Today's manufacturing industry, especially in the context of the metals industry, is constantly evolving towards ever more advanced technologies and efficient production practices. In this context, machinery modernization is becoming a key element in improving manufacturing processes. This article focuses on analysing the impact of machinery modernization on casting quality, using selected quality management tools. The article presents an analysis of the effects of the implementation of modern technology, automatic casting machines, on the quality of castings production. Using quality tools such as the Ishikawa diagram, Pareto-Lorenz and the FMEA method, the main causes of casting nonconformities, the frequency of occurrence of these nonconformities and the risks associated with them were identified for periods before and after the implementation of machine park modernization. The measurable benefits associated with the introduction of modern foundry technology in terms of improved casting quality were showed. Using quality tools, the quality improvement achieved was determined indirectly, while the level of improvement in casting quality after the modernization of the machine park was showed directly using the defect rate. It was also shown that, despite an increase in production efficiency and the level of quality of the manufactured products, the introduction of the new technology generated new quality challenges in the context of maintaining the stability of the casting process parameters as a result of a jump in productivity levels. The paper highlights the need to balance production efficiency with attention to casting quality, which was an important issue for the foundry studied.