It is a well-known die casting method used to produce complicated zinc parts. Die casting of zinc gives extraordinary strength, corrosion resistance and light weight parts. Therefore in this post we will cover what Zinc Die Casting is as well as its process, benefits and uses in different sectors.
What is Zinc Die Casting?
In simple words it’s a highly precise manufacturing process in which molten zinc alloy under high pressure is forced into steel molds. Since the melting point of zinc is so low, this hot chamber process is usually done at lower temperatures. This in turn makes it possible to produce complicated parts with walls as narrow as 0.008 inches.
Process of Zinc Die Casting
Preparation of Mold
The first step in this casting is preparation of mold. Mold is normally made of steel or some other long lasting material (e.g. aluminium). This mold is then customized to the specifications of the part to be cast.
Melting & Injecting the Alloy
In second step the zinc alloy is melted at temperatures between 370 and 430 °C in a furnace chamber. After that the molten metal flows into shot chamber by gooseneck mechanism. The liquefied zinc is then forced by hydraulic plunger into the die cavity under great pressure with the help of logic valves to assure accurate flow control.
Cooling and Solidification
Once injection is done the next stage is to quickly cool and solidify molten zinc within die. Cooling time is carefully controlled so that part preserves its dimensional accuracy and shape. It depends on the part complexity but usually it takes a few seconds to a couple of minutes to cool.
Ejection
After zinc solidifies, die halves open and casting is pushed out of mold cavity by ejector pins. Proper ejection force is needed because of shrinkage in cooling step which can cause sticking or deformation. After that the mold is ready for next cycle.
Trimming & Finishing
Once mold is ejected, saws, vibratory degating machines or trim dies are used to trim extra material like runners or flash. But it may need extra finishing operations like buffing or polishing to fulfill necessary dimensional and surface quality specifications.
Quality Checkup
Finally the finished part is inspected for quality to confirm that it complies with aesthetic, dimensional and mechanical standards. It includes coordinate measuring machines (CMMs), non destructive testing (leak detection) as well as visual checks. If there are any problems, then part must be rejected or reworked.
Most Used Alloys of Zinc
1- ZAMAK Alloy
ZAMAK is a family of zinc based alloys which contains magnesium, copper and aluminum. Because of their durable nature, they are usually employed in large volume production of parts.
ZAMAK 2
A zinc alloy with high copper content (2.5-3%). And it gives outstanding casting fluidity, resistance to corrosion and vibration damping. This alloy can also be post processed, and used to make complicated parts.
ZAMAK 3
ZAMAK 3 is a well-known zinc alloy and consists of 96% zinc and 4% aluminum. Its smooth finish and ease of processing make the alloy an often used material in applications such as decorative items and consumer electronics.
ZAMAK 5
ZAMAK 5 has 96% zinc, 3.8% aluminum and 1% copper. And compared to ZAMAK 3, it gives better corrosion resistance, hardness and strength. Moreover it has outstanding dimensional stability and creep resistance at elevated temperatures.
ZAMAK 7
Zamak 7 is a pure zinc alloy and has better ductility and fluidity because of low magnesium content. It has tensile strength of 170 MPa (approx.) and Brinell hardness of 70.
2- ZA Alloys
Zinc aluminum alloys or also known as ZA alloys are alloys that have greater heat resistance and strength than conventional ZAMAK alloys. Such alloys are perfect for applications which demand thermal stability and strength simultaneously.
ZA-8
The zinc–aluminium alloy ZA–8 contains 8% aluminium and has outstanding creep resistance, strength as well as hardness. Besides that it is the only ZA alloy appropriate for hot chamber die casting because it provides good castability for thin walled parts and complex designs.
ZA-12
ZA 12 is cold chamber zinc alloy which contains 12% aluminum. And it provides outstanding hardness (107 Brinell), wear resistance and strength (46 ksi yield). ZA-12 is good for applications where non sparking characteristics and dimensional stability are required.
ZA-27
Among ZA alloys ZA 27 is the lightest and strongest alloy with 27 % aluminum. Apart from that, it has impressive tensile strength of 426 MPa along with wear and bearing properties.
Advantages
- Zinc alloys give extraordinary toughness, rigidity and strength for high performance applications. Due to their impressive impact resistance and tensile strength, they increase lifespan of components even in most aggressive conditions.
- Zinc die casting provides minimum material waste, energy proficient procedures and rapid cycle times which decrease production costs. Besides that it eliminates the need for secondary machining.
- Zinc casted molds last much longer as zinc is less abrasive and has low melting temperature. The tools can produce more than thousand parts which reduces replacement costs and improves production proficiency.
- Parts made by this zinc casting does not corrode naturally. They create protective layer of zinc oxide when exposed to air. In harsh environments such as marine and outdoor applications, this durable barrier protects against rust.
- Zinc is capable of reaching tight tolerances up to ±0.001 inches and capturing fine details because of high fluidity. This precision as a result permits production of complicated, net shaped parts with smooth surface finishes.
Applications of Zinc Alloy Die Casting
Automotive Industry
In vehicles this process is greatly used for components such as door handles, engine brackets, brake systems, fuel system parts and seat belt mechanisms. For both exterior and interior use cases, its repeatability and precision assure lightweight and durable design.
Medical Field
Diagnostic equipment components, dental tools, prosthetic devices and surgical instrument parts are all made using zinc casting.
Electronics
Zinc casting is used to make connectors, heat sinks, switchgear components, battery casings, electronics housings etc. It dissipates heat away from delicate electronic components because of its good thermal conductivity.
Telecommunications
In telecom zinc die casting is important for producing RF shielding enclosures, antenna components, fiber optic connectors and satellite communication parts. The process produces parts that are strong, lightweight and suitable for daily use
Consumer Goods
Zinc die casting is broadly used to make consumer goods. This process makes door handles, decorative hardware as well as kitchen appliances. For high demand products, its ability to produce complex designs with good surface finishes guarantees aesthetic appeal, cost effective production and durability.
Heavy Machinery
Complex parts for industrial machinery are often produced using zinc die casting. These include gear components, mechanical linkages and transmission housings. Apart from that, this process provides better strength to weight ratio for heavy duty equipment.
Comparison With Other Materials
Zinc vs Aluminum
Aluminum die casting demands more complicated processing owing to its lower fluidity. As a result, complex mold can be difficult to fill. In addition, aluminum has greater tendency for shrinkage during cooling.
Zinc die casting on the other hand has higher fluidity which makes zinc easy to process. Therefore it is comparatively easier to fill molds and keep better dimensional accuracy in zinc die casting.
Zinc vs Magnesium
Magnesium die casting requires highly careful processing as magnesium is highly reactive. And it requires special environment and high temperature in range of 650–700 °C. However zinc is less reactive and its casting temperature is usually below 385 °C. It provides better surface finishes as well as corrosion resistance.
To Sum Up
In short zinc die casting provides very precise, strong and economical production of complex parts. And it is suitable for different industries because of its fluidity, corrosion resistance and longer tool life.
If you require any kind of custom mold for zinc casting or any casting, then RICHCONN is best option. You can contact us at any time.
Common Questions
How does die casted zinc compare to solid brass?
Brass cannot match zinc in cost effectiveness and flexibility of design. Moreover brass has better thermal properties while zinc gives more dimensional precision & economical bulk production.
Do die-casted zinc parts rust?
No these parts do not rust. When exposed to air they form a zinc-oxide layer which gives them extraordinary corrosion resistance.
How to clean die-casted zinc?
Zinc die-cast parts should be cleaned by lukewarm water & mild soap. Do not use abrasive tools or harsh chemicals because they might scratch the protective oxide layer. And use special metal cleaners to clean stuck dirt on zinc-alloys.
In pressure die-casting why should you use alloys over pure zinc?
Compared to pure-zinc zinc-alloys give better mechanical properties like durability, dimensional stability and toughness.
Aside from that ⸴ addition of other elements in zinc such as copper and aluminium increases fluidity ⸴ decreases shrinkage as well as raises wear resistance of zinc.
Is die casted zinc magnetic?
No zinc die cast parts are non-magnetic because of their composition. Therefore they are suitable for electronic parts which need EMI shielding with no magnetic interference.