<p>The High Pressure Die Casting (HPDC) represents a viable manufacturing process to achieve a high complexity of the final part while keeping the cycle time sufficiently short. The process design is not trivial and the identification of the causes leading to defects (porosity, flashes) on the cast part as well as premature deterioration of the die surfaces is extremely complex. The present work investigates the manufacturing of aluminium brackets via HPDC from a holistic perspective: industrial tests on an OMS550 press revealed the occurrence of flash, metallization, and localized die wear, already within the very first part of life. Due to the complexity of the process, the numerical approach was adopted and the industrial process was reproduced using the commercial code CASTLE to identify what determined the occurrence of the abovementioned defects in the final cast part. The numerical approach allowed to identify the imbalance of the thermal gradient (within the single die and between the fixed and movable die) and a non-perfect flow as the main responsible for the occurrence of defects (flashes and porosity in the brackets). Under the premise of adding limited by effective and strategic modification of the die cavity, a constriction in the runners’ cross section was designed close to the ingates to choke the metal flow and eliminate the precursors of possible defects in the cast part. The experimental trials carried out adopting the modified geometry of the die cavity validated the proposed solution: not only a dramatic drop in the occurrence of defects was recorded (flashes were almost absent), but the quality of the cast part (presence of porosity) was remarkably improved.</p>