Die casting is generally categorized by the heat and pressure required to inject molten metal into the die casting mold. However, part manufacturing processes can also be categorized by material type, with zinc die casting being the most common in terms of part strength.
Zinc die casting is a process that involves melting zinc alloy (hence the name zinc die casting) and injecting it into an already prepared die casting mold.
Zinc alloys are suitable for component manufacturing due to their ductility, impact strength and low melting point. Furthermore, the casting process takes place at lower temperatures due to the low melting point of the material. Hence the name "Hot Chamber Die Casting Process".
Additionally, being a hot-chamber process also increases tool life, time required for tool changes, and reduces costs compared to other die-casting-compatible materials.
Steps of Zinc Die Casting Process
Generally speaking, zinc alloy die casting is a hot chamber die casting process. While the process changes based on part size and machine type, there is a general mechanism as follows:
Step #1: Prepare the Mold
Clean die casting molds to remove impurities. Then, lubricate the mold for better release of the casting after cooling. Finish the first step by clamping the mold with high pressure.
Step #2: Inject
Melt the zinc alloy and pour it into the injection chamber of the injection machine. Note that the injection chamber will be very hot as zinc castings are hot chamber die castings. Then, the molten zinc material is injected into the die casting mold under high pressure.
Step #3: Cool and Pop Out
The zinc is allowed to cool in the die casting mold to form the mold shape. The mold is released and the solid zinc casting is ejected from the mould.
Note: Make sure the casting is cooled and solidified before demolding.
Step #4: Trim
Along with other finishing processes, trimming involves removing excess metal caused by die casting defects. Trimming can be done using trimming dies, saws, or other procedures.
NOTE: Trimmed zinc castings are recyclable and reusable.
Advantages of Zinc Die Casting
Zinc die casting
Although die casting is compatible with many materials, zinc alloy die casting is popular for its mechanical properties. For example, it is strong, tough, robust and cost-effective compared to other alloys. Here are some advantages of the process.
easy to assemble
As with any other die casting process, the entire part is cast as a single piece. Therefore, assembly is reduced.
Thin Wall High Precision
Zinc alloys are stronger than other alloys compatible with die casting. Therefore, design optimizations requiring reduced wall thickness can be implemented. Zinc still exhibits structural integrity in this case compared to materials such as aluminum. In addition, lower material usage reduces die casting costs.
better mechanical properties
Zinc alloys are superior to aluminum and magnesium in terms of mechanical properties such as strength and durability. This further improves their use in components requiring high-strength materials. Other mechanical properties include corrosion resistance, robustness and toughness.
Cast complex geometries
Zinc's excellent load-bearing and wear-resistant properties make it suitable for use as bushings for moving structures. Furthermore, due to its ability to form joints with other materials, it is suitable for making parts with complex geometries.
longer tool life
Because zinc alloys are less abrasive and have a lower melting point, the die life for zinc die casting is about ten times that of aluminum die casting dies. As a result, tool damage is reduced and tool life is increased. Furthermore, this reduces processing costs compared to other materials.
faster production
Zinc alloys have a low melting point and require a hot chamber die casting process during high pressure injection. This will increase cycle rates over other materials such as aluminum (zinc alloy die castings have 150-200% higher cycle rates than aluminum).
In zinc die casting, the zinc is injected directly into the mold. This differs from aluminum die casting, which requires the aluminum to be melted in an outer container prior to injection. In addition, castings have a high solidification rate, which further increases the number of parts produced and reduces casting costs.
