Abstract The aim of the study was to indicate the reasons for non-compliance of aluminium rim castings and, using quality management instruments (Pareto-Lorenzo diagram and 5WHy method?), elimination or reduction of non-compliant products. The object of the research was an aluminium rim, while the diagnostic process of the object of the research was based on the quality control of the chemical composition of the casting, the control of mechanical properties and the control of the continuity of the material structure by radiographic and microscopic methods. On the basis of the research carried out, it was found that a sensitive casting area is the front edge of the rim rim - a significant number of porosity clusters were identified in this area. The reason for their occurrence was also specified - too rapid flooding of moulds, which resulted in gassing of the alloy. The identified cause had its origins in human resources mismanagement, namely the lack of training of the newly recruited employee. So far, the company has not carried out analyses of quality problems with the use of a sequential quality management methodology, so the implemented corrective actions have not always led to the full achievement of quality objectives. The presented sequential method, which is a combination of diagnostic and control tests and quality management instruments, is a universal way to monitor the level of quality of products and to quickly correct nonconformities.