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Traditional failure mode and effects analysis (FMEA) determines the risk priority number by finding the multiplication of factor scores that are converted from the probability or degree of problem occurrence without considering the relative importance of factors. This study applies fuzzy theory to eliminate the conversion debate by directly evaluating the linguistic assessment of factors, and uses grey theory to obtain risk priority number by assigning relative weighting coefficient without any utility function. Results of the illustrative example show that concurrent application of fuzzy method and grey theory can solve the problems that have arisen from conventional FMEA, and can efficiently discover the potential failure modes and effects. Indicates that, as a result, the stability of product and process can be assured.

Conventional FMEA determines a risk priority number by multiplying the scores of three factors. However, the scores are obtained from subjective linguistic assessment, and the relative importance of factors is not considered. To improve the effectiveness, this study applies the grey theory to the failure mode and effects analysis. The results show that grey theory is much easier and more unbiased than traditional FMEA, and it can enhance product reliability and process stability by discovering potential problems during the stages of the product design and process planning.

Proposes a new formulation for allocating process tolerances. The major contribution of the model is to assign tolerances with maximization of the conformance rate of the entire process. The cumulative standard normal probability is used to estimate the scrap rate of each operation with respect to the machining accuracy of equipment, therefore, the design engineers are able to predict the failure rate before production. Results of comparison with other methods indicate that the proposed model can cost‐effectively assign tolerances.

The purpose of this paper is to design a low-cost stress bimorph RF-MEMS switch which is the desired transmission area application.

The bimorph structure of the low-temperature plasma-enhanced chemical vapor deposition (PECVD) of thermal oxide and gold are utilized to create the vibrating membrane. The effects of process conditions of low-temperature oxide deposited using the PECVD technique enable stress-free deposition of the key structural layer.

Scanning electron microscope images of the RF micro-switch confirms negligible stress in the released structure. The RF performances of this device exhibit isolation around 43 dB of up to 50 GHz in the OFF-state position and an insertion loss of less than 0.18 dB in the ON-state.

The finite element method results show good isolation of 43 dB and less insertion loss of 0.18 dB.