I also see die-casting applications in the wind power, solar and battery storage sectors

FP: Steve, we’ve known each other for a very long time – how has die-casting changed during your term of office?

SU: Thomas, yes, we’ve known each other for almost three decades, and it’s been a great pleasure to have got to know you!

During my career at NADCA, a great deal has changed in die-casting, and it will continue to change. That’s why it has been so exciting and interesting over the years. Variations on standard die-casting have been developed into viable processes such as squeeze casting, semi-solid metal (SSM) processing/casting and vacuum die-casting. These processes were developed to produce die-cast components with higher strength that are heat-treatable and weldable. Then super-high-vacuum die-casting came into play with the advent of what is now known as structural die-casting. Structural die-cast components, as the name suggests, are used for genuine structural applications and are crash-worthy due to the high ductility that can be achieved.

Over the years, the development of alloys has further improved the performance of aluminium, zinc and magnesium die-cast components. For example, strength, ductility and temperature resistance have been improved in each of these three alloy families. Thanks to process improvements and new alloys, standard die-cast components made from aluminium alloys can now be produced in such a way that they are heat-treatable and weldable, whilst also exhibiting higher ductility.

New die-casting materials have been developed to extend the service life of die-casting moulds through improved impact strength and thermal fatigue resistance. New die coatings have been developed to facilitate brazing and significantly reduce the use of spray nozzles – and in some cases even eliminate the need for spray nozzles in certain areas of the die. Additive manufacturing (AM) processes have matured to such an extent that die-cast components with complex cooling channels are now produced using AM to improve thermal management in the die-casting process.

Computer modelling has evolved from a rough flow simulation into an extremely useful and precise tool for the design of castings, moulds and processes.

An even more marked change can be observed in the size of die-cast components, as die-casting machines are constantly increasing in size. Two decades ago, a 2,500-tonne machine was considered large. Then came 4,000-tonne machines; a few years ago, 8,000-tonne machines became a reality, followed by 9,000-tonne machines. I’m not sure where this will end, or what might come after the ‘giga-presses’.

Today, we also have Industry 4.0, smart manufacturing and machine learning. So a lot has changed, and technological progress continues!

FP: Are there differences between the major markets – the US and Mexico, Europe and Asia?

The largest market for die-casting in the US and Mexico is the automotive industry, followed by the housing market. The largest market for die-casting in Europe and Asia is also the automotive market. I suspect that the housing sector is the second-largest market, which is also served in Europe and Asia.

FP: The development of ‘giga’ or ‘mega’ castings was initially met with scepticism, but we are now witnessing a boom, as we are hearing not only from China but also from Europe and the US.

Is this a trend exclusively for OEMs, or does it also make sense for Tier 1 or Tier 2 suppliers?

That is a very good question, and OEMs as well as Tier 1 and Tier 2 suppliers are grappling with this issue. What makes the matter difficult is the scale of the investment required to manufacture giga or mega castings. There are only a few suppliers who can afford the necessary capital outlay, and those who can want to be sure that the investment will yield an appropriate return. This return depends on the volume of the giga-casting business, and suppliers would like to see a guaranteed level of business or for the OEMs to share in the investment costs. With such a guarantee and/or a share in the investment costs, it can also make sense for Tier 1 and Tier 2 suppliers, as well as for OEMs. A supplier who decides to invest without a guarantee or a share in the investment costs is aware of the associated risk, and there are very few such suppliers.

FP: In your opinion, where does the natural or optimal physical or metallurgical limit lie for large structural components?

SU: We have already surpassed what I would have considered the limit a few years ago. The industry has succeeded in overcoming the limitations of machine size, casting weights and flow paths. Concepts such as dual-shot sockets or multi-shot ends, which feed moulds the size of an entire vehicle body, could come into play in the future and push beyond today’s limits. So perhaps our imagination really is the limit!

FP: Do you also see alternative applications for other components, perhaps even outside the automotive industry?

Absolutely. Another recent development in die-casting is the focus on sustainability. And with sustainability comes renewable energy. For example, there are opportunities for die-casting applications in the fields of wind power, solar energy and battery storage.

FP: What developments are emerging for die-casting and permanent mould casting in general; what can we expect in the future, and what technical developments do you see on the horizon?

Here are some developments that are emerging on the horizon.

• Additive manufacturing of ever-larger moulded parts as well as moulds for permanent mould casting processes.
• On-demand melting of alloys on a shot-by-shot basis for die-casting or on a casting-by-casting basis for gravity casting processes.
• Die-casting of high-temperature materials such as steel, nickel and titanium.
  
  

FP: Do you consider rheocasting, thixoxcasting, thixoinjector casting or other formats to be an interesting development?

Yes. These semi-solid metal processing methods offer significant advantages, such as a longer mould life, a shorter solidification time, good filling, strength and excellent properties. As castings produced using these processes are slightly more expensive than those produced by conventional die-casting, it is important to capitalise on the benefits they offer in terms of the end product’s cost-effectiveness. In some cases, a machine with a lower tonnage can be used to produce a part than a standard die-casting machine. This can help to reduce the cost of the part and thus improve cost-effectiveness.

FP: The US and Mexico appear to be very well positioned in the field of light metal die-casting at present. Is this a general trend or a side effect of the IRA?

I believe this is a general trend driven by market demand. Furthermore, more and more companies are looking for die-casters located close to their production facilities. Whilst supply chain issues have largely been resolved, there are still concerns about future problems. The ongoing tariffs have also helped to level the playing field somewhat. Finally, the desire for a closer supply base is advantageous when it comes to design or production-related changes.

FP: For many people, the USA is still the land of opportunity. What will mobility in America look like in 20 years’ time?

Mobility in 20 years’ time will be highly electrified and autonomous. Passenger cars will be electric and/or fuelled by fuel cells and will be self-driving. Everyone in a vehicle will be a passenger (no driver), simply setting a destination and enjoying the journey from point A to point B. The seats will be adjustable to ensure privacy, or they will face each other so that groups can meet or chat whilst travelling. There will be dedicated lanes on roads and motorways suitable for autonomous vehicles. Air travel is also likely to be autonomous. To support this technology, significant investment will need to be made in infrastructure, such as motorways and charging stations.

FP: All the best to you, Steve – thank you very much for your excellent collaboration, and we wish you much joy and good health for the future. And welcome, Mike. Foundry-Planet wishes you a great start and good luck!

Thomas, thank you very much for the opportunity to share these insights with Foundry-Planet.