This research focuses on modelling and optimization of production of aluminium 360 alloy for six process parameters used in irrigation pipe couplings. Aluminium 360 alloy was selected for its favourable combination of corrosion resistance, pressure tightness and mechanical strength required in agricultural water distribution systems. Six die-casting process parameters, pouring temperature (PT), mold temperature (MT), ejection temperature (ET), shot chamber temperature (SCT), intensification pressure (IP) and degassing time (DT), were investigated as potential factors that have a great influence on porosity, leak-pressure, ultimate tensile strength (UTS), elongation and casting yield, and the quality of irrigation pipe couplings. The Taguchi method for robust parameter design was employed to systematically investigate the effects of six die-casting process parameters on five response variables. This approach was selected because it enables efficient exploration of multiple factors with a minimal number of experimental runs while providing robust optimization that minimizes sensitivity to noise factors. The developed predicted models for all five responses were validated by comparing the experimental and predicted values obtained from 16 experimental runs. The coefficient of determination (R²), root-mean-square error (RMSE) and mean absolute percentage error (MAPE) were used to assess the agreement between the experimental and predicted responses. The results indicate that the leak-pressure model generated an R² of 0.6593, RMSE of 0.2734 and MAPE of 6.02%; the porosity model yielded an R² of 0.6168, RMSE of 0.2430 and MAPE of 9.45%; the UTS model produced an R² of 0.6031, RMSE of 9.2058 and MAPE of 2.53%. The elongation model recorded the highest R² value of 0.7945 with an RMSE of 0.3925 and MAPE of 8.61%, indicating the strongest coefficient-of-determination relationship among the five responses; the model therefore demonstrates a relatively strong predictive relationship for elongation. The main objective of this study is to identify optimal parameter settings that simultaneously maximize mechanical performance, pressure integrity, and process robustness for Aluminium 360 four-way pipe couplings with a focus on porosity minimization. Five models were developed with analysis of variance, while the regression correlation analysis between porosity and leak-pressure was examined taking porosity as the independent variable and leak-pressure as the dependent variable. The result showed that the coefficient of determination was approximately 20.16% of variation in leak-pressure with a negative slope of −0.5358, indicating an inverse relationship between porosity and leak-pressure; however, this relationship was not statistically significant at the 5% level (p ≈ 0.08). The study showed that the optimal setting of the process parameters was obtained at experimental run 15, yielding the least cast porosity at DT = 15 min, PT = 705 °C, MT = 250 °C, IP = 60 MPa, ET = 200 °C, SCT = 90 °C, with corresponding responses at leak-pressure (3.92 MPa), cast yield (80.68%), UTS (319 MPa), elongation (5.57%).
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