There are numerous manufacturing processes available that produce high-quality metal components, including aluminium die casting and screw machining.

But what’s the difference between the two, and which is best?

Let’s take a look…

What is die casting?

Die casting is an industrial manufacturing process utilised to create a series of uniform metal components. There are various die casting methods including pressure and gravity casting, but the most prevalent is aluminium die casting, which we’ll focus on throughout this blog.

Aluminium die casting involves molten aluminium alloy being injected under high pressure and speed into moulds (dies), which consist of two halves that clamp together when in the die casting machine.

After the liquid metal has cooled and hardened, the die is opened and the casted metal part is ejected.

What’s screw machining?

Also known as screw casting, screw machining uses an automated lathe machine and attached cutting tools to shape new components.

This works by rotating a metal bar stock on the lathe, and using the cutting tools, which are set at various angles, to shave excess material, leaving behind the desired shape.

Screw machining can be used to create intricate metal components for various uses, and is frequently used to craft threaded parts, such as nuts and bolts.

Pros of die casting

High volume production – the die casting process is ideal for mass-producing metal parts rapidly. Sometimes, 10,000 metal parts can be formed per hour in die casting machines. This ultimately means that more components are gained quickly.
Dimensional accuracy – complex and accurate shapes can be created using die casting. The high-pressure injection of the molten metal completely fills the die cavity, forming a perfectly intricate and precise cast.
Repeatability – die casting forms a series of uniform metal parts as the same steel mould is used throughout one production cycle. Consistent components are essential for smooth functioning and aesthetic purposes.
Surface finish – parts produced from aluminium die casting techniques typically have a higher quality surface finish. This is due to the machine’s temperature and pressure controls. Surfaces play a significant role in aerodynamics, which is why this process is utilised frequently by the aviation industry.
Cost-effectiveness – as thousands of metal instruments can be formed during one die cast production run, this process is most cost-effective for mass manufacturing.

Cons of die-casting

Slower lead times – as intricate die cavities need to be designed before production takes place, receiving metal parts could take longer. However, the die casting process itself is impressively efficient once the mould has been made.
Higher upfront costs – die casting processes have a more costly initial set-up cost than screw casting due to the cost of creating the mould.

Benefits of screw casting

High-precision parts at a low volume – screw machining is an excellent method for producing precise parts with tighter tolerances.
A top choice for steel parts – steel parts aren’t usually manufactured using die casting as they can fuse with the steel mould cavity – that’s why screw casting is a good alternative in these cases.
Low initial tooling cost – this manufacturing method has a much lower tooling cost. This is because, unlike die casting, no high-pressure injection machinery or custom mould is required.

Disadvantages of screw machining

Material waste – to form metal items using screw casting techniques, most of the metal workpiece is shaved away in the process. In reality, manufacturers are investing in large quantities of metal that aren’t used to craft components.

Slower production times – although slow screw machining processes result in pieces boasting excellent tolerances, it rapidly slows production times and raises manufacturing costs. Die casting parts still offer exceptional tolerances but with the added bonus of fast production.
Not cost-effective for high-volume manufacturing – whilst screw casting has a lower tooling cost, it has a much higher cost per part during high-volume production runs.

Which is better: die casting or screw casting?

Overall, the benefits of aluminium die casting outweigh those of screw machining.

Although screw machining has a lower tooling cost, die casting is more economical in the long term.

Plus, screw machining is only more suitable for small runs as it’s a much slower process and simply isn’t cost-effective for large runs. What’s more, the process involves significant amounts of material wastage, which isn’t very economical for your business.

Enquire about metal part production today

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If this is you, don’t hesitate to get in touch with our expert team today and they’ll help you in any way they can.