# New Possibilities of Using DEMATEL and ERPN in the New PFMEA Hybrid Model
## 3 Results and Discussion
### Hybrid Model PFMEA-DEMATEL-ERPN  
#### 3.5.1 Proposal of Measures  
By proposing four measures, we want to improve the original state achieved by the conventional PFMEA. An important parameter for meeting the objectives of the work is the probability of occurrence of failure modes O. The failure modes have 11 equal values (for FM2-12 is O = 2) and 1 abnormally high value (FM1 = 8). Therefore, the FM1 mode has been a matter of priority, as there was a human error in updating the data. Failure mode 1 was not \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{**Failure Mode**} & \multicolumn{4}{c}{**Initial PFMEA**} & \multicolumn{4}{c}{**PFMEA with ERPN**} & \\ \hline  & **S(ST)** & **O** & **D** & **RPN** & **CI** & **PO** & **PD** & **SI** & **SE** & **poc** & **ERPN** & **CI** \\ \hline FM1 & 8 & 10 & 1 & 80 & 9–10 & 1 & 1.000 & 1 & 1 & 0 & 8.00 & 9 \\ FM2 & 2 & 7 & 6 & 84 & 5–8 & 0.7 & 0.444 & 35.5 & 86.1 & 0 & 89.06 & 2 \\ FM3 & 6 & 2 & 7 & 84 & 5–8 & 0.2 & 0.333 & 3.1 & 3.1 & 0 & 3.72 & 10 \\ FM4 & 8 & 2 & 5 & 80 & 9–10 & 0.2 & 0.556 & 2 & 2 & 0 & 3.20 & 11 \\ FM5 & 7 & 2 & 5 & 70 & 11 & 0.2 & 0.556 & 67.9 & 88.6 & 0 & 107.94 & 1 \\ FM6 & 6 & 2 & 7 & 84 & 5–8 & 0.2 & 0.333 & 1.5 & 38.3 & 0 & 31.24 & 7 \\ FM7 & 6 & 2 & 7 & 84 & 5–8 & 0.2 & 0.333 & 1 & 1.1 & 0 & 1.28 & 12 \\ FM8 & 8 & 2 & 7 & 112 & 1/2 & 0.2 & 0.333 & 5.3 & 29.3 & 0 & 34.08 & 6 \\ FM9 & 8 & 2 & 6 & 96 & 4 & 0.2 & 0.444 & 2 & 31 & 0 & 28.98 & 8 \\ FM10 & 8 & 2 & 4 & 64 & 12 & 0.2 & 0.667 & 23.1 & 43.4 & 0 & 47.79 & 5 \\ FM11 & 8 & 2 & 7 & 112 & 1/2 & 0.2 & 0.333 & 6.5 & 64.9 & 0 & 72,85 & 4 \\ FM12 & 7 & 2 & 7 & 98 & 3 & 0.2 & 0.333 & 21.4 & 79 & 0 & 83.72 & 3 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Representation of PFMEA with the ERPN model. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline  & & \multicolumn{4}{c}{**INITIAL PFMEA**} & \multicolumn{4}{c}{**DEMATEL**} & \multicolumn{4}{c}{**ERPN**} \\ \hline  & **n** & **O** & **RPN** & **CI** & **n\({}_{\mathbf{n}}\)** & **KI** & **Significance** & **Influence** & **ERPN** & **CI** \\ \hline FM1 & 18,100 & 10 & 80 & 9–11 & 362 & 12 & 12 & effect & 8.00 & 9 \\ FM2 & 2000 & 2 & 84 & 5–8 & 40 & 2 & 2 & casual & 89.06 & 2 \\ FM3 & 2100 & 2 & 84 & 5–8 & 42 & 1 & 1 & casual & 3.72 & 10 \\ FM4 & 2000 & 2 & 80 & 9–11 & 40 & 11 & 9 & effect & 3.20 & 11 \\ FM5 & 2200 & 2 & 80 & 9–11 & 44 & 4 & 5 & casual & 107.94 & 1 \\ FM6 & 2200 & 2 & 84 & 5–8 & 44 & 10 & 11 & effect & 31.24 & 7 \\ FM7 & 2100 & 2 & 84 & 5–8 & 42 & 6 & 10 & casual & 1.28 & 12 \\ FM8 & 2200 & 2 & 112 & 1–2 & 44 & 7 & 3 & effect & 34.08 & 6 \\ FM9 & 2100 & 2 & 96 & 4 & 42 & 3 & 4 & casual & 28.98 & 8 \\ FM10 & 2100 & 2 & 64 & 12 & 42 & 8 & 6 & effect & 47.79 & 5 \\ FM11 & 2000 & 2 & 112 & 1–2 & 40 & 9 & 7 & effect & 72.85 & 4 \\ FM12 & 2100 & 2 & 98 & 3 & 42 & 5 & 8 & casual & 83.72 & 3 \\ \(\Sigma\) & 41,200 & & & & 824 & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Analysis of important parameters after creating conventional FMEA, DMEATEL model, and ERPN. considered in the final statistical evaluation in the other models. By solving the FM1 failure mode, the incidence of failure modes was reduced to 462, which represents 1.12%. Measures for the model of the conventional PFMEA (according to the highest RPN):  
* FM8--Increasing the amount of oil in the event of the formation of a vacuum bubble (the part remains stuck in the tool), the holes in the affected area responsible for the occurrence must be blinded, the release of tension elements if necessary;
* FM9--Tool setting (position of guiding elements);
* FM11--Tool maintenance;
* FM12--Production of a longer punch/underlaying of the existing punch; optimization of the internal diameter of the shear to a larger value.