According to many profitability experts, the added value of the company is in the production and assembly line. Therefore, the issues that challenge this profitability are essential. It is one of the most critical factors in fixture stoppage, neglecting it leads to reduced profits, quality, demand, and loss of customers. The present study aimed to "investigate and analyze the pattern of the reduction or elimination of production Stoppage in Renault body fixtures". In order to achieve this goal, two fuzzy and FTA approaches have been used. Fractures and their cause were determined, and then occurrence and control probability factors were calculated using fuzzy fault tree analysis. In order to apply the method, the necessary data were collected using a questionnaire and a survey of experts, and then fuzzy FTA methods were performed. Wang (2014) model was selected as the reference model. This model states that the fuzzy numerical method is proposed to eliminate the defects of the failure analysis and its effects in such a way that it integrates the degree of similarity of fuzzy numbers and probability theory. This study referred to the database of Pars Khodro Company and reviewed the relevant data during 2016 and 2017 to determine the effective factors in causing the failure of Renault body fixture, According to data reported for 500 Renault body fixture stoppage, the main factors extracted were "pneumatic fixture circuit failure", "copper backbar failure", "pin failure", "locator failure", "head clamp failure", "compressor air pressure drop", "sensor" and "cylinder or power clamp". "Sensor" and "cylinder and power clamp" were reported as latent factors. After determining the main factors, sub-factors for each of the main factors were extracted, and the fault tree was drawn.
