Influence of Overflow Connecting Channel Cross-Section Design on Selected Parameters of High Pressure Die Casting

High pressure die casting technology (HPDC) is a method enabling the production of shape-complex casts with good mechanical properties, with high repeatability of production within narrow tolerance limits. However, the casts show, to some extent, basic porosity, which may reduce their mechanical and qualitative properties. One of the main areas to focus on in order to reduce the porosity of casts is the correct design and structure of the gating and overflow system. Submitted article is devoted to the assessment of the connecting channel cross-section design for connecting the overflows to the cast on selected parameters of the casting process. Five different cross-section designs of connecting channels are considered, enabling the removal of gases and vapors from the volume during the molding. The connecting channels are designed with a constant width g = 10mm and variable height h1 =1.50 mm, h2 = 1.25 mm, h3 = 1.00 mm, h4 = 0.75 mm and h5 = 0.6 mm. The primary monitored parameter is the gas entrapment in selected points of the cast. The following is an evaluation of the pressure conditions change in the mold cavity at the end of the filling mode and local overheating of the mold material just below the surface of the mold face. With regard to the monitored parameters, based on the performed analyzes, the most suitable design solution of the connecting channel is assessed and recommendations for the design and structure of the overflows and their connection to the cast are derived.