Metal components: a guide to hot chamber die casting

Lay flat of metal components made by hot chamber die casting

Read time: 5 minutes | Published on: 18 September 2023

Insights

The market for metal components is expected to grow by more than 8% (compound annual growth rate) between 2023 and 2030. Though the tooling costs and volatility of raw material prices may restrict this growth, the relatively low cost of producing complex parts through hot chamber die casting makes the process increasingly popular.

Die casting to make metal components a cost-effective manufacturing process, well-suited for high volume production. It is also a sustainable process that produces minimal waste. So how does this process work, what type of die casting technology is used, what are the benefits and the features you need to look for in a metal components manufacturer? This article will answer all these questions.

What is the process for hot chamber die casting?

Hot chamber die casting is a manufacturing process that uses alloys with a low melting temperature to create parts. Metal is heated within the casting machine and the molten metal is poured into a die cavity (this mould is known as a holding chamber). Pressure is applied using a plunger to force the metal into the shape of the die. This casting is held under pressure for a precise period of time, during which it cools and solidifies before being removed from the die. This is achieved by removing the plunger and ejecting the casting from the die.

Although the hot chamber die casting process can produce thousands of components every hour, it takes experience to make high quality components this way. This is because there are several steps involved in creating die casted parts, with tight technical controls that need to be in place.

At Essentra, we have extensive expertise in using hot chamber die casting to make a wide range of metal components, with a huge range of mould designs. We melt Zamak or aluminium ingots and inject them in a mould to cool and thus create the parts. The mould plays a key part in the final quality of the component.

As Ugur Buyuk, Global Head of Technical Access Solutions at Essentra, explains: "The mould design is paramount in meeting the demands of quality and speed. A well-thought-out design that minimises waste and maximises cavity utilisation is essential. This approach, using the latest technology, ensures that the production process is efficient."

This process is not be confused with dip moulding which is a process to create plastic parts.

What are the advantages of die casting?

Hot chamber die casting is an ideal process to produce a large range of strong, high quality metal components for a number of reasons:

It has fast cycle times so is an efficient process. This is because the metal is kept molten between castings, rather than being melted each time.
High volume. Experienced manufacturers, such as Essentra, can set up the process to create precise parts that are accurate to tight tolerances, meaning customers can be sure they're getting components with the material properties they need..
Good surface finish. Hot chamber die casting can produce parts with a good surface finish. This means there is no need for extra finishing operations, such as grinding or polishing, reducing further potential cost.
Non-shrinkage. Die casted parts don't shrink in size throughout the process, as some metal injection moulded components do.

Essentra metal components including hinges and quarter turn spring latch

What are the alternatives to hot chamber die casting?

Metal components can be manufactured in a number of ways, each with their own advantages and disadvantages.

Cold chamber die casting

The cold chamber die casting process is necessary for metals with a high melting temperature. The metal needs to be liquified in a furnace which is separate to the moulding machine and then is transferred into a cooler chamber where it is injected into the casting machine.

There are advantages to cold chamber die casting which include denser castings as higher injection pressures and speed can be applied during the process. There are disadvantages too. It is a more expensive process as the machines are larger, cost more to run and have slower cycle times.

Metal injection moulding

Metal injection moulding uses powders rather than molten metal and has to go through four distinct processes in its manufacture.

Metal powder is mixed with a thermoplastic binder and turned into pellets.
These ‘feedstock’ pellets are injected into an injection moulding machine (much like the plastic injection moulding process to create the desired shape. The mould is then cooled to solidify the feedstock.
Via a thermal or chemical process, the plastic (binder) is removed from the moulded part. This is known as debinding.
Sintering is the last stage. The part is heated to a high temperature to fuse the metal particles together.

Vacuum die casting

For metals that might be affected by gas porosity or complex-shaped components that feature very thin slivers of metal, introducing a vacuum into the die casting process can be very beneficial. The vacuum clears any gas/air out of the cavity before the molten metal is injected into the mould.

Disadvantages of hot chamber die casting

It is imperative that you look for experienced components manufacturers with excellent safety records, when ordering hot chamber die cast components. Does your supplier have the knowledge and expertise to control the temperature of the molten metal? If not, the quality of the component can be compromised and it is a dangerous process.

Also, due to the need for metals that melt at low temperatures, it is not appropriate for all metals and alloys.

Best practice for hot chamber die casting

There are two critical factors original equipment manufacturers (OEM) need to be aware of before choosing a metal components manufacturer, says Ugur Buyuk.

“The first is effective mould design and quality. The design is paramount in meeting the demands of quality and speed. A well-thought-out design that minimises waste and maximises cavity utilisation is essential.

“The second is having high efficiency machines,” he continues, “as the choice of die casting machines significantly impacts the outcome.

“While there are various machine brands available, only a select few offer both efficiency and top-notch quality. At our MESAN facility in Istanbul, Turkey, we use machines from such manufacturers as Frech, who are renowned for both traits.”

“We look for machines that allow the widest selection of materials possible for this sort of die casting, as well as ones that permit the molten metal to flow evenly into the die and avoid defects. Then we train our teams extensively to correctly control the process parameters, such as injection pressure and cooling time.

Ugur concludes: “By emphasising these two crucial aspects - meticulous mould design and the use of efficient machinery - we ensure that our metal die casting processes are optimised for quality and speed, meeting the highest standards of performance and customer satisfaction."

Essentra’s Mesan factory in Turkey, producer of metal components

What are the challenges in hot chamber die casting?

Any metal injection moulding process, whether using molten metal or powders, come with their unique challenges, primarily revolving around issues such as flashing and porosity. However, our team of experts effectively addresses and mitigates these challenges through a combination of strategies, says Ugur.

“By combining these factors - meticulous mould design, state-of-the-art machinery, and a skilled team – we effectively mitigate challenges like flashing and porosity in metal hot chamber die casting, ensuring that our products meet the highest standards.”

What products are made using hot chamber die casting?

Hot chamber die casting is used to produce strong, durable and reliable components such as:

By making it possible for manufacturers to produce injection moulding metal which is high-density and complex components at scale, hot chamber die casting production also makes these metal products more affordable for customers.

View our range of metal hardware components

Essentra metal hot chamber die casted parts

How to find the right metal components manufacturer

To make sure you're getting high quality die casted metal parts, you need to find an experienced manufacturer with a strong heritage in this area. This will ensure the components you're buying are consistently strong, reliable and durable and the manufacturer has the capability to deliver at high volume.

Essentra’s largest metal component manufacturing facility is situated in Istanbul, Turkey and serves a major production hub. It has been at the forefront of the access hardware business for four decades, making it a leader with over 45 years of experience.

Another significant location for our metal components operations is in Yichun City, China with 30 years’ experience of producing access hardware.

Essentra can also offer:

Experts who prioritise the efficient design and engineering of moulds to minimise issues such as flashing
High quality and efficient injection moulding machinery which help to reduce part faults with precise and reliable performance
Cutting-edge technology that's seamlessly integrated into operations and allows for tight controls over the injection moulding metal process
A large and very experienced engineering team with a wealth of knowledge and expertise in fine-tuning the metal components manufacturing process.

This means when you choose metal components from Essentra, you can guarantee that you're getting high quality metal parts.

The expert team at Essentra are knowledgeable in all aspects of die casted metal components. They are always available to answer any questions, source samples and provide in-depth data on both current products and bespoke opportunities.