Background: The Plan-do-check-act (PDCA) cycle methodology for a continuous improvement project implementation aims for the internal logistics upgrade, which is especially important in the industrial context of a component manufacturing company for the automotive sector. Objectives: The goal is to quantify the gains from waste reduction based on the usage of the PDCA cycle as a tool in the implementation and optimisation of a milk run in an assembly line of a company in the automotive sector by determining the optimal cycle time of supply and the standardisation of the logistic supply process and the materials’ flow. Methods/Approach: The research was conducted through observation and data collection in loco, involving two main phases: planning and implementation. According to the phases of the PDCA cycle, the process was analysed, and tools such as the SIPOC matrix, process stratification, 5S, and visual management were implemented. Results: Using Lean tools, it was possible to reduce waste by establishing concise flows and defining a supply pattern, which resulted in a reduction of movements. The transportation waste was reduced by fixing the position of more than half of the materials in the logistic trailers. The developed Excel simulator provided the logistic train’s optimal cycle time. Conclusions: The assembly line supplied by milk-run was fundamental to highlight a range of improvements in the process of internal supply, such as better integration of stock management systems, greater application of quality, or the adoption of better communication systems between the different areas and employees.

Reverse logistics lacks an exhaustive study on its impact on supply chain management and its integration with Continuous Improvement. Through a survey submitted to companies in the northern region of Portugal, this study shows how reverse logistics and Continuous Improvement have been considered and applied by companies. Microsoft Forms was used to properly administer the survey, which was submitted to 80 companies to collect data from a convenience sample. Yet, it was only possible to validate 60 responses, which, for a confidence level of 90%, represents a margin of error of 10.62%. Regarding the data analysis, descriptive statistics was used to present the main results. Nonetheless, normality tests were also carried out to understand if parametric or non-parametric methods could be applied to analyze the number of weekly hours dedicated to the reverse logistics process. The results show that most companies have informal reverse logistic management, being the biggest companies or those with higher turnover who apply a formal process. The main activity performed in the reverse logistics process is resale and remanufacture. For the interviewed companies, the main reason for having a reverse logistics process is to reduce materials’ or products’ costs and simultaneously increase profits by reusing products or materials. Regarding the factors that impact the performance of RL systems, the non-uniformity of the returned product is the most demandable. The most widely used continuous improvement tools in reverse logistics are 5S and the Kaizen. In sum, despite the benefits of improving customer satisfaction, reverse logistics should also be considered in enhancing sustainability and complying with regulations.