Zinc Alloy's Capacity to Fill TimeThe Die Casting Process and the Regulation of the Temperature of the Die Casting

It is essential to have precise control over the temperature of the die casting surface in order to produce high-quality parts made of zinc alloy

It is essential to have precise control over the temperature of the die casting surface in order to produce high-quality parts made of zinc alloy. The filling time of the zinc alloy die casting process as well as the temperature control of the die casting mold are both topics that are covered in this guide.




Temperature Regulation of the Die Casting Mold Along with the Filling Time of the Zinc Alloy Die Casting Process

1. Filling Time T= (q/v charging Ag)
Where t is the filling time in seconds, q is the metal volume in cubic meters, V is the filling speed in meters per second, and ag is the cross-sectional area of the inner gate in square centimeters.

When producing die castings, China die casting mold is necessary for liquid metal to fill the mold cavity as quickly as possible so that the finished product has a clear contour and high-quality surface. The filling time for zinc alloy die cast workpieces is between 6 and 40 milliseconds, as determined by the characteristics of the workpiece. When it comes to mechanical workpieces or those that need electroplating, the filling time is less than 20 milliseconds, and the workpiece that needs to be painted takes less than 40 milliseconds.

2. The length of time the pressure is maintained
The injection cylinder must continue to operate after the metal liquid has filled the mold cavity. This ensures that the punch continues to apply pressure to the metal, which in turn ensures that the metal liquid crystallizes under pressure. Additionally, the volume shrinkage of the die casting caused by the solidification process must be continuously compensated for by the liquid. This will ultimately result in the production of a casting that has a dense structure. One strand takes more than 0.5 seconds to solidify, and the holding time is calculated based on the wall thickness of the casting as well as the solidification time at the inner gate. If there are a large number of voids and cavities found in the center of the nozzle material, this is an indication that the pressure maintaining time was insufficient and that the hammer return occurred too soon. It's possible that the pressure holding pressure isn't high enough if there are voids and cavities in the wall thickness of the casting or close to the inner gate. When the holding time is insufficient, the surface of the pressed castings is frequently not attractive, and the machine process parameters need to be adjusted to compensate for this.

3. the length of time mold can be kept

After the injection has been finished, the liquid metal that was inside the mold cavity will start to cool and solidify. In order to prevent the ejection from becoming misshapen or damaged, the casting must be removed only after the temperature of the casting has been lowered to a predetermined level and the casting has achieved a predetermined level of mechanical strength. The duration of time between the conclusion of the pressure holding time and the opening of the mold in order to eject the casting is referred to as the mold retention time. If the ejection time is too short, the castings are prone to deformation, cracking, and blistering on the surface; if the mold retention time is too long, the mold holding force that is formed due to the solidification shrinkage force will increase, resulting in difficulties in core pulling and ejection, which can easily cause cracking of the castings; and if the ejection time is too short, the mold holding force that is formed due to the solidification shrinkage force will increase. It can take anywhere from 5 to 10 seconds, depending on the size of the casting, the wall thickness, the shape, and the temperature of the mold. The degree to which the die-casting has been deformed can also be evaluated to determine whether the recommended amount of mold retention time has been met.

4. Mold temperature
The temperature of the China die casting mold is a crucial factor in determining the overall quality of die castings. The temperature of the mold will shift throughout the process of die casting.

Die temperature range of die casting mold:160 – 220 ℃

Temperature range for electroplating castings: 180–220 degrees Celsius

Because the temperature of the mold is too low, the liquid metal begins to solidify too early in the process of filling the mold cavity. This makes it easy for defects such as surface return cold lines and flow marks to appear in the finished product. When the temperature of the mold is too high, it is easy for the mold to stick, and the surrounding workpieces will weld together with the mold. Because of the high mold temperature, the casting will cool slowly, and the grain will be coarse. This makes it easy to produce shrinkage and porosity, which ultimately leads to a reduction in the material's mechanical properties.

The spraying effect of the coating has a direct relationship to the temperature of the mold.

The temperature of the mold has a close connection to both the casting cycle and the amount of cooling water that is used. The setting of the cooling water circuit and the adjustment of the cooling water volume are the means by which the temperature balance of the die-casting mold can be controlled.

During the process of production, it is important to pay attention to maintaining a consistent die casting cycle in order to maintain the temperature of China die casting mold and ensure that it does not fluctuate. 

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