Additive manufacturing (AM), better known as 3D printing, has introduced a fresh approach to production. Instead of chiselling away at a solid block like subtractive manufacturing, AM builds parts layer by layer from digital designs. Sounds futuristic, right?
With techniques like fused deposition modelling (FDM) and direct metal laser sintering (DMLS), 3D printing can craft intricate shapes that might leave traditional methods scratching their heads.
But hold on—before we write off subtractive manufacturing as the dusty relic of engineering, let’s get one thing straight: AM isn’t here to take over. Subtractive methods like CNC machining still hold a solid place in manufacturing for good reason. It's just that now, with AM in the mix, engineers have more options at their disposal.
Additive manufacturing has been making waves in industries ranging from aerospace to medical devices. Its ability to create complex geometries, reduce material waste, and offer rapid prototyping has allowed it to carve out a space in applications where traditional methods struggle.
But that doesn't mean it's an outright replacement. It’s more of a new teammate with its own set of strengths and weaknesses.
As technology advances, we could see AM become more widespread, but it’ll likely be used where it shines best—alongside CNC machines, not against them.
Additive manufacturing allows for designs that would be impossible or incredibly expensive to achieve with subtractive methods. Hollow structures, lattice designs, and internal channels? No problem for AM. This is where 3D printing really shows off, especially in fields like aerospace, medical, and motorsport, where many components need to be lightweight, intricate, and customised.
But—and it’s a big but—subtractive manufacturing remains crucial when producing large quantities of components or where parts require material properties that additive methods still can’t handle. So, while AM might seem like the hero of complex shapes and groundbreaking parts, subtractive manufacturing is quietly keeping the world turning in the background.
AM’s ability to enable lightweight, optimised structures is a game-changer, especially in the aerospace and automotive industries, where every gram counts. Engineers typically use topology optimisation—basically finding the best shape for performance with the least material—to ensure parts are designed to be strong yet lightweight.
But again, it’s situational. Traditional methods are still essential for creating parts with materials or properties AM can't match yet. The idea isn’t to replace subtractive methods but to bring a new option to the table.
In subtractive manufacturing, there’s often significant material waste—cutting, grinding, and drilling your way through a block of material until you have your part. Additive manufacturing flips this script by only depositing material where it’s needed, reducing waste and potentially lowering material costs. AM also enables businesses to lower inventory needs by only printing replacement parts or components when needed, rather than keeping warehouses full of stuff.
However, AM is highly energy-intensive and processes that use powders create highly volatile and dangerous waste products. We’re also seeing CNC processes become more and more efficient with time thanks to advancements like near-net shapes, tooling developments, and machine advancements.
AM excels at customisation. Whether it’s bespoke medical implants or industrial components tailored to specific tasks, 3D printing allows for changes without expensive retooling. This makes it an excellent choice for one-off parts, small production runs, or part consolidation. However, there are some AM processes (like Laser Powder Bed Fusion), where engineers will only find performance benefits when parts have been convinced and designed with AM in mind.
For mass production of identical parts, subtractive manufacturing is hard to beat. If you need 10,000 identical metal components, CNC machines are likely going to remain the go-to. AM is great for flexibility, but there’s room for both in the workshop.
Additive manufacturing really shines in the prototyping phase. Engineers can design, print, and test iterations of a product within days, speeding up the development process significantly. That ability to create functional prototypes quickly can shave weeks off the design-to-market timeline.
Yet, once the prototype is finalised, switching to subtractive methods for mass production might still be more efficient. AM helps get things moving, but when it comes to volume, CNC and traditional manufacturing methods could still take the lead.
Additive manufacturing is great, but it’s still catching up when it comes to the variety and strength of materials. While metals like titanium can be printed, AM is still not viable for some performance materials that traditional methods work great with. In addition, some 3D printing materials, especially metal powders, are also prohibitively expensive, challenging to store, and hard to dispose of.
So, while AM could continue to expand its material repertoire, don’t expect it to handle everything that CNC and subtractive methods do—at least not just yet.
While AM is becoming more affordable, especially for small-batch or complex parts, the upfront costs can still be high. The machines, especially for metal printing, aren’t cheap, and neither are the materials. For high-volume production, subtractive methods are pretty much always more cost-effective, unless the printing process offers specific and niche material properties.
That said, as technology advances, the cost of AM could come down, especially for custom or low-volume parts. But again, it's all about choosing the right tool for the job, not abandoning traditional methods altogether.
Additive manufacturing can be slower than subtractive methods, especially for larger or more detailed parts. Building an object layer by layer takes time, and while AM is great for intricate designs, it can take hours or even days to finish. Traditional methods might still outpace AM when it comes to high-volume, simple parts.
Plus, AM often requires post-processing (e.g., removing support structures or smoothing surfaces), which adds time to the production cycle. In the end, it’s about balancing speed with complexity.
Metal additive manufacturing is making strides, especially in high-stress industries like aerospace and medical. Techniques like Selective Laser Melting (SLM) are allowing for the creation of high-performance parts that can withstand extreme environments while offering significant performance beneifts. While CNC machining still has the edge for large-volume metal parts, metal 3D printing could find its niche in producing complex, custom components like personalised implants and rocket componentry.
Bioprinting is another exciting frontier in additive manufacturing. Researchers are exploring the possibility of printing biological structures like tissues and organs. While still in its early stages, this technology could eventually revolutionise healthcare. That said, it’s still very much a “could,” and traditional manufacturing will continue to dominate most industries for the foreseeable future.
This emerging trend could allow parts to change shape or function over time in response to environmental stimuli. While this sounds straight out of science fiction, it could eventually have applications in fields like adaptive structures and self-repairing components. But again, we’re not there yet—don’t expect to see your CNC machine packing up anytime soon.
The future of manufacturing isn’t a winner-takes-all scenario. It’s more of a team effort. Additive manufacturing will play an increasingly important role, especially in areas where customisation, complexity, or material efficiency are critical. But subtractive manufacturing, with its precision and broad material capabilities, will continue to be essential.
Rather than one replacing the other, the most likely scenario is a collaboration between the two, with engineers using each method where it makes the most sense. As additive manufacturing continues to develop, its role could expand, but it will remain just one part of a diverse manufacturing repertoire.
Additive manufacturing is revolutionising production, but it’s not the be-all and end-all of manufacturing. It excels in areas like complexity, customisation, and material efficiency, while subtractive methods still reign supreme when it comes to speed and high-volume production.
So, while additive manufacturing will continue to make its mark on the industry, don’t count traditional manufacturing out. The future lies in knowing when to use which tool, creating a more flexible, efficient, and innovative production process for the engineers and manufacturers of tomorrow.