Failure Mode and Effect Analysis and Analytic Hierarchical Process Applied for Reduction of Environmental Risk in Supplier Selection to Thermoplastic Industry

Method of Fuzzy Analysis of Qualitative-Environmental Threat in Improving Products and Processes (Fuzzy QE-FMEA)

“…The assumptions were assumed based on the FMEA methodology, assumptions for decision making based on multiple criteria in a fuzzy decision environment, and also based on the literature review. The assumptions for the modified FMEA method, i.e., for fuzzy QE-FMEA method were following: products or processes to be analysed are arbitrary with the use of adequate priority number selection tables [ 1 , 3 , 37 ]; quality is expressed by the Z index (i.e., the importance of the defect for the customer) and refers to the effect of the defect on the use of the product/or the functioning of the process, the impact on customer satisfaction and possible repair costs) [ 7 , 29 , 38 ]; the impact on the natural environment (indicator E) is the negative impact of a defect (product or process) on the natural environment [ 4 , 12 , 38 ]; the threat priority value (RQE) is calculated in a fuzzy decision-making environment and is a quotient of the ratings assigned to the indicators, i.e.,: P—probability of a defect, W—possibility of detecting a defect, Z—effect (significance) of the defect (so-called quality), E—impact on the natural environment, where Z and E are combined and created qualitative environmental indicator (QE) and are evaluated simultaneously in the pairwise comparison matrix [ 2 , 30 , 39 , 40 ]; when determining the number Z (significance of the defect), only the effect of the defect should be considered; determining the number P (the probability of a defect) may refer to the defect but also to the cause of the defect, it is necessary to consistently comply with the adopted rule; determining the number W (the possibility of detecting a defect) refers to the cause of the defect; criteria for assessing indicators P (probability of a defect), W (possibility of detecting defects), and QE (qualitative-environmental indicator) result from the subject of the analysis and are selected individually by a team of experts, considering, for example, the frequency of incompatibilities, their effects, and causes; the QE indicator results from the relationships occurring in a fuzzy decision-making environment and the nine-point Saaty scale [ 3 , 12 , 33 ]. …”

“…the threat priority value (RQE) is calculated in a fuzzy decision-making environment and is a quotient of the ratings assigned to the indicators, i.e.,: P—probability of a defect, W—possibility of detecting a defect, Z—effect (significance) of the defect (so-called quality), E—impact on the natural environment, where Z and E are combined and created qualitative environmental indicator (QE) and are evaluated simultaneously in the pairwise comparison matrix [ 2 , 30 , 39 , 40 ];…”

“…Indicator assessments are adequate: P—probability of defect, W—possibility of defect detection, Q—the effect (significance) of the defect (so-called quality), E—impact on the natural environment, where Q and E are combined and create qualitative-environmental indicators (QE) [ 30 , 39 , 40 ].…”