Die casting is frequently classified by the heat and pressure required to pump molten metal into the die casting mold. However, the metal parts production technique can also be classified according to the type of material. On the other hand, zinc die casting is the most frequent in terms of part strength. This article discusses die-casting with zinc, its applications, and comparisons to other materials.
Table of Contents
What is Zinc Die Casting?
Zinc die casting is a method that includes melting a zinc alloy and injecting it into a die casting mold. Zinc alloys are suitable for part manufacture due to their ductility, impact strength, and low melting point. Furthermore, the casting process takes place at a lower temperature due to the material’s low melting point. Therefore, it can also be called the “hot chamber die casting process”.
In addition, hot chamber technology improves mold durability compared to other materials compatible with die casting. And it reduces the time required for reworking and lowers costs.
Steps of the Zinc Die Casting Process
Typically, the zinc die casting process is also a hot chamber die casting process. The process varies depending on the part size and machine type. However, there is a common mechanism, as shown below:
Step 1: Prepare the Die
Clean the die-cast mold to remove any contaminants. After that, lubricate the die to improve the ejection of the cast part after cooling. The operator then needs to use high pressure to clamp the mold.
Step 2: Injection
Melt the zinc alloy and transfer it to the injection machine’s shot chamber. Remember that the shot chamber will be heated since zinc casting is a hot chamber die casting. After that, inject the molten zinc material into the die-cast mold under high pressure.
Step 3: Cooling and Ejection
Allow the zinc to cool in the die-cast mold to form the mold shape. Unclamp the mold to release the solid zinc casting from the die. It is important to note that, make sure the casting cools and solidifies before ejecting.
Step 4: Trimming
Trimming, like other finishing operations, involves the elimination of surplus metal caused by die casting errors. Trimming can be accomplished with a trim die, a saw, or other methods. It is important to note that, the trimmed zinc cast is recyclable and reusable.
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Zinc Alloys for Die Casting
There are various zinc alloys suitable for die casting. Each has unique characteristics. For example, Zamak 3 is a popular zinc alloy for die casting. This is because of its excellent dimensional stability and balance of physical and mechanical qualities. A list of zinc alloys appropriate for die casting includes:
Zamak 2
Zamak 2/Zinc Alloy 2 is the most durable and hard alloy in the Zamak series. As a result, it is suitable for casting pieces that require great structural integrity. Therefore, they are commonly used in the automotive and mechanical industries.
Zamak 3
Zamak 3/Zinc Alloy 3 is a common zinc alloy with excellent dimensional stability and casting properties. Aside from its physical and mechanical qualities, it is suitable for a variety of finishing processes. Such as painting, chromate treatments, and plating.
Zamak 7
Zamak 7/Zinc Alloy 7 is a modified Zamak 3. It is lower in magnesium and impurities than other members of the Zamak family. Because of its composition, the Zamak 7 is suitable for producing items that require good castability and surface polish. Aside from that, it is quite ductile.
Zamak 8
ZA-8, a zinc-aluminum alloy, has a higher aluminum concentration than other Zamak alloys. Unlike other ZA alloys, the ZA-8 is suitable for hot-chamber die casting.
ACuZinc5
ACuZinc5 is recognized for its hardness, lubricity, and creep resistance. It was researched and developed by General Motors, and it is suitable for producing parts with great structural integrity that would be used in hot temperatures.
EZAC
EZAC is another zinc alloy suitable for hot chamber die casting. It offers excellent creep resistance, high hardness, and yield strength.
ZA 27
ZA-27, based on its number, contains 27% aluminum. Consequently, it includes a higher level of aluminum than the Zamak family. Because of the aluminum component, it is more lightweight, sturdy, and long-lasting. As a result, it can also be used to create structurally sound components.
Yonglihao Machinery has many zinc alloys for casting and a thorough understanding of their applications. As a result, we can advise you on the most suitable material for your project.
Benefits of Zinc Die Casting
Although die casting works with a variety of materials, zinc alloy die casting is popular due to its mechanical qualities. In comparison to other alloys, it is stronger, tougher, firmer, and more cost-effective. The procedure has several advantages, which are listed below.
Easy Assembly
As with any other die casting process, the entire part is cast as a single unit. Therefore, it is easier to install.
High Precision with Thin Walls
Zinc alloys are stronger than other alloys suitable for die casting. As a result, design optimization that involves reducing wall thickness can be implemented. In comparison to materials like aluminum, zinc can maintain structural integrity in such situations. In addition, using less material lowers the cost of metal die casting.
Better Mechanical Properties
Zinc alloys offer an edge over aluminum and magnesium in terms of mechanical qualities like strength and durability. This makes them more suitable for use in parts that require high-strength materials. Other mechanical qualities include corrosion resistance, stiffness, and toughness.
Cast Complex Geometry
Zinc’s strong bearing and wear qualities make it appropriate for use as bushings in moving constructions. It is also suitable for producing parts with complex geometries. This is because of its ability to establish joints with other materials.
Longer Tool Life
Because zinc alloys are less abrasive and have a lower melting point. As a result, the service life of the dies used in zinc die casting is ten times longer than that of aluminum die casting dies. Therefore, there is less mold damage and the tool lasts longer. Furthermore, this lowers the cost of tooling when compared to alternative materials.
Faster Production
Zinc alloys have a low melting point and must be cast in a hot chamber under high pressure. Therefore, this increases the cycle rate more than other materials, such as aluminum.
In zinc die casting, zinc is injected directly into the die mold. This differs from aluminum die casting, which requires the aluminum to be melted in an external container before injection. Furthermore, the casting has a high solidification rate, which increases the quantity of components produced while lowering the cost of casting.
Various Finishing Options
There are various finish options available for die casting materials. The following are common finish options:
- Plating is useful for increasing the practical and aesthetic properties of die-cast zinc. Increased corrosion resistance and durability might be considered functional improvements.
- Because of the variety of colors available, powder coatings for die-cast zinc are used mostly for aesthetic reasons. Aside from that, it provides a long-lasting and homogeneous surface polish to the casted pieces.
- Painting serves both functional and aesthetic purposes. Because of the variety of colors available, they are primarily employed for practical purposes, similar to powder coating. Compared to powder coating, painting takes less time and has lower production costs.
In addition, other finishing choices for zinc casts include electroplating, mechanical plating, and anodizing. Each has its own set of characteristics that influence how the finished product is used.
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The Disadvantages of Zinc Die Casting
Zinc alloy die casting provides advantages in terms of strength and durability, but it also has downsides. The following are some of the material’s shortcomings.
Is Prone to Defects
The method has a fast filling rate and cools quickly. As a result, gas release may be delayed, leading to flaws such as pores. Furthermore, imperfections like pores and blisters degrade die casting quality. Aside from that, such castings should not be heat treated because it can cause damage.
Heavy Parts
Zinc die casting is more durable yet heavier than materials like aluminum. As a result, they are unsuitable for sections requiring lightweight construction. This is evident in the process’s decreased utilization in the aerospace sector.
Not Suitable for Small Batch Production
Die casting has a significant upfront investment cost. As a result, they are widely suitable in the mass manufacture of components. Because of the high expense of die casting, they are unsuitable for small-batch manufacture.
Applications for Zinc Die Cast Parts
Zinc die-cast pieces are used in a variety of industries. For example, their robustness makes them preferred in the automotive industry for interior and engine components. Here are a few applications for zinc die-cast parts:
Automotive Industry
Zinc castings are used to make a variety of car interior components. The material is preferred over aluminum because of its strength. Automotive zinc alloy castings include bearings, steering, and brake components. Due to its hardness and strength, the Zamak 2 zinc alloy is the most commonly used.
Electronics
Zinc alloy casting is also used to make components used in the manufacture of electronic devices. Such as energy regulators, toggle switches, wall clocks, and ceramic-encased resistors. Dimensional stability is relevant in this case. As a result, Zamak 3 alloy is best suited to the production of electrical components.
Home Appliances
Zinc casting is ideal for producing household items such as belts, furniture inserts, key chains, shoe buckles, door locks, and handles. Here, its strength and dimensional stability make it ideal for usage in home appliances.
Mechanical Sector
Zinc alloy casting can also be utilized to make engine parts for mechanical applications. Creep resistance and hardness are important features to consider here. As a result, the material is better suited than others like aluminum.
Conclusion
Zinc alloy die casting is the most frequent casting method for producing strong and durable components. If you need to cast zinc parts, you must understand the die casting process. Then, you need to outsource to a successful die casting supplier.
Yonglihao Machinery can provide customized zinc die casting services. We produce high tolerance and precision zinc parts with competitive prices and fast delivery time. Contact us for a quick quote. Then we can bring your needs to fruition quickly.