Failure Mode and Effects Analysis (FMEA) can be translated into Turkish as 'Failure Mode and Effects Analysis'. FMEA is a method used to systematically determine and analyze the impact of errors on customers (internal and external) in designs or processes; It is applied when significant errors are detected when changes are made and a new application is started.
FMEA is a risk analysis and its history has been briefly as follows:
It was developed by the US Army (MIL-P-1629) in 1949 as a reliability evaluation technique.
It was used in NASA's Lunar Landing Project (APOLLO) in the 1960s.
It was used in the aviation and aircraft industry in America in the 1970s.
In 1975, the first industrial applications began in Japan (NEC company).
In 1980, Ford Motor Company started to implement it and requested this practice from all its sub-industries.
Benefits of FMEA
It encourages teamwork and develops team spirit.
It helps to create a brainstorming environment and become a culture in the company.
It helps manufacturing companies to fully analyze the entire process from input control to shipping.
If done effectively; It is a unique record that can be used as a resource in problem solving activities, new staff orientation, and improvement practices.
Hazards in the machining industry can be diversified into operator-related hazards and hazards arising from machine and system malfunctions. In this study, risks that may affect product quality will be evaluated.
The risk priority number (RÖS) before applying the FMEA method is compared with the number (RÖS) after it is applied, and the results aim to minimize all risks.
How is FMEA applied?
1. Identified errors are scored according to standard tables out of 10 points under three headings.
Severity: Evaluates the consequences of error effects on the customer.
Probability: The probability that an error will occur.
Detectability: It is the probability of detecting the defect before it reaches the customer (leaves the production line).
2. Risk Priority Number is determined. This number is obtained by multiplying the scores in the three headings mentioned above.
RÖS = (Probability) x (Severity) x (Detectability)
3. Error solutions are sorted according to the risk priority number. The following criteria can be used when making this ranking.
If RÖS < 40, there is no need to take any precautions.
If 40 < RÖS < 100, it is not mandatory to take into consideration, but it is useful.
If RÖS is >100, precautions should be taken.
If the violence value is 9 points or above; Precautions must be taken regardless of the risk priority number.
As a result of the examination of Ünsal Makina's machining operations (CNC Turning/Milling), 14 main error types affecting product quality were identified. Since 9 of these values were ≥ 100, that is, exceeded the threshold value, it was decided that they should be considered as a priority. However, after the study, it is seen that dangers and risks can be eliminated when the precautions and actions to be taken are determined.
The problems encountered are generally; Human errors (inaccurate measurement, carelessness, lack of training), incidental maintenance such as not being able to take the desired measurements as a result of deterioration of machine bearing and wedge adjustment, insufficiency of coolant, incorrect software by inexperienced people, other factors (working in an excessively noisy environment, insufficient lighting, etc.). are factors. Such problems detected before applying the FMEA method; It was observed that there were decreases in the problems compared to the situation after the method was applied. Thus, the fact that the FMEA method gives accurate and healthy results has shown that the method is preferable.
FMEA; It is one of the important techniques used in the quality improvement process that helps prepare detailed control plans for errors. However, since quality improvement is a continuous process, monitoring and supporting the operations for which control measures are taken with the FMEA technique with Statistical Process Control techniques will be more beneficial to companies.
Source:
Şaşal A. (January, 2021), “What is Failure Mode and Effect Analysis FMEA (Failure Mode and Effect Analysis)? "What are their contributions to the sector?", p.28-30, Cooling World
Uçum M. (2020) ''Risk Analysis Applications and Comparison with Fine-Kinney and Fmea Methods on CNC and Milling Machines''
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