Zinc is a multipurpose and important metal with important roles in a wide industrial, commercial, and biological applications. Zinc is used industrially, in construction, and for protective coatings because of its high corrosion resistance and bluish-silver appearance. One of its most valuable properties is its ability to form very strong alloys, especially with aluminum, copper, and magnesium, and it greatly improves the strength and durability. Concerning manufacturing processes like die casting, these characteristics make zinc extremely suitable. Zinc is also known as a special material in the context of the automotive industry because there is no other material with such mechanical properties and at the same time with so many manufacturing advantages. It can be used in creating highly complex and detailed shapes with little machine work, which makes them perfect for both decorative and functional vehicle components. In addition to its low melting point, which makes for lower energy use during production, as per global sustainability objectives. Zinc’s importance is increasing as automotive technology evolves. Most airplane system parts can now be made from it because it supports high volume production with excellent part consistency, which makes it a critical material, not just for the current system designs, but also for their new designs for the future.

¿Qué es la fundición inyectada de zinc?

La fundición a presión de zinc es un proceso de fabricación de precisión que consiste en inyectar aleación de zinc fundida en una matriz a medida (también conocida como molde) a alta presión y presión para formar piezas metálicas. Normalmente se utiliza para la producción de componentes complejos y detallados con tolerancias estrechas, acabados superficiales finos y propiedades mecánicas elevadas.

La fundición a presión de zinc tiene excelentes propiedades mecánicas y combina al mismo tiempo una gran precisión. Permite fabricar piezas intrincadas, de tolerancias estrechas y acabados superficiales lisos, y es útil para los requisitos del diseño actual de vehículos.

¿Por qué el zinc? Propiedades clave del material

Por varias propiedades únicas, se prefiere el zinc en el proceso de fundición a presión.

High Strength and Ductility

Como es más resistente que muchos otros metales que se funden a presión, en aplicaciones de paredes finas se utilizan aleaciones de zinc.

Excellent Dimensional Accuracy

La fundición a presión de zinc es una pieza que mantiene sus formas y tamaños con gran consistencia, lo que ayuda a prescindir del postprocesado.

Resistencia superior a la corrosión

El zinc es naturalmente resistente a la corrosión particular a los revestimientos adicionales. Es crucial para las piezas utilizadas en vehículos en presencia desafortunada de las condiciones de la carretera y el clima.

High Fluidity

El zinc fundido fluye con mucha facilidad, y estas piezas con características pequeñas y paredes finas se fundieron con éxito.

Cost-Effective Tooling

La fundición de zinc se beneficia de matrices de larga duración en comparación con el aluminio o el magnesio; por lo tanto, hay más ventajas económicas en el zinc si se desea una gran tirada de producción.

Reciclabilidad

La transición de la industria automovilística hacia una mayor sostenibilidad también significa que el zinc es un material 100% responsable con el medio ambiente y reciclable sin pérdida de propiedades.

Manufacturing Process: Step-by-Step Overview

1. Design and Tooling:

Los ingenieros utilizan programas informáticos CAD para diseñar los componentes. A continuación, se fabrica una matriz de acero de alta precisión con un elevado número de cavidades para construir varias piezas en un solo ciclo.

2.  Melting the Zinc Alloy:

A unos 420 °C (788 °F) se funde el zinc, a una temperatura inferior a la del aluminio y con un coste energético considerablemente menor.

3. Injection:

Normalmente, el zinc fundido se inyecta en la matriz a una presión de entre 1.500 y 25.000 psi, lo suficientemente alta como para garantizar que el molde se llene rápida y uniformemente.

4. Cooling and Solidification:

Cuando la aleación de zinc entra en la matriz, se enfría rápidamente y se solidifica (cuestión de segundos).

5. Ejection:

A continuación, los pasadores eyectores expulsan la pieza recién formada de la matriz.

6. Trimming and Finishing:

La pieza puede someterse a un acabado adicional, como desbarbado, pulido, pintura o revestimiento, y se elimina el material sobrante (rebaba).

7. Quality Control:

Algunos componentes se inspeccionan para comprobar su precisión dimensional, defectos superficiales e integridad mecánica, como suele hacerse con sistemas automatizados o escáneres 3D.

Common Zinc Alloys Used in the Automotive Industry

En la industria del automóvil, la selección de la aleación de zinc adecuada es importante porque las propiedades de la aleación desempeñan un papel importante para el rendimiento y la fiabilidad adecuados, así como para la rentabilidad adecuada. Los fabricantes pueden adaptar los materiales a aplicaciones específicas en función del equilibrio entre resistencia, ductilidad, fluidez y resistencia a la corrosión que ofrecen las distintas aleaciones en distintas medidas. A continuación se indican las aleaciones de zinc más utilizadas en la fundición a presión de automóviles.

1. Zamak Alloys (Zinc-Aluminum Alloys)

El principal elemento de aleación en una familia de aleaciones de zinc conocidas como zamak es el aluminio a unos 4%. El nombre procede de los nombres alemanes de los metales utilizados: Zink, Aluminio, Magnesio y Kopper (cobre).

Zamak 3:

• Es la aleación de zinc más utilizada para la fundición a presión.
• Ofrece una excelente estabilidad dimensional, buen acabado superficial y capacidad de fundición.
• Estas superficies son habituales en componentes interiores como tiradores de puertas, pomos y piezas embellecedoras.

Zamak 5:

• Es ligeramente más cobrizo que el Zamak 3 y ofrece mayor resistencia y dureza.
• Apropiado para aplicaciones de tensión mecánica como soportes estructurales.

Zamak 2:

• La más fuerte y dura de las aleaciones de Zamak.
• Se utiliza en sistemas de cierre o carcasas de engranajes donde la resistencia al desgaste es crítica.

2. ZA Alloys (Zinc-Aluminum)

Las aleaciones ZA (ZA-8, ZA-12, ZA-27) tienen mayor contenido de Al que el Zamak, por lo que presentan mayor resistencia y resistencia al desgaste. Suelen utilizarse en fundición por gravedad, aunque en algunos casos también en fundición a presión.

ZA-8:

• Contiene aluminio 8%.
• Ofrece una buena resistencia y propiedades de colada moderadas.
• Adecuado para componentes estructurales de vehículos ligeros.

ZA-12 and ZA-27:

• Difícil de fundir, pero de mayor resistencia.
• Se utiliza en aplicaciones o piezas semiestructurales, donde está sometido a fricción.

3. ACuZinc5

Se trata de una aleación especial de zinc, cobre y aluminio destinada a obtener las características de capacidad de fundición del Zamak y la resistencia de las aleaciones ZA.

• Resistencia extremadamente alta y resistencia superior al desgaste.
• Applied in gear housings, actuators, and mechanical linkages in automotive systems.
• The change material is ideal for replacing machined bronze and steel in applications where durability is necessary.

4. EZAC (Enhanced Zinc-Aluminum-Copper)

A relatively new alloy, very high in strength and creep resistance up to elevated temperatures, EZAC is.

• Good for parts that have to hold shape and strength even under the load, for example mounting components or engines.
• It offers twice the strength of Zamak 3, but requires more advanced tooling.

5. Zinc-Nickel Alloys

Zinc-nickel plate is less common than zinc die casting for these areas, but it is frequently used to improve corrosion resistance (especially salt and moisture) for under the hood or undercarriage parts.

• Elegir la aleación adecuada
• The selection of zinc alloy depends on several factors
• Mechanical requirements (tensile strength, impact resistance)
• Surface finish needs
• Cost and production volume
• Exposure to environmental stress (heat, corrosion)

For that reason, engineers frequently work with material scientists and suppliers to choose an alloy that is as well suited to the task as cost may permit, meeting both performance and cost constraints.

Role of Zinc Die Casting in the Automotive Industry

Zinc die casting has great importance in automotive manufacture due to high precision, high strength and economical make of small-to medium sized components. This process offers the means to produce complex parts of high precision in a very short time period and is excellent for high volume automotive applications.

Excellent mechanical properties of zinc alloys, such as durability, corrosion resistance, and dimensional stability, are obtained. These are the things that make zinc the best choice for door handles, brackets, locks, emblems, etc., as an auto part. This also provides easy plating or painting since it has a smooth surface finish.

Although zinc is heavier than aluminum or magnesium, it can be competitive for applications where weight is not the highest priority in terms of strength and detail. Due to its low melting point it requires less energy usage and has a long tool life. Zinc also is 100% recyclable, which supports accelerating the automotive industry’s promotion of sustainability.

Zinc die casting is still providing reliable and high-quality solutions for automotive demanding applications as vehicle designs evolve.

Physical and Chemical Properties of Zinc 

Propiedades físicas del zinc

1. Appearance:

The thermoelectric bluish silver or grayish metal has a shiny metallic luster when freshly polished.

2.  Density:

Since at room temperature Zinc has a density of about 7.14 g/cm³, it is moderately heavy in comparison with other metals.

3. Melting Point:

However, at a relatively low temperature of 419.5°C (787°F), zinc is suitable for thermal processes, such as die casting, where low energy consumption is desired.

4. Boiling Point:

Zinc boils at 907°C (1665°F).

5. Hardness:

Zinc is about 2.5 on the Mohs scale of hardness, which makes it not too hard compared to steel, but not too soft as pure tin or lead are.

7. Electrical Conductivity:

However, while copper and silver are very good conductors of electricity, zinc is not quite as conductive. Because of this property, it is often used in batteries and electroplating.

8. Thermal Conductivity:

The moderate thermal conductivity of zinc makes it useful in managing heat, but it is less efficient than aluminum.

9. Malleability and Ductility:

Zinc is brittle, and thus can easily break at room temperature. It is however malleable when heated to around 100–150°C (212–302°F), one can easily shape them.

10. Crystal Structure:

In addition binary compounds of zinc are zinc crystallizing in a hexagonal close packed (hcp) structure which affects the mechanical properties especially the brittleness at lower temperatures.

Chemical Properties of Zinc

1. Reactivity with Air:

After coming in contact with air, zinc forms a thin layer of zinc oxide (ZnO) on the surface. Zinc on the top side prevents deeper corrosion and is therefore very resistant to atmospheric oxidation rusting.

2. Reactivity with Acids:

Dilute acids like the dilute acid hydrochloric acid (HCl) can react easily with zinc to give up hydrogen gas (H₂). Therefore, this property makes zinc useful in galvanization and sacrificial anodes for corrosion protection.

3. Amphoteric Nature:

Zinc is amphoteric, and can be acted upon by both acids and powerful bases. For example it reacts with sodium hydroxide (NaOH) to give sodium zincate.

4. Alloy Formation:

Zinc readily alloys with several metals, including copper, to produce brass, aluminum, magnesium, and many other metals.

5. Oxidation States:

The +2 (Zn²⁺) oxidation state of zinc is the most common. This oxidation state is combined with zinc compounds such as zinc oxide (ZnO) and zinc sulphate (ZnSO₄).

6. Resistance to Water:

Pure water does not react with zinc at room temperature, but at higher temperatures, zinc can react with it, slowly forming hydrogen gas and zinc oxide.

7. Galvanic Activity:

The anode material, zinc, is very effective because it readily loses electrons in galvanic cells (batteries).

Zinc vs Other Materials in Automotive Applications

Unlike aluminum, magnesium, plastic or steel, zinc die casting has several advantages. Zinc shines for its key performance and cost in automotive design, and while each material may have its place in automotive design, zinc is particularly effective in those parameters.

Zinc vs Aluminum:

In a form that is often selected for its light weight, aluminum is too weak and too soft at low thicknesses compared with zinc. Additionally, zinc provides better dimensional stability and additional complex geometries don’t require extensive machining. Tooling for this kind of casting also tends to last for longer periods, so it means that long term production costs are lower.

Zinc vs Magnesium:

Zinc is lighter than magnesium but is more expensive when bought without special coating. However, zinc alloys offer excellent corrosion resistance and do not require any additional surface treatments to make them resistant in most environments. Also, casting zinc provides better casting precision and finish.

Zinc vs Plastic:

However, plastic is lightweight, inexpensive, but comparatively weaker, does not withstand temperatures very well and is less durable than metal. Zinc components withstanding wear, impact or load bear are a solid alternative when structural integrity, lifespan and resistance to damage from impact or wear are important, in particular where movement or load carrying is involved.

Zinc vs Steel:

Steel is a good material that is strong and is quite commonly used in structural applications, but it is much heavier, and in many cases, more costly to form into ornery shapes. Zinc die casting, because it produces near net shape parts with minimal post processing, is well suited in cases where small and medium sized components are to be produced.

In general, zinc provides a good balance between mechanical strength, cost, formability, and surface finish and is therefore an excellent material for automotive parts regardless of their function.

Summary Table of Zinc’s Key Properties

Applications of Zinc Die Casting in Automotive Manufacturing

A wide range of components for vehicles can be processed via zinc die casting. Some of which are most common, such as:-

1. Componentes interiores:

• Tiradores de puerta
• Seat belt hardware
• Dashboard control levers
• HVAC knobs and switches

The components in these are high precision, tactile feel needs to be good, and the fit has to be a great finish. The ability of zinc to provide fine surface detail and dimensional accuracy is suited for these parts that are visible and used frequently.

2. Componentes exteriores:

• Emblems and logos
• Door and trunk locks
• Mirror brackets
• Wiper system components

Since noise, however, often indicates the cause of noise and the location of its cause is not as important as the noise itself, corrosion resistance and strength are used for use after environmental exposure and give appearance and function.

3. Componentes bajo el capó:

• Carburetor parts
• Fuel system parts
• Valve bodies
• Timing belt covers

Both thermal stability, strength and wear resistance are essential for these parts. Complex geometries, high precision tolerances and fluid engine system applications are achieved through zinc die casting.

4. Piezas estructurales:

• Soportes
• Mounting plates
• Chassis supports (in smaller vehicles)

Although not used for primary load bearing structures, zinc components have stiffness and reliable mechanical properties that make them useful in supporting frames and assemblies.

Zinc’s flexibility meets decoratively and functionally said requirements in all classes of vehicles. Because of its capacity to cut post-processing, EMI shielding, and component consolidation, zinc die casting extends to more and more electric and conventional platforms.

Ventajas de la fundición a presión sobre otros materiales de fundición a presión

Although aluminum and magnesium have also been used in the automotive sector, zinc has an advantage:

It is easy to see that for small to medium sized components in which precision and strength are of great importance, zinc die casting is a very good option.

Retos de la fundición inyectada de zinc

Zinc die casting has some disadvantages:

Peso:

Zinc is too heavy to use in electric vehicle chassis and other applications where weight reduction is critical because it’s heavier than aluminum or magnesium.

Propiedades térmicas: 

Thermal conductivity of zinc is lower than that of aluminum, so it is not suitable for heat dissipation parts like engine radiators.

Limitaciones de tamaño:

For example, the tools cannot be used to cast very large components, and solidification defects can occur.

Yes, given intelligent engineering and hybrid material design, most of these challenges can be addressed.

Factores medioambientales y de sostenibilidad

Zinc die casting stands out because the global automotive industry leans towards greener practices.

100% Reciclabilidad:

Zinc casting scraps are collected and reworked without any degradation.

Eficiencia energética:

Since aluminium has a much higher melting temperature, the energy consumption is significantly lower than with aluminium.

Larga vida útil de las herramientas: 

It lengthens the die life, lessening the frequency of tool replacement, which means less waste and time without production.

As a result, companies working towards meeting more rigorous environmental regulations are drawn to zinc as it is an excellent option that won’t compromise quality or performance.

Innovaciones y tendencias futuras

Tecnología de pared delgada:

Dies that have been advanced, and more fluid zinc alloys, have now enabled parts with extremely thin walls, reducing weight without losing strength.

Montajes híbridos: 

Also, zinc parts are being used more and more in combination with plastics or other metals for multifunctional parts.

Vehículos eléctricos (VE): 

EVs need compact and robust components for battery housings, control systems, and connectors, and zinc is showing promise because of its precision and as an EMI (electromagnetic interference) shielding metal.

Herramientas inteligentes: 

In mass production, the use of AI and machine learning for die maintenance also helps to reduce the die life and defects.

Conclusión

Fundición a presión de cinc is more than a manufacturing method; it’s a winning strategy to achieve the competitive automotive edge. It presents a combination that is optimal regarding mechanical strength, design flexibility, cost efficiency, and sustainability. Since vehicles are moving towards becoming lighter, more environmentally friendly, and more sophisticated, zinc die casting has an important role to carry it forward as the next generation of automotive components. Zinc has huge use from small interior knobs to powerful under hood structures in automotive manufacturing. Once innovations continue to refine their application, the years ahead will deliver even wider adoption on conventional, hybrid, and electric vehicle platforms.