Quality problem solving procedure applied to a FPT Industrial production line. Brief overview on the plant, product and quality controls. Description of the 7 steps of Quality Maintenance (QM) and of the tools used to solve the quality issue coming from the manufacturing line. The case study starts from the FTQ analysis and proceeds with the application of the tools of the QM, including the PPA (Process Point Analysis), which is required to find the root cause of the problem. The goal of the entire procedure is to tend to zero-defects, resulting in time and cost benefit.