Application of Six Sigma DMAIC approach for scrap management in End-of-Line Testing at Stellantis Powertrain Plant

The Project developed during an internship in Quality Engineering within a Powertrain Plant of Stellantis, focuses on problem-solving activities in the field of Product Quality. It is based on the Six Sigma approach to reduce the scrap rate at the End of Line test. The activity performed is pivotal in the current period, where within the OEMs’ environment the focus is on the continuous improvement of the production lines and innovation by aiming at zero waste and zero errors produced. In this condition, every reduction in terms of scraps rate percentages is essential and has an important effect on production efficiency and cost saving. The approach followed, to find the root cause and eliminate a particular voice of failure from the Pareto chart of the Plant, is the Six Sigma DMAIC. This is based on 5 steps and is designed to detect the root cause of the identified issue and reduce the variability in the process results, leading to an improved process. The first step, Define, focuses on providing a clear problem statement, utilizing the 5W1H (What, Where, When, Who, Which, How) tool. The next phase, Measure, involves identifying and analysing the required KPIs, as well as the physical measurements of the items affected by the problem. These are represented by the KPI to monitor the product quality (scrap management) and the End of Line test measures. Within the Analyse phase, different statistical tools and principles are employed to identify all components related to the problem’s occurrence, ending with the identification of its root cause. This represents the primary goal of the project and is achieved through the systematic application of statistical and problem-solving tools such as the Ishikawa Diagram and the 5-Whys. The fourth step, Improve, defines and implements corrective actions based on the clarified problem’s origin, and finally, the Control phase ensures the improvement process is sustained by monitoring the problem’s recurrence and assessing the effectiveness of the corrective actions. As a result of this Six Sigma project, the scrap rate for the analysed voice of failure was reduced to zero, leading to an improvement in production efficiency and consequently saving production costs. This thesis demonstrates the entire problem-solving process through the application of the Six Sigma methodology and explains, by approaching a real case study, how the project’s final objective was successfully achieved.