High Pressure Die Casting: The Ultimate FAQ Guide

Probably, I know you want to learn more about high pressure die casting.

A reason this guide answers all your questions on high pressure die casting.

So keep reading to learn more.

What Is High Pressure Die Casting?

High pressure die casting is the process of forcing molten metal under pressure into sealed mould cavities.

You will use high pressure die casting to mould different metallic materials under high pressure using true die hydraulic machines.

Which Metal Alloys Are Suitable For High Pressure Die Casting?

High pressure die casting system

Well, there are numerous metal alloys that you can use for high pressure die casting depending on the final materials outcome.

Usually, you will use high pressure die casting for different types of metals which melt at high temperatures.

Here is a list of the common types of metals that you can mold using high pressure die casting method.

• Aluminium Metal Alloys
• Copper Metal Alloys
• Magnesium Metal Alloys
• Zinc Metal Alloys
• Tin Metal Alloys
• Lead Metal Alloys
• Carbon Steels Alloys
• Low-alloyed Steel Metals
• High-alloyed Steel Metals
• Tung-stem Steel Metals
• Chrome-molybdenum Steel Alloys

You can also opt for or use specific die casting alloys such as:

• Zinc Aluminium Metal Alloys to different aluminium association standards such as AA380, AA384, AA386, AA390 and AZ91D Magnesium

When Should You Choose High Pressure Die Casting?

You should choose high pressure die casting method to manufacture metallic moulds at a high speed.

Apart from that, you will choose high pressure die casting to manufacture precise or specific shapes.

In other words, it is the fastest and most reliable method for manufacturing durable and complex shapes.

In addition, you will choose high pressure die casting to accommodate stringent dimensional and appearance tolerance requirements.

As such, high pressure die casting is more suitable for meeting very high-quality moulding standards.

Additionally, you will choose high pressure die casting to achieve perfect and smooth surface finishes which can be textured.

Finally, you will choose high-pressure die casting method to produce relatively small or large metallic parts.

What Are The Disadvantages Of High Pressure Die Casting?

Despite the numerous benefits, you may also encounter a couple of limitations while using high pressure die casting.

As with any other forming process, high pressure casting present limitations that are impractical to specific applications.

Here are some of the limitations of high pressure die casting.

Operation Cost

You will spend relatively high start up and operational costs when using high pressure die casting method.

High pressure die casting dies are usually very complicated to make thus increasing the cost of production.

Slow On Thick-Walled Castings

You will have to slow down when manufacturing thick-walled metal castings using high pressure die casting methods.

The process requires additional time to dry and solidify thick-walled metal castings thus limiting the production speed.

Possibility Of Porosity

You may also run the risk of porosity through the high pressure die casting method due to presence of air pockets.

It may occur when selecting the wrong metal alloys, and during shrinkage of cast materials among others.

Limited To High-Fluidity Materials

You can only use high pressure die casting method on materials or metals that exhibit high fluidity levels.

In the long run, high pressure die casting results in materials that have low strength values than other methods.

High pressure die casting ollustration

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

You can either use high pressure die casting or low pressure die casting method to fill every crevice in die casting.

Here is a comparison between high pressure die casting and low pressure die casting methods.

High Pressure Die Casting

This is a faster die casting process which involves production of high pressure reaching about 150,000 kPa.

It produces high pressure on the device that enables molten metal to flow at a higher speed on a horizontal setup.

Low Pressure Die Casting

Low pressure die casting uses relatively small applied pressure ranging between 20 to 100 kPa.

It forces molten metal to move vertically into the mold in a slow but gradual climb from the furnace.

What Are The Components Of High Pressure Die Casting Machine?

High pressure die casting machine has numerous or several components that enable the high pressure die casting process.

Here are the main parts of the machine that enables or facilitates the manufacturing process.

High pressure die casting machine

• Casting cavity

The casting cavity is the space between the moving platen and the fixed platen where the molten metal alloy is cast.

• Moving Platen

The moving platen pushes the molten metal into the die cavity and releases it once it forms the right shape.

• Fixed Platen

The fixed platen is part of the die cavity that blocks the molten metal from passing through to the other parts.

It also helps in creating the final shape of the die by maintaining a solid press on the molten metal alloys.

• Injection Piston

The injection piston pushes the molten metal straight into the die cavity.

It produces high pressure that forces the molten metal straight into the die cavity at high speed.

• Ejectors

You will use the ejectors to eliminate or remove the formed die cast from the die cavity.

There are different types of ejectors such as vacuum or pressure ejectors that eliminate the final die cast.

• Die Cavity

The die cavity is the chamber or part of the machine that forms the shape of the final product.

You can have different shapes and sizes of the die cavity depending on the final product specifications.

• Cooling System

The cooling chamber is responsible for eliminating excess heat and solidifying the molten metal.

It uses water as the main cooling agent to eliminate excess heat from the molten metal.

• Feeder Channel

You will use the feeder channel to feed or push the molten metal into the die cavity.

It acts as a gate or a path for the molten metal to flow into the die cavity for moulding.

How Does High Pressure Die Casting Process Work?

You can use the high pressure die casting method or machine to make anything out of metal alloys.

While there are numerous ways of performing high pressure die casting method, there are four main steps to follow.

Here are the four main steps you can follow to successfully operate the high pressure die casting machine.

Step One: Mold Preparation

Firstly, you will begin the process by preparing the mold by lubricating the internal parts of the machine.

You should consider lubricating the internal parts of the machine to regulate the temperatures during the manufacturing process.

Apart from that, the lubricant creates a film between the mold and the molten metal thus facilitating easy removal.

You should also prepare the molten metal alloys using the materials that will suit your final requirements.

As soon as you complete the process, you will power the machine in preparation for the die casting process.

Step Two: Injection Process

Secondly, you will proceed with the injection or introduction of the molten metal alloys after preparing the mold.

At this point, you must make sure that the mold is completely closed and sealed to prevent leakages.

Apart from that, you must close and seal the mold to allow or accept the highly pressurised molten metal.

Depending on the application specifications, you may inject the molten metal into the mold at a pressure between 1500 to 25000 Psi.

The machine will maintain the specific pressure until the molten metal cools and solidifies.

Step Three: Cavity Ejection

As soon as the molten metal alloy solidifies and cools down completely, you will eject it from the mold.

You will engage the ejector pins to release the cavity from the mold.

At this point, the cavity is in a solid form thus facilitating easy ejection from the mold.

All the high pressure die casting machines are programmed to eject the cavity when it solidifies.

Step Four: Shakeout

Finally, you will complete the process of high pressure die casting by conducting a shakeout.

You will remove any scrap metal that may stick to the cavity using different scrapping methods.

It is common for different cavities to accumulate excess scrap metal during the die casting process.

Apart from that, there are other scrap metal pieces that remain within the mold that must be removed.

You will remove all the scrap metal remains within the mold before reusing the mold.

How Can You Increase Efficiency Of High Pressure Die Casting Process Flow?

You can increase the efficiency of the high pressure die casting process flow by making a few adjustments.

Here are some of the methods that you can use to increase the efficiency of high pressure die casting process.

• Quantify Everything

You can increase efficiency of high pressure die casting process by ensuring that all the quantities are properly measured.

A proper mixture of the metal alloys will create a fluid that can flow easily thus boosting process flow.

• Improve Training or Hire Professionals

You should consider hiring trained personnel with plenty of experience in handling the high pressure die casting process.

Apart from that, you can also train the personnel within your reach to improve their skills.

• Weight Reduction

You should reduce the weight of the metal alloys to optimum levels to maximize the flow of the metal alloy.

Apart from reducing weight, you will also save cost in the high pressure die casting process thus boosting production efficiency.

Which Defects Are Common During High Pressure Die Casting Process?

During the casting process, there are possible defects that you may experience.

Here are the common defects and their causes that occur during high pressure die casting process.

• Flash Defect

The flash defect occurs when the injection pressure is very high and the clamp force is too low.

• Unfilled Sections

You may also have unfilled sections due to insufficient shot volume, low pouring temperatures, and slow injection.

• Bubble Defects

It is common to see bubble defects when the injection temperature is too high causing non-uniform cooling rates.

• Hot Tearing Defects

Hot tearing defects are common in the die casting process due to non-uniform cooling rates.

• Ejector Marks Defects

You may also have ejector marks when the cooling time is too short and the ejection force is too high.

How Can You Prevent Defects During High Pressure Die Casting?

Stages in high pressure die casting

Well, you can prevent defects during high pressure die casting process by sorting out the malfunctions.

Here are some of the ways that you can explore to prevent defects during high pressure die casting process.

Controlling And Balancing The Parameters

You can prevent defects such as the flash defect by balancing the injection pressure and the clamp force.

In other words, you will reduce the injection pressure and increase the clamp force.

You can also prevent unfilled sections by increasing shot volumes and speed of injection.

Apart from that, you can increase the pouring temperature to solve the unfilled sections.

You can also balance the cooling rate and reduce injection temperature to eliminate bubbles.

In addition to that, you should control the cooling time and ejection force to eliminate the ejection marks.

Can You Make Complex Parts With High Pressure Die Casting?

Yes, you can make complex parts with the high pressure die casting machine.

It is the most suitable method that will fit every crevice and nuke of the mold thus preventing leakage.

It is capable of accommodating stringent requirements for dimensional tolerance and appearance thus suitable for making complex parts.

Some of the parts that you can make using the high pressure die casting method include:

• Engine Blocks
• Gearbox Casings
• Oil Sumps
• Engine Mounts
• Other Structural Parts

What Is The Recommended High Pressure Die Casting Pressure Range?

You should maintain a recommended high pressure of about 150,000 kPa when using high pressure die casting.

The recommended pressure is high enough to press the molten metal alloys to create the desired shape.

You have to ensure that the pressure is constants throughout the solidification phase to eliminate potential defects.

Apart From High Pressure Die Casting, Which Other Techniques Can You Use To Make Parts?

There are other methods that you can explore to make complex parts, other than high pressure die casting.

Here are the common methods that you should consider exploring when making the high pressure die casting.

·         Squeeze Die Casting Process

You can opt for the liquid forging or squeeze die casting process to combine permanent mold casting with die forging.

It is a single step where specific amounts of molten alloys are poured in lubricated and preheated die.

Finally, it is forged and then solidified under very high pressure to form the desired casting shape.

·         Vacuum Die Casting Process

You can also opt for vacuum die casting process by injecting molten metal under extreme pressure into a steel die.

It has a vacuum assisted system that draws in the short sleeve and mold cavity before injection mold occurs.

·         Semisolid Casting Process

You may opt for the semisolid casting process that combines forging and casting together.

It depends on the sheared flow of thixotropic fluids and solidification while fluid is standing.

How Does Hot Chamber Die Casting System Compare To Cold Chamber Die Casting System?

You can either opt for the hot chamber die casting method or the cold chamber die casting system.

The hot chamber die casting method heats the metal alloys inside the casting machine during the formation process.

In this case, the machine has the heating chamber that heats and melts the metal within the machine.

On the other hand, cold chamber die casting method involves hating the metal alloys outside the machine.

In other words, you will have a separate heating chamber for melting metal alloys before casting on the machine.

How Can You Reduce Cost Of High Pressure Die Casting Process?

You can explore different options to reduce the cost of high pressure die casting process.

Here are some of the tricks that you can explore to reduce the cost of high pressure die casting.

Breaking Don The Cycle Time

You can break down the cycle time into resetting time. Cooling time, and injection time.

After that, you will reduce every time category thus reducing the overall time of production and cost.

Purchasing In Bulk

You can reduce the cost of high pressure die casting process by purchasing all the raw materials in bulk.

In this case, you will factor in the economies of scale to reduce the cost of high pressure die casting process.

Conduct Mold Flow Analysis

Analysing the mold flow will help in identifying the pitfalls within the high pressure die casting process.

You can solve the pitfalls within the process to enable a smooth transition thus reducing the production cost.

Use Core To Lower Mold Costs

You can also use the cores that require minimal modification to reduce the overall cost of high pressure die casting process.

Instead of eliminating or throwing away molds, you can simply modify them thus saving on the cost of new purchases.

Which Value Added Operations Can You Apply On High Pressure Die Cast Parts?

You should apply value added operations on high pressure die cast parts to improve surface finish.

A proper surface finish comes with numerous benefits that increase appearance and functionality of the final product.

Here is a list of some of the value-added operations that you can apply on high pressure die cast parts.

Mechanical Finishing

Mechanical finishing encourages improved appearance, wettability or adhesion, corrosion resistance, chemical resistance, tarnish resistance, hardness, and overall wear resistance.

Decorative Finishing

You should also consider decorative finishing to enhance component appearance with texture, colour, and lustre.

Functional Finishing

You should opt for functional finishing to improve the function ability of the final product.

The most common functional finishes are durable press antistatic, antimicrobial, UV protection, self cleaning, flame retardant, and water repellent among others.

Where Can You Use High Pressure Die Casting?

You can apply the high pressure die casting method to make numerous casts in different industries.

Some of the common industries that depend on high pressure die casting method are:

• Automotive Industry
• Aeronautic Industry
• Mining Industry

What Is The Recommended Tolerance For High Pressure Die Casting?

The recommended tolerance for high pressure die casting will depend on the metal alloys.

For instance, the recommended tolerance for high pressure die casting in aluminium is:

• Standard: +/- 0.010 inch per 1 inch — then +/- 0.001 inch for each additional inch
• Precision: +/- 0.002 inch per 1 inch — then +/- 0.001 inch for each additional inch

For all your high pressure die casting needs, Inox offer perfect solution for you – contact us now.