## 2 Methodology
### Fuzzy FMEA-Based MDF Continuous Pressing  
This paper refers to the method of fuzzy calculation in [22]. This method is used to solve the evaluation of the shipboard integrated power system. It is similar to the method used in this paper to solve the problem of the quality control of the CHP process of MDF. This method can be applied to solve similar problems. Therefore, this article cites this method for the research in this article. The equations for applying the article's method are listed below:  
\[\left\{ \begin{array}{l}r_{j}=\sum\limits_{k=1}^{3}r_{jk}\\ \pi_{jk}=r_{jk}/r_{j}\\ H(r_{j})=-\sum\limits_{k=1}^{3}\pi_{jk}\ln\pi_{jk}/\ln 3\end{array} \right. \tag{3}\]  
where \(r_{jk}\) is the evaluation of expert \(j\) linked to the \(k^{\text{th}}\) performance index and \(r_{j}\) and \(H_{rj}\) are the total scores and entropy score for an expert. Then, the total entropy and the entropy weights of expert reliability can be set using:  
\[\left\{ \begin{array}{l}E_{e}=\sum\limits_{j=1}^{M}H(r_{j})\\ \theta_{j}=H(r_{j})/E_{e}\end{array} \right. \tag{4}\]  
Suppose \(X_{j}\) is the credibility weight coefficient, which is assigned by taking into account the system familiarity, membership qualifications, and assessment environment. Correspondingly, the total credibility score of the expert, which is expressed as the normalized sum of the entropy and qualitative weights, is given by:  
\[h_{j}=(\theta_{j}+Xj)/(\sum\limits_{j=1}^{M}+X_{j}) \tag{5}\]  
The expert evaluations of the trapezoidal fuzzy number defined by three risk factors with regards to the failure mode are expressed as \(S_{ij}=(S_{ij}^{L},S_{ij}^{M_{1}},S_{ij}^{M_{2}},S_{ij}^{U})\), \(O_{ij}=(O_{ij}^{L},O_{ij}^{M_{1}},O_{ij}^{M_{2}},O_{ij}^{U})\), respectively. As a result, the final fuzzy evaluations of risk factors related to the \(i^{\text{th}}\) failure mode can be defined as:  
\[\left\{ \begin{array}{l}S_{i}=\sum\limits_{j=1}^{M}h_{j}S_{ij}=\left(\sum \limits_{j=1}^{M}h_{j}S_{ij}^{L},\sum\limits_{j=1}^{M}h_{j}S_{ij}^{M_{1}}, \sum\limits_{j=1}^{M}h_{j}S_{ij}^{M_{2}},\sum\limits_{j=1}^{M}h_{j}S_{ij}^{U} \right)\\ O_{i}=\sum\limits_{j=1}^{M}h_{j}O_{ij}=\left(\sum\limits_{j=1}^{M}h_{j}O_{ij }^{L},\sum\limits_{j=1}^{M}h_{j}O_{ij}^{M_{1}},\sum\limits_{j=1}^{M}h_{j}O_{ ij}^{M_{2}},\sum\limits_{j=1}^{M}h_{j}O_{ij}^{U}\right)\\ D_{i}=\sum\limits_{j=1}^{M}h_{j}D_{ij}=\left(\sum\limits_{j=1}^{M}h_{j}D_{ij }^{L},\sum\limits_{j=1}^{M}h_{j}D_{ij}^{M_{1}},\sum\limits_{j=1}^{M}h_{j}D_{ ij}^{M_{2}},\sum\limits_{j=1}^{M}h_{j}D_{ij}^{U}\right)\end{array} \right. \tag{6}\]Let \(\omega_{Sj}=(\omega_{Sj}^{L},\omega_{Sj}^{M},\omega_{Sj}^{U})\), \(\omega_{Oj}=(\omega_{Oj}^{L},\omega_{Oj}^{M},\omega_{Oj}^{U})\), and \(\omega_{Dj}=(\omega_{Dj}^{L},\omega_{Dj}^{M},\omega_{Dj}^{U})\) be triangular fuzzy values of the relative importance scores of three risk factors as done by an expert [28]. Next, the final fuzzy values of the risk factor weights can be expressed as:  
\[\left\{ \begin{array}{l}\omega_{S}=\sum\limits_{j=1}^{M}h_{j}\omega_{Sj}=( \sum\limits_{j=1}^{M}h_{j}\omega_{Sj}^{L},\sum\limits_{j=1}^{M}h_{j}\omega_{Sj }^{M},\sum\limits_{j=1}^{M}h_{j}\omega_{Sj}^{U})\\ \\ \omega_{O}=\sum\limits_{j=1}^{M}h_{j}\omega_{Oj}=(\sum\limits_{j=1}^{M}h_{j} \omega_{Oj}^{L},\sum\limits_{j=1}^{M}h_{j}\omega_{Oj}^{M},\sum\limits_{j=1}^{ M}h_{j}\omega_{Oj}^{U})\\ \\ \omega_{D}=\sum\limits_{j=1}^{M}h_{j}\omega_{Dj}=(\sum\limits_{j=1}^{M}h_{j} \omega_{Dj}^{L},\sum\limits_{j=1}^{M}h_{j}\omega_{Dj}^{M},\sum\limits_{j=1}^{ M}h_{j}\omega_{Dj}^{U})\\ \end{array} \right. \tag{7}\]  
The fuzzy RPN is set as the fuzzy-evaluated geometric mean of three risk factors as follows:  
\[\exp\left[\sum\limits_{\lambda=1}^{3}(\omega_{\lambda}\ln R_{\lambda})/\sum \limits_{\lambda=1}^{3}\omega_{\lambda}\right] \tag{8}\]  
Since \(R_{\lambda}\) and \(\omega_{\lambda}\) are fuzzy numbers (\(\lambda=1,2,3\)), they cannot be calculated directly.