The pressure casting method changes depending on the mold temperature, the casting temperature, the injection pressure, the injection speed, the mold surface roughness, the mold design, the alloy type, the application of a vacuum to the mold cavity, and many similar parameters. This study investigated filling analyses on the Al6061 alloy with and without vacuum injection parameters applied to the mold cavity during the pressure casting process. The filling analysis, pressure drops, and velocity vectors with and without vacuum conditions were compared. In the vacuum casting process, it was observed that the filling process was faster under the effect of a vacuum. In the casting process without a vacuum, the filling analysis time was calculated to be 1.2 s. In the filling analysis performed by assuming the vacuum pressure to be 500 Pa, it was completed in up to 0.95 s. In the pressure casting process, the vacuum filling process was completed in a shorter time compared to the filling process without a vacuum, and the casting process saved 21% in terms of time. Higher mold temperatures were observed in the vacuum casting process. An 8% higher heat transfer was calculated for the vacuum casting process.