enclose global warming, stratospheric ozone
|
1. Goal and Scope Definition e. g. goal: benchmark of grinding wheels, scope: whole life cycle, functional unit: 1 grinding wheel |
О |
|
|
2. Inventory Analysis (LCI) e. g. resources and energy in raw material production, tool manufacturing, tool use (grinding process), tool end of life |
о |
4. Interpretation |
|
£ |
||
|
3. Life Cycle Impact Assessment (LCIA) e. g. green house gas emissions, ocean depletion, acidification |
о |
|
Fig. 7.1 Life cycle assessment of abrasive tooling systems (after ISO14044) |
|
Table 7.1 Environmental attributes [JAIN12, p. 459 ff]
|
depletion, acidification, eutrophication, photochemical smog, terrestrial toxicity, aquatic toxicity, human health, resource depletion, land use, and water use [CURR06, p. 49].
LCIA methods are either midpoint or endpoint oriented. The midpoint methods model impacts at some midpoint in the environmental mechanism [HAUS05]. The endpoint methods are also called damage oriented methods and calculate an overall impact score for the AoP at the end [HAUS05]. Normalization and weighting is conducted on the impact indicators. The environmental attributes in Table 7.1 have been of interest to life cycle assessment over time [JAIN12, p. 459 ff].