Zinc Die Casting Products: The Ultimate FAQ Guide

This guide answers all questions you have been asking about zinc die casting products.

Whether you want to learn about the benefits, choosing alloy, zinc die casting process, quality inspection or any other information – this guide has all you need.

So, keep reading to learn more.

Why Is Zinc Die Casting Products Better Than Die Casting Aluminium Or Magnesium Parts?

• Zinc die casting has a low melting temperature hence quicker to manufacture compared to aluminium which has a high melting temperature.
• Aluminium alloy is a lightweight while zinc alloy is heavier thus energy efficient and has lower production cost hence is good where weight is less important.

Zinc die casting

• In casting zinc strength is higher than aluminium alloy hence the precision is significantly good and the wall thickness can be reduced.

die casting aluminum

• Zinc alloy lifetime is more durable compared to aluminium alloy which have a maximum life time of 100000 shots.

magnesium parts

Which Zinc Alloys Are Suitable For Die Casting Products?

Here are most common zinc alloys;

Zamak 2

It has a great strength compared to other alloys due to 3% copper increase in it hence making it expensive than others.

Has the same composition as zamak 3 hence composed of magnesium, copper, zinc and aluminium.

Zamak 2

It is used for die casting hence it is also known as Kirk site.

Also used for mandrels for metal spinning.

Zamak 3

It is the most used zamak alloy compared to other alloys.

Composed of 90% zinc ,10% aluminium.

Mostly preferred for die casting.

Zamak 3

Zamak 4

It helps in ductility of zamak 3 hence it reduces the effects of die soldering.

Zamak 4

Zamak 5

It also has same composition as zamak 3 but has addition of 2% copper hence to increase its strength corrosive resistance and hardness.

Zamak 5

Zamak 7

It is used in casting thin wall hence has less magnesium to increase ductility and fluidity.

Nickle is added to it to reduce inter-granular corrosion and more impurities are also controlled.

Zamak 7

What Are The Benefits Of Zinc Die Casting Products?

Here are some of the benefits of zinc alloys;

• Zinc alloys produces a precise and resilient casting with high fluidity when it is molten.
• They are tough and have great rigidity than aluminium counterparts.
• Die casting zinc alloys are stronger hence they can be produced with thinner walls and less material to optimize strength compared to other materials like plastics and aluminium.
• Another advantage is that zinc alloys have a lower melting temperature hence it can last 20 times longer than aluminium alloy.
• When using zinc alloys, they provide a decorative and a great adhesion of any finish to its substrate thus these finishes are corrosion resistance.
• Zinc alloys also allows surfaces to act as brushings for structures in motion since they have good waring and bearing properties.
• They are also 100% recyclable hence all the by-products of the casting process can be remelted and cast again without degradation.
• Its fluidity provides increased precision hence allowing designs that do not require additional expensive machining.
• They are cost effective since they solidify rapidly in lower melting temperature thus producing more parts in the same amount of time.

Why Is Hot Chamber Die Casting Suitable For Zinc Die Casting Products?

Hot chamber die casting is suitable because it uses alloys with low melting temperatures like zinc alloys hence to avoid damage to gooseneck and other components.

hot chamber die casting

What Are The Benefits Of Hot Chamber Zinc Die Casting Products?

• The casting cycles are shorter hence has a higher production capacity.
• It offers longer tool life since it utilizes low melting point alloys which has less impact on the die.
• Hot chamber is more efficiency due to the machine containing an internal melting pot.
• It has less wasted metal hence it is more environmentally friendly.
• Reduced porosity.

Are There Limitations Of Hot Chamber Zinc Die Casting Products?

• In hot chamber die casting cannot fully heat since there are pores on the surface hence it will lead to formation of blisters on the surface of the metal.
• It offers limited metal fluidity due to variance in alloy malleability hence limiting the final products shape.
• Hot chamber is only cost effective if you have a high volume of products that need to be produced.

What Are The Components Of Hot Chamber Die Casting Machine For Zinc Products?

The following are parts of hot chamber;

• The injection
• The furnace.
• The plunger.
• Ejector pins.
• Ejector dies.
• gooseneck

How Does Hot Chamber Zinc Die Casting Products Work?

The hot chamber system is used with metals such as; magnesium, lead and zinc.

The furnace on the machine is attached by a metal feed system called gooseneck where the injection process of a hot chamber is thrust in the molten metal.

Then molten metal is then allowed to fill the cylinder by closing the die and piston rising to open the port.

The molten metal is then pushed through the gooseneck and nozzle into the die cavity when the plunger seals the port hence it is held under pressure until it solidifies.

When the die open, the molten metal flows back through the nozzle and the gooseneck hence the casting remains in the ejector side.

Then ejector pin pushes the casting out of the ejector die thus the molten metal flows through the inlet to refill the gooseneck.

Which Temperature Is Best For Zinc Die Casting Products?

The parts are melted at the temperature of about 380-420c adjacent to the die casting machine hence the alloy is injected into a mould.

When the melting temperature is too low, the flow property will be poor hence it will affect the surface quality of the zinc die casting.

When the temperature is high, the casting crystallization is good and mechanical performance is reduced.

Is High Pressure Necessary For Zinc Die Casting Products?

Absolutely yes.

High pressure die casting involves;

Preparing The Mould.

At this stage the lubricant is applied to the interior walls of the mould hence to regulate the moulds temperature and for easier removal of casting.

Injection.

After preparing the mould, the molten metal is then injected in it when the mould is tightly sealed and closed.

The mould has to maintain the pressure until molten metal has cooled and solidified.

Cavity Injection.

The new cavity from the mould is then ejected by the manufacturing company using automatic ejector pin.

This process cannot be accomplished if the cavity is still liquid hence it has to be solid for it to eject.

Shakeout.

At this final stage, any excess scrap metal is separated from the new cavity before the mould can be reused.

The moulds are durable hence more parts can’t be manufactured to decrease the number of components requested.

The fusion has a good surface finish thus reducing the thickness of the plate walls hence reducing the overall weight of the fusion.

It has a higher production speed when compared to the flow pouring under the effect of gravity.

High pressure has the ability to produce flows of specific dimensions hence to re3duce processing operations.

Which Defects Are Common During Zinc Die Casting Products Process?

Zinc die casting alloy has many sources to cast defects hence here are some of the common defects, causes and their remedies;

Cracks.

Cracks appears when a metal does not have sufficient strength to resist tensile force during solidification.

To avoid cracks, set die coat spray properly in proper mixture hence maintain die temperature within limit by setting die open time.

Blisters.

With high die temperature, a thin film of small surface blows up on the surface of the component.

Proper flow of die coat spray is usually maintained to prevent blisters hence proper mixture of die coat chemical is done.

Blow Holes.

This occurs when there is no proper venting hence the metal can’t hold as much gas as the fluid form.

It is prevented by proper venting thus set spray for adequate amount of die coat.

Pin Holes.

It is also known as porosities.

They are usually found on the upper part of the mould in poorly vented pockets hence they appear in large numbers at the surface of the casting.

Fusion.

It adheres to the casting thus it is thin with brittle and glassy appearance hence occurs when sand grains fuse with molten metal.

Swells.

This are enlargement of the casting hence they are smooth bulge on the vertical face of the casting.

Drops.

This occurs when the metal is still in liquid hence when the pieces of sand fall into the metal casting.

Metal Penetration.

During the moulding sand the liquid metal penetrates in the gaps hence they are rough and uneven surface finish of the casting.

Warping.

This can happen during or after solidification hence they change in the dimensions of the final product.

Mismatch/Shift.

It is a horizontal displacement of a metal hence it is due to misalignment of upper and lower part of the mould.

How Can You Eliminate Defects Of Zinc Die Casting Products?

• Maintain die temperature within limit by setting die open time, die open and close speed properly.
• Check and maintain injection pressure and maintain oil pressure.
• Provide proper venting.
• Check and maintain continuous cycle time and die opening time.
• Check and open choked die cooling.
• Insert internal chills, cooling ribs to increase local heat dissipation.
• Limit the total volume deficit by reducing casting temperature.
• Inspect and replace any defective moulds before casting.

How Do You Check Quality Of Zinc Die Cast Products?

Destructive Test.

This test is used to detect the porosity during the casting period hence the porosity can weaken the integrity of the final part.

Visual Test.

This is established by the customer by looking hence a piece of zinc may not look right visually thus it may require retooling.

Leak Test.

This is done using an air decay leak tester hence to detect if the casting is leaking due to porosity and worn-out dies.

Poke Yoke Method.

The method is used to detect poor trimming process by leaving excess material on your part. The procedure helps you prevent poor die cast maintenance and poor design

Are Zinc Die Cast Products Strong?

Absolutely yes.

The parts provide a greater impact of resistance to shocks, wear and corrosion compared to other alloys hence they are versatile in finishing the articles.

Its ductility and good strength allow to have flexibility in the design of small parts and details.

They are tough and have great rigidity than aluminium counterparts.

zinc die cast

Die casting zinc alloys are stronger hence they can be produced with thinner walls and less material to optimize strength compared to other materials like plastics and aluminium.

They are also 100% recyclable hence all the by-products of the casting process can be remelted and cast again without degradation.

Its fluidity provides increased precision hence allowing designs that do not require additional expensive machining.

Where Can You Use Zinc Die Cast Products?

Zinc die cast products can be used in;

• Power steering system.
• Electronic devices.
• Brake parts and systems.
• Fuel system.
• Interior automotive aesthetic parts.
• Air-conditioning systems and components.

Will Zinc Die Cast Products Rust?

Yes, zinc rust when exposed to air and moisture.

They offer corrosion resistance hence when they react with oxygen to form a thin oxide layer which reacts with moisture to produce zinc hydroxide.

It works best for the application that are not based to high temperatures due to its smooth surface finish.

Zinc rate of corrosion is 1/30 that of steel hence metals coated with zinc-based products have a longer life time when exposed to atmosphere.

When the zinc surface has not fully developed the protective carbonate layer, it exhibits a corrosion known as white rust.

It occurs when there is lack of free air over the zinc surface hence the white rust is powdery in appearance.

How Does High Pressure Zinc Die Casting Products Work?

High pressure die casting involves;

Preparing The Mould.

At this stage the lubricant is applied to the interior walls of the mould hence to regulate the moulds temperature and for easier removal of casting.

Injection.

After preparing the mould, the molten metal is then injected in it when the mould is tightly sealed and closed.

The mould has to maintain the pressure until molten metal has cooled and solidified.

Cavity Injection.

The new cavity from the mould is then ejected by the manufacturing company using automatic ejector pin.

This process cannot be accomplished if the cavity is still liquid hence it has to be solid for it to eject.

Shakeout.

At this final stage, any excess scrap metal is separated from the new cavity before the mould can be reused.

high pressure zinc die cast

Why Choose High Pressure Zinc Die Casting?

The moulds are durable hence more parts can’t be manufactured to decrease the number of components requested.

The fusion has a good surface finish thus reducing the thickness of the plate walls hence reducing the overall weight of the fusion.

It has a higher production speed when compared to the flow pouring under the effect of gravity.

High pressure has the ability to produce flows of specific dimensions hence to reduce processing operations.

The process is cost effective since the casting cycles are short compared to other methods as the molten metal solidifies quickly.

It is good when creating lightweight casting since the casting can produce wall thicknesses as low as 1mm.

Are There Limitations Of High Pressure Zinc Die Casting?

It has casting porosity hence can be caused by selecting the wrong alloy for the cast but evacuated chamber may reduce this.

The components created through high pressure cannot be fully heat treated due to the presence of pores which will lead to formation of blisters.

When compared to gravity die casting, it is considered inflexible.

When using high pressure die casting  a large capacity investment is needed for the set up.

High pressure die casting uses complex and expensive equipment.

The dies are usually costly hence high pressure die casting costs are only considered with high-volume production runs.

Which Surface Finishes Do You Use After Zinc Die Casting Products?

• Polyester powder coatings.

Dry electrostatic process is used during this coating as powder hence solvents are not used to prevent the formation of solvent caused defects.

• Sprayed coatings

it involves different chemistries like polyester, phenolic and epoxies.

• Zinc black.

This process helps in corrosive environment hence a thick black phosphate is conferred to the casting.

• Copper-tin-zinc electroplate.

The coating turns the finish to black though it gives zinc a correct protection thus it is dull and silvery on the zinc surface.

• Galvanize coating.

This coating help to protect the metal from corrosion and improves the appearance of the surface.

The desired appearance is achieved only by selecting chromium [111] containing passivation such as black passivation, thin film passivation and thick film passivation.

• Black oxide.

It protects metal from corrosion hence it acts as an absorbent to hold oils.

It has a uniform black finish that is used to sport spark plugs, furniture brackets where a black surface is needed.

Black oxide provides a variety of valuable [properties hence improving the performance characteristics of a component.

• Black chromate with zinc.

This type of coating is applied over zinc plating during the surface coating process.

It corrodes before the base metal hence it is a corrosion resistant finish, ductile and soft.

• Electroless nickel.

Electroless nickel provides deposit properties within deep recesses and blind holes hence they give good corrosion, wear and abrasion resistance, electrical properties and hardness.

We have three types of electroless nickel which are;

• Low phos.
• Mid phos.
• High phos.

• Black E-coat.

It is an electrically applied paint coating thus it is used in decorative that enhances the appearance of parts hence also protecting the surface of parts.

• Black anodizes.

Black anodize particles are boiled in a solution of nickel acetate to produce non-conductive protective coating.

This helps to achieve adequate corrosion resistance thus sealing the component effectively.

Is Cold Chamber Zinc Die Casting Products A Perfect Die Casting Alternative?

This is used for metals that have high melting point such as; copper, zinc alloys, brass and aluminium alloys.

The molten metal is ladled into the cold chamber shot sleeve and the die closes.

The plunger then pushes the molten metal into the die cavity where it is held under pressure until it solidifies.

cold chamber zinc die casting

The casting remains in the ejector die while the die opens and plunger advances hence the ejector pin push the casting out of the ejector half of the die.

For all your zinc die casting products from China, contact us now.