<p>Increasingly, in modern foundries, the application of precise feeders helps designers to prevent porosity in nodular graphite iron castings, ensuring the structural integrity and mechanical performance required by the client. However, at the same time, the metallurgical aspect can be affected by the use of these feeders. Indeed, the presence of abnormal or even degenerated graphite is often found in the surrounding area of sleeves and mini-risers, leading to a loss of the mechanical properties to the point of scraping the casting. The aim of this study was to evaluate the effect of exothermic sleeves, both in terms of graphite morphology in the casting skin, and of the presence of fish-eye defect. The investigation was carried out by comparing different types of feeders, such as insert sleeves and mini-risers. Especially, the graphitic structure was analysed in the presence of innovative fluorine-free exothermic material and compared with classical exothermic materials available on the market.</p><p>For the implementation of the project, a model plate was designed with cubes featuring different thermal moduli calculated by using a commercial simulation software: 1.6 cm, 1.9 cm, and 2.3 cm. The experimental test was carried out in a real foundry by casting standard ductile iron grade EN-GJS-500-7. The entire melting process was monitored by using a commercial adaptive metallurgical process control system based on thermal analysis. It was found that fluorine-free exothermic feeders can guarantee the integrity of casting skin as well as complete nodularity below the feeder neck and immediately close to its fracture surface.</p>