Pressure Die Casting Parts: The Ultimate FAQ Guide

If you have any question about pressure die casting parts, you will find the answer right here.

So, keep reading to learn more

What Is Pressure Die Casting Parts?

With a high degree of precision and repeatability mass-producing means of low temperature metallic components is pressure die casting.

It is reliable, quick and cost-effective manufacturing process that are net-shaped, tight tolerances for production of high volume and metal components.

pressure die casting parts

Automated process, the liquid metal and alloy is injected unlike gravity die casting under high force into a hardened steel tool.

To form a net shaped component it gets solidified rapidly from milliseconds to a few seconds.

It is extracted automatically.

Why Choose Pressure Die Casting Parts?

• With high levels of accuracy it has ability to produce high volumes of identical metal components.
• For the mass production of castings it is cost-effective.
• For faster production in a matter of seconds or even milliseconds molten metal solidifies.
• Before need of replacement, it can produce thousands or even millions of components.
• For a wide range of applications it is ideal.
• For precise highly complex components it is great.
• Where large volumes are needed or long production runs it is suitable.
• Good surface finish close dimensional control.
• Castings with lighter weight thin walls.
• Without any further processing most pressure die casting’s can be discreetly electroplated.

What Are The Limitations Of Pressure Die Casting Parts?

• Expensive and complex equipment required.
• Require a large capital investment for the setup.
• When compared to gravity die casting relatively inflexible.
• Limited production runs or individual casting is less suitable due to how few they are thus become proportionately more expensive.

Which Machines Do You Need For Pressure Die Casting Parts?

Operating with Buhler Real Time Closed Loop Control Pressure die-casting machines quipped with specialist CNC foundries.

Industry-leading technology to produce high-quality castings their ability to replicate at huge levels is unmatched.

How Does Low Pressure Die Casting Parts Compare High Pressure Die Casting Parts?

Components produced in low pressure die-casting is relatively slower than those in high-pressure processes.

Size of castings is limited by size of machine thus high pressure die-casting, which is mostly carried out in zinc and aluminum soft alloys.

low pressure die casting parts

The different high-pressure and low-pressure die-casting capabilities and restrictions processes.

When choosing a method of production to meet your component requirements need to be taken into account.

Around 20% of light metal casting is Low-pressure die-casting.

High-pressure die-casting is the most commonly used which accounts for around 50% of light metal casting.

Alloys with low melting points low pressure die-casting are primarily used and allows for the production of up to around 150 kg components.

Very high strength and the ability to form complex geometries advantages, whilst maximising material usage.

high pressure die casting parts

For very thin-walled parts where the required thickness is less than 3mm the process is less suitable.

Smoother surfaces for finishing options will be provided by high-pressure casting depending on the quality of finish on the dies.

What Determines Cost Of Pressure Die Casting?

On the hourly rate and cycle time the production cost is mainly calculated. The size of the die casting machine is proportional the hourly rate.

To understand how the design of the part affects the machine selection is important, cost reduce by reducing time.

How Does Low Pressure Die Casting Parts Work?

Die is filled with metal from a pressurised furnace in low pressure die casting with typical pressure of around 0.7 bar.

In the lower part of the vertical die casting machine, the holding furnace is positioned.

To apply to various casting molds, casting various alloys, sizes the pressure and speed during pouring can be adjusted.

To avoid the involvement of gas and the erosion of the molding wall and core.

Adoption of bottom-injection filling, metal liquid filling stability and no splash phenomenon to improve casting qualification rate.

Under pressure the casting crystallizes its dense structure, clear outline, smooth surface and high mechanical properties.

For the casting of large thin-walled parts it is beneficial.

It increase the metal utilization rate to 90-98% and eliminates the need to fill up the riser.

Easy to realize mechanization and automation, Low labor intensity, good labor conditions, simple equipment.

How Does High Pressure Die Casting Parts Work?

Under pressure the process of forcing molten metal into a sealed mould cavity is called high-pressure die casting.

By a powerful compressive power it is held in place until the metal solidifies.

The die is released following solidification, opened and the metal released.

How Do You Choose Tooling For Pressure Die Casting?

• The part size to be casted
• Required volume of parts
• Family sets of parts required
• Core slides desirability
• Cast-in inserts required

How Does Vacuum Die Casting Parts Compare To Pressure Die Casting Parts?

The mechanical properties improved by an advanced die-casting process and surface quality of die-casting parts is vacuum die casting.

vaccum die casting parts

Significantly reduce pores, remove dissolved gases in the die-casting part by extracting gas during the die-casting process in die-casting mold cavity.

pressure die casting parts

While low temperature metallic components produced by means of mass with a high degree of precision and repeatability is Pressure die casting.

Which Parts Can You Make Through Pressure Die Casting?

• Casting Automobile Equipment.
• Casting Scientific Equipment.
• All Non-Ferrous and Aluminum Parts.
• Components of Pumps and Valves.
• Earthmoving Equipment.
• Equipment for Agriculture.
• Process Chemical Equipment.

Which Pressure Die Casting Defects Are Common?

Gas porosity

Turbulences are generated due to fluid high speed during filling phase including air or other gases.

If concentration of gas is not homogeneous inside casting during solidification phase,

air bubbles generate cavities thus weakening component resistant sections.

Depending on gas type entrapped during filling phase the rounded cavities e.g. air, water or lubricant can be shiny or opaque.

Shrinkage porosity

During solidification and cooling phase of casting shrinkage porosity defects are created due to material shrinking.

Material tend to move near colder zones during solidification phase.

Thus different temperature concentrated inside the part between casting surface, core and cavities.

These cavities morphology has an angular shape.

For hot spot setting up, part and runner geometry is suitable in some cases creating cavities on component surface is risky.

Inclusions

Intermetallic compound in zinc alloys can be created particular FeAl₃ is the most common compound of iron and aluminum.

With different colour than zamak alloy, these compound are tougher hence cause problems during phases of mechanical and finishing process.

Stress concentration and cracks can be created with components under mechanical fatigue.

Cold Laps

The most common die casting defects are cold laps.

Low temperatures and irregular flows are the causes of cold laps.

Wide selection of cold laps defects such as flow marks or lack of material are included.

Components can have a poor surface quality depending on defect rate or it can be incomplete in the worst case.

Matching two or more material flows generate phenomenon, due to low temperature, dirt inclusion, oxide formation and flows welding is incomplete/absent.

Laminations

During filling phase overlapping of two layers which are always separated generates laminations classified as part of cold laps category.

After die casting these defects are difficult to detect because they appear after finishing or pre-finishing operations.

The impact between inserts and casting during these phases causes subtle zinc layers lifting.

Other fluids and dirt of die casting process like lubricant or oil in the middle of these layers can be hidden.

During painting or galvanization surface treatment these substances can come out and worsen the outcome.

Blisters

Air inside the mould and machine is compressed during mould filling phase.

From the casting one part is ejected using vacuum valve, chill vent or overflows.

Inside the component air that remained can be dissolved with a homogeneous distribution inside the melted metal.

Air is concentrated due to many turbulences creating high pressure cavities.

Die casting defect is hidden and causes diminishing of component strength oftenly if there is no high temperature component extra operations.

Powder painting processes where the temperature is higher, gases inside the casting expand and bubbles are generated on the surface.

Cracks

Stress inside and outside the material causing material breakage are cracks.

During solidification and cooling phase the first ones are created.

In its natural directions it is not allowed to shrink.

Due to cavity geometry material resulting in residual stress inside the mould or deformations that can generate cracks after ejection.

From the mould or cutting phase during parts ejection external forces on components can be found.

Lakes

In aesthetical components these kind of defects caused by different solidification time of the filled metal are seen.

Different skin from the surface is generated in some part of the casting

fine grained area appears different from the rest.

How Do You Eliminate Defects During Pressure Die Casting Parts?

Gas porosity

• Make sure dry and clean metal alloy ingots.
• In case of overheating smelting temperature is controlled and degassing treatment done to molten metal alloy.
• Die casting parameters especially the injection speed be Chosed reasonably.
• Always make sure sufficient length of sprue and runner discharge easily In order to molten alloy flows stably and gases.
• At the positions that may form gas porosities set up venting launders and overflow launders using mold flow analysis software.
• Chose control spraying quantity and high quality mold release agent.

Inclusions

• Furnace charge purity ensured
• Thoroughly remove slags and purify metal liquid properly.
• Prevent involving slags Clean up the ladles.
• Die cavity Clean up.
• If mold release agent contains graphite, it must be mixed evenly and stirred.

Cold Laps

• Pouring temperature and die temperature is increased properly.
• Shorten filling time thus increase injection pressure.
• Injection speed and cross-sectional area of the ingate are increased.
• Die cavity venting condition is improved.
• To improve the fluidity choose proper metal alloy.
• Ensure flow of metal liquid is smooth in the die cavity.

Blisters

• Die casting injection speed and processing parameters are adjusted.
• Optimizing the gating system, add venting launders and overflow launders.
• To reduce the pressure effect of gas, adjust smelting process and lower die temperature of where the defects may occur.
• After spray prolong the blowing time and pressure-holding time.
• Optimize lubricant and the using quantity of mold release agent.

Cracks

• During smelting ensure correct alloy elements content.
• Die casting part structure optimized and non-uniform wall thickness avoided.
• Add ejection or adjust positions to ensure die casting parts balanced ejection.
• Core-pulling time or shorten opening time properly.
• Die temperature properly improved between 180° and 280° die working temperature.

Which Materials Are Suitable For Pressure Die Casting Parts?

Aluminum is with a share of more than 80 %, followed by zinc and magnesium one of the most important materials is Aluminum.

Materials like lead, copper, and tin can also be used with different alloys properties.

Is There Recommended Thickness For Material Die Casting Parts?

Within approximately 1s the surface of a typical aluminum pressure die-casting tool heats to 400–450˚C and cools to 150–200˚C within approximately 20 s.

What Is The Recommended Temperature For Pressure Die Casting Parts?

The alloy you intend to cast will determine the die temperature.

Stressing the die will lower the life expectancy of the die itself therefor avoid putting excess strain on your die.

At approximately 50° to 70° degrees higher than the crystallization temperature of the alloy pour your alloy into the die.

At approximately a third of the alloy’s temperature the die needs to be maintained.

What Is The Minimum Pressure For Die Casting Parts?

With a typical pressures around 0.7 bar the die is filled with metal from a pressurised furnace in low pressure die casting.

In the lower part of the vertical die casting machine the holding furnace is positioned with the molten metal.

It is injected directly upwards into the bottom of the mould.

How Can You Improve Efficiency Of Pressure Die Casting?

Weight Reduction

To significantly cut down the volume of metal for components is the main aim.

This helps the die caster save cost and weight in die casting.

If die casting component process used contains more metal.

Filling the die cavity and cooling the metal before ejection will take a considerable amount of time.

Adding Ribs

In order to increase the strength of component die casting companies often add ribs on thin walls die cast light fixtures.

To the suitable locations they will efficiently add ribs to accomplish the desired results.

Added ribs usually contain fillets in addition in the cross sections of the component to suppress the rapid changes.

Draft

During the die casting process all metals and components have a tendency to shrink.

Around 0.6 percent die cast light fixtures manufacturers reported the theoretical shrinkage by several professional.

The sections that project into the cavity shrinks allowing the casting to escape from the cavity and locks it.

To reduce the chances of shrinkage a simple way is to apply draft to the die casting component.

Uniform Cross Sections

To ensure that the cross sections of the component are uniform several experienced die casters put in extra efforts and time.

Flow of metal through the die is increased.

In the metal the sudden change in wall thickness may cause turbulence if the cross sections are not uniform.

Sliders

Holes that are parallel to parting line of the die avoiding undercuts will also increase the quality of the finished product.

To achieve these holes and undercuts sliders are used, they can be costly thus should be avoided if possible.

How Does Gravity Die Casting Parts Compare To Pressure Die Casting Parts?

In term of casting used by Nova Cast both are casting processes.

Metal mould into which non-ferrous molten metal usually Aluminum, Zinc, Magnesium, Lead, Tin or Copper alloy introduced are employed in both forms of Die casting.

gravity die casting parts

Gravity Die Casting and Pressure Die Casting difference is the way that molten metal arrives in the mould.

The molten metal is poured into the mould from gravity die casting above which fills purely under gravitational force from the bottom up.

The molten metal in pressure die casting is injected into the mould between 1500 and 25,400 psi under considerable pressure.

Until the casting solidifies this pressure is maintained.

In Pressure Die Casting the high-pressure filling of the die allows the alloy to be injected very quickly.

High productivity can be achieved coupled with the highly automated nature of the process while the potential for human error is reduced.

To fill the mould Gravity Die Casting relies on gravity the process is less suitable and slower to long production runs.

Requirement to deliver molten metal into mould under pressure in highly automated process makes Pressure Die Casting expensive and complex to set up.

A considerable difference in the tooling costs can be there for the moulds as Pressure Die Casting moulds need to be made.

From hardened Steel Pressure Die Casting moulds is made and will often require internal cooling channels to dissipate heat quickly.

Gravity Die Casting moulds can be made by contrast from Cast Iron and the lower cycling rates.

Heat build-up in the mould is prevented and rapid chilling of the casting allowed. Advantage of Gravity Die Casting is that sand cores can be used to create internal voids with Pressure Die Casting which are not possible.

In the quality of casting that can be achieved from each process there is a difference.

Is allowed to rapidly fill the mould under pressure to achieve very precise complex castings with thinner walls that are dimensionally accurate.

Very smooth cast surfaces which reduces secondary machining.

Gravity Die Casting can’t match these attributes that less folding and turbulence occurs.

This is due to slower speed at which molten metal enters the mould thus less air is trapped in the casting.

pressure die casting parts

Although Pressure Die Castings are stronger in as-cast state subsequent heat treatment casting is required hence advantage to Gravity Die Casting.

Due to casting process complexity Pressure Die Casting is considerably more expensive and less flexible to set up than Gravity Die Casting.

Pressure Die Casting is much better suited to stable potential for high productivity.

Where the unit can be very low cost of castings high-volume production will run.

Host of design specifications dictates the choice of casting process and geometry of component casted together with production run economic factors.

A project will be better suited and the right solution with Gravity Die Casting to Pressure Die Casting.

Additional Resources:

Die Casting

Hot Chamber Die Casting

Cold Chamber Die Casting

Gravity Die Casting

Low Pressure Die Casting

Vacuum Die Casting

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