The time required for the liquid metal to enter the cavity to fill the cavity is called the filling time. The length of filling time depends on the size and complexity of the casting volume. For large and simple castings, the filling time is relatively long, and the filling time for complex and thin-walled castings is shorter. The filling time is closely related to the cross-sectional area of the gate or the width and thickness of the gate, and must be correctly determined.
2. Holding and opening time
When the liquid metal filling cavity is completely solidified, the duration of the injection under the action of the injection punch is called the holding time. The length of the holding time depends on the material and wall thickness of the casting.
After holding the pressure, the casting should be taken out. The time from the end of the injection to the opening of the die casting is called the opening time, and the opening time should be controlled accurately. The opening time is too short. Due to the low strength of the alloy, it may cause deformation when the casting is ejected and the self-pressing mold falls. However, if the opening time is too long, the casting temperature is too low, the shrinkage is large, and the core is drawn and the casting is ejected. The resistance is also big. Generally, the opening time is calculated according to the wall thickness of the casting 1 mm, and then it is adjusted for 3 seconds.