Zinc die casting and aluminum die casting are two common metal die casting process, used to manufacture different types of parts and products, and has a wide range of applications in industrial production. This article will discuss in detail they have some significant differences in material properties, application areas and process parameters.
What is die casting?
Die casting is a kind of metal casting process that uses high pressure to force the metal melting pressure into the complex shape of the metal mold so that the metal solution under high pressure solidification molding is a kind of precision casting method. Die casting molds are usually machined from stronger alloys.
Zinc die casting and aluminum die casting process principle and process is similar, zinc die casting refers to the zinc alloy is heated to the liquid state, and then injected into the mold through high pressure, after cooling to get the required shape of the parts. Aluminum die casting refers to the aluminum alloy is heated to liquid state, and then injected into the mold through high pressure, after cooling to get the desired shape of the parts.
The differences between zinc die casting and aluminum die casting
Material Characteristics
Zinc Alloy
- Zinc alloys have a density of about 6.7-7.3 g/cm³, which is high compared to aluminum alloys.
- It has good flowability and plasticity.
- High strength and corrosion resistance, more suitable for projects with harsh environmental conditions.
- Lower melting point, easy to process and mold, more suitable for hot room process.
- Relatively poor thermal conductivity, usually used in applications where thermal conductivity is not required.
Aluminum Alloys
- Aluminum alloys have a relatively low density of about 2.5-2.9 g/cm³.
- It has high strength and is lightweight.
- Corrosion and wear resistance.
- Has excellent thermal conductivity and is suitable for applications requiring high thermal conductivity.
Processing Properties
Melting Temperature
- Zinc alloys have a relatively low melting temperature of approximately 419-455°C, which facilitates energy control and processing.
- Aluminum alloys have a melting temperature of approximately 660-660°C, which is higher than zinc alloys and requires higher heating energy.
Flowability
- Zinc alloys have good flowability and are capable of filling complex shaped mold cavities.
- Aluminum alloys are less fluid in the liquid state and require higher pressure to fill more complex molds.
Solidification shrinkage
- Zinc alloys have a solidification shrinkage of approximately 0.3-0.6%. The lower shrinkage helps to minimize shrinkage holes and shrink marks.
- Aluminum alloys have a solidification shrinkage of approximately 1.2-2.5%, and the relatively high shrinkage may result in more shrinkage holes and shrink marks.
Surface quality and finish
- Zinc die castings usually have a good surface finish because zinc alloys develop a smooth surface during solidification.
- However, the surface of zinc alloys may have some small air holes or tiny imperfections, which may require post-processing to repair.
- Aluminum die castings also typically have a better surface finish but may have a slightly rougher surface compared to zinc.
- Aluminum has a relatively fast solidification process, which may result in some porosity and inclusions.
Both types of castings can be finished by spraying, plating (electroplating or chemical plating), polishing sanding, and anodizing. Polishing and sanding is a common surface treatment used to remove porosity, imperfections, and roughness from the surface of die castings to achieve a higher surface quality.
Cost
Raw material cost
- Zinc alloy has a higher raw material cost than aluminum alloy. Zinc is a rare metal that is relatively expensive to produce and purchase, so raw material costs for zinc alloys are typically higher.
- Aluminum alloys have lower raw material costs. Aluminum is a metal abundant in the earth’s crust and is relatively inexpensive to produce and purchase, so raw material costs for aluminum alloys are typically more economical.
Equipment Investment
- Zinc die casting typically requires more corrosion-resistant equipment because zinc alloys are more corrosive to equipment in the molten state. Such equipment requires the use of zinc corrosion-resistant materials, which relatively increases the investment cost of the equipment.
- Aluminum die casting equipment investment is relatively low, because aluminum alloy corrosive smaller, generally commonly used die casting equipment can meet the production demand, and equipment investment is more economical.
Process complexity
- Zinc die casting usually in the solidification process will form a relatively smooth surface, relatively speaking, the complexity of its post-processing technology is low, and can save a certain amount of cost.
- Aluminum die casting solidification process is relatively fast, may lead to some air holes and inclusions, so after treatment process may be relatively complex, need more cost investment.
Environmental Protection and Sustainability
- Recycling rate
Zinc alloys have a high recycling rate. Due to the relatively simple process of recycling and reusing zinc, used zinc alloys can be easily recycled and reused in the production of new zinc alloy products, resulting in high recycling rates. Aluminum alloy also has a high recycling rate. The recycling and reuse processes for aluminum are relatively mature and can be efficiently recycled and remanufactured into new aluminum alloy products.
- Resource Sustainability
Zinc is a finite and rare metal with relatively low resource sustainability. As global demand for zinc increases, zinc ore resources will diminish, making zinc alloys challenging in terms of resource sustainability.
Aluminum is an abundant metal in the earth’s crust and has a high level of resource sustainability. The production of aluminum alloys is largely dependent on aluminum ore resources, which are relatively abundant and conducive to long-term sustainable use.
- Environmental impacts
The production process of zinc alloys generates relatively little carbon dioxide emissions, which contributes to the reduction of greenhouse gas emissions and has a relatively low environmental impact.
The production of aluminum alloys involves high-temperature melting and energy-intensive electrolysis, and therefore the production process may generate more carbon dioxide emissions.
Design Considerations and Limitations
- Wall thickness
Zinc has better liquid flow and therefore thinner wall thicknesses can be achieved, typically 0.5mm or thinner.
Aluminum has slightly less liquid flow than zinc, so in some cases, greater wall thicknesses are required. Typically, wall thicknesses for aluminum die casting range from 1mm to 5mm.
- Structural design
Zinc die casting: Due to the liquid flow of zinc, more complex structural designs can be realized, including thin walls, details, and complex geometries.
Aluminum die casting: Aluminum has slightly less liquid flow and therefore requires more attention when designing complex structures. While complex shapes can still be achieved, some additional design optimization and process adjustments may be required.
- Shape complexity
Zinc die casting: For highly complex products, more detailed surface textures and geometries can be achieved.
Aluminum die casting: While complex shapes can also be achieved, more cooling time and flow control may be required relative to zinc to avoid defects.
- Process Limitations
Zinc die casting and aluminum die casting: Both die casting processes require consideration of liquid metal flow and cooling processes to avoid the creation of shrinkage, bubbles and other defects. Therefore, flow channels and cooling systems need to be rationalized in the design.
- Production batch
Zinc die casting and aluminum die casting: For small production runs or customized products, both processes work well. However, for high-volume production, aluminum die casting may be more cost-effective due to lower raw material costs.
Advantages of zinc casting and aluminum casting
Advantages of zinc castings
Excellent fluidity: Zinc alloys have excellent fluidity, making them suitable for complex shapes and thin-walled parts. This allows zinc castings to achieve finer designs and details.
Good surface treatment properties: Zinc castings can be easily subjected to a variety of surface treatments such as electroplating, painting, anodizing, etc. to achieve different appearance and performance requirements.
Good corrosion resistance: Zinc alloy has excellent corrosion resistance, enabling zinc castings to maintain a long service life in wet or corrosive environments.
Low melting point: Zinc has a relatively low melting point, which makes the melting and molding process of zinc castings relatively simple, which is conducive to reducing energy consumption and production costs.
Recyclability: Zinc can be recycled and reused, contributing to environmental friendliness and sustainability.
Advantages of aluminum castings
Lightweight design: Aluminum is a lightweight metal with a high strength-to-weight ratio, making it suitable for part designs that require weight reduction. Aluminum castings are widely used for lightweight design in automotive, aerospace and other fields.
Excellent strength and rigidity: Aluminum alloys have good strength and rigidity at room temperature, which makes aluminum castings perform well when dealing with static and dynamic loads.
Good thermal conductivity: Aluminum has excellent thermal conductivity, which makes aluminum castings perform well in heat dissipation and conduction, and is suitable for application scenarios that require efficient heat dissipation.
Good Surface Finishing Characteristics: Similar to zinc castings, aluminum castings can be given a variety of surface finishes to improve corrosion resistance and appearance.
Recyclability: Aluminum is a recyclable material with a high recycling rate, which is conducive to saving resources and reducing environmental impact.
Industry Applications
Zinc castings
- Automotive Industry
As a new type of alloy material, zinc alloy die casting is widely used in all aspects of automobile manufacturing due to its lightweight, high strength, good electrical conductivity, and other characteristics. For example, the automobile engine, transmission system, steering wheel, door handle, seat accessories, and other parts, use zinc alloy die casting to replace the previous steel or aluminum alloy structural parts, which can greatly reduce the weight of the car and fuel consumption, improve the safety and service life of the car.
- Electronic industry
Zinc alloy die casting is also widely used in the electronics industry. Because zinc alloy die casting has good conductivity and dimensional stability, is used in power adapters, laser printers, copiers, scanners, and other equipment manufacturing, but also can make TV shells, audio, and other appearance parts.
- Communication industry
Zinc alloy die castings are also widely used in the communications industry. For example, cell phones, tablet computers, e-books, and other electronic products shells, and parts are mostly used for zinc alloy die casting for production. Zinc alloy die casting can not only improve the appearance quality and expressive force of the product but also can achieve lighter, thinner, smaller design requirements.
- Household goods industry
In the household goods industry, zinc alloy die casting also has many applications. Such as lamps and lanterns, furniture fittings, bathroom fittings, etc, These supplies, although they seem to have nothing to do with, all need to use wear-resistant, corrosion-resistant, high-strength zinc alloy parts to ensure their service life.
Aluminum castings
- Automobile Industry
The use of aluminum alloy castings in modern automotive manufacturing has increased dramatically. Engines, engines, transmissions, support frames, body parts including wheels, and even light-emitting diode (LED) radiators are all made of aluminum alloy castings. This is mainly because aluminum alloy casting density, high strength, thermal conductivity, wear resistance, corrosion resistance, and other characteristics can effectively reduce the weight of the car so that the car’s performance is superior.
- Electronic industry
Aluminum alloy castings in the electronics industry are also more and more widely used. Such as organic chemicals separation column, computer central processing unit (CPU), graphics cards, communications equipment, and other high-quality small parts made of aluminum alloy castings. Aluminum alloy castings not only have good thermal conductivity but also ensure good heat dissipation of electronic components, and improve the efficiency and life of electronic equipment.
- Aviation industry
Aluminum alloy castings are widely used in the construction of aircraft, rockets, satellites, and other aircraft. The proper functioning of aluminum alloy castings ensures the durability, strength, and lightweight of the aircraft, making this material well-suited for the aerospace sector. In addition, with the emergence of a new generation of aircraft, aluminum alloy castings are lighter and thinner, with higher strength, rigidity, and corrosion resistance, making them more suitable for the aerospace industry of the future.
- Medical equipment
In the field of medical equipment, aluminum alloy castings also play an important role. Aluminum castings can be made into medical instruments and surgical instruments. For example, after special passivation treatment aluminum alloy can be made into internal components of pacemakers, artificial joints, knee surgery repair with bone nails, etc., while aluminum alloy castings have anti-magnetic and good oxidation performance, suitable for MRI and other medical equipment.
- Construction
Aluminum alloy castings are also widely used in the construction field. Large bridges, high-rise buildings, interior decoration, etc. can use aluminum alloy castings, because aluminum alloy castings are of low density, high strength, and lightweight to help the overall structure of the building be more stable, and can greatly reduce labor intensity, reduce labor costs.
How to choose zinc die casting or aluminum die casting for your project?
Zinc Die Casting
- Production of complex-shaped parts.
- Smaller and more complex shapes.
- Fast cycle times and large batch sizes.
- Parts are used in harsh environments.
- Lower cost.
Aluminum castings
- Lightweight design parts with a high strength-to-weight ratio.
- Parts with high strength and rigidity.
- Larger and simpler parts.
Summary
Zinc castings and aluminum castings each offer advantages in different ways. Choosing the right material depends on specific project needs, including design requirements, performance needs, cost budgets, as well as environmental and sustainability considerations, etc. Easiahome has experienced engineers with over 16 years of die casting expertise to evaluate your needs and help you decide which alloy is right for your application.
