The manufacturing world can feel like a boxing ring. With constant changes, some of the most reliable technologies have suddenly become rival opponents fighting to make it on top. Two notable candidates gunning for the prize are 3D printing and CNC machining — each trained and ready with their strengths and capabilities.
CNC machining vs 3D printing. It’s a clash of the titans, a battle of technologies. Both are well-regarded and used to craft various components for an array of uses, but who will win?
CNC vs 3D printing: the weigh-in
It’s essential that we meet the competition before anyone pulls out the boxing gloves and starts swinging.
In the blue corner, we have CNC machining, known for its speed, accuracy, and strength. In the red corner, 3D printing waits, backed by its flexibility and design freedom.
You might already know the difference between a CNC machine and a 3D printer. If you don’t, you might be asking yourself, is a 3D printer a CNC machine? The simple answer is no. Although they share similar workflows, their processes and production methods are actually quite different.
However, to contrast CNC machining with 3D printing, we first need to compare additive and subtractive manufacturing as each contender takes a different stance.
Additive manufacturing involves adding layers to create an item. Subtractive manufacturing, on the other hand, involves chipping away at a block of material. These processes have their own advantages and disadvantages, different outputs, and different possibilities when it comes to geometry and precision.
So, what is a CNC machine?
Many CNC machines are available, including lathes, milling, and laser machines. CNC stands for computer numerical control, meaning a computer controls them. CNC machining is a type of subtractive manufacturing. It lets you make shapes and parts from blocks or rods of material using coded, programmed instructions. CNC machines’ high precision and repeatability make them popular in many industries, including aerospace and automation.
What is 3D printing?
3D printing, on the other hand, is an additive manufacturing process. This means there’s no need for a block of material or a mould. Instead, 3D printing layers the material to form the component. The engineering industry employs 3D printing pretty frequently for rapid prototyping and lightweight geometries. In particular, though, it’s ideal for industries such as aerospace, medicine, and dentistry.
While CNC machining and 3D printing have different manufacturing processes, that doesn’t mean they aren’t evenly matched opponents in terms of quality in their respective divisions.
Round one
The gloves are on. CNC machining throws the first punch with its dimensional accuracy and precision.
Since it allows you to manufacture parts and components to tight tolerances, they can meet the required standards and regulations. CNC machining is compatible with various materials, including wood, metal, composites and plastics, and it is ideal for crafting parts from materials unsuitable for other methods.
It’s no surprise that CNC machining has a solid left hook — it’s a perfect option for large parts and large quantities. It offers an effective way of producing multiple components while keeping costs low, a well-established technology that can be relied upon across various industries, and automated manufacturing processes that limit human error and prevent the associated waste.
Round two
Thanks to its accuracy and speed, the crowd goes wild when 3D printing gets in a solid jab.
3D printing has been used across multiple sectors, offering freedom of shape and design. It can create a range of complex parts with custom designs to tight deadlines while remaining cost-effective, deeming it perfect for rapid prototyping — making parts quickly and easily and, technology permitting, to almost any geometry without additional costs and tooling.
It’s in an equal weight class to CNC machining. Despite its strong focus on plastics, it’s becoming increasingly compatible with other materials, such as metals and composites.
Round three
3D printing and CNC machining are trading blow for blow. The ring-side judges take this time to confer. Who will win?
While both contenders are strong, they also have their weaknesses.
3D printing may be versatile, but its components aren’t fully dense once finished. They’re anisotropic, which means they don’t have the materials or mechanical properties of parts made with subtractive or formative processes. Conditions can fluctuate when cooling or curing, resulting in prints of the same part varying slightly. As a result, volumes above ten may be less consistent.
The judges speculate that 3D printing is more accessible than CNC machining in terms of operation. Once the file is prepared, all that’s left to do is choose the part orientation and any required supports. You also don’t have to supervise the printing process. It is well worth remembering that CNC machining is a much more experienced fighter with skilled trainers in its corner. CNC machining typically requires a lot more prep and operation. Skilled operators have to choose the appropriate tools, select cutting paths and rotation speeds, as well as monitor the process and reposition materials when necessary — though this depends on the machine and can vary.
You must also consider any time-consuming post-processes, which isn’t always the case with 3D printing but is more common in CNC. Not only this, but CNC machining doesn’t allow for hollow geometries or undercuts.
That said, CNC has more muscle when it comes to surface finish. It allows for smoother finishes than 3D printing, which makes it better for parts that require exceptional smoothness. It’s a far more agile fighter, too, as it can remove material faster than the rate at which 3D printing deposits it. This is less reliant on size and more on the amount of material needing removal. So, in cases where a lot of material needs removing, 3D printing might be more advantageous. Even then, size is still a constraint with 3D printing. Small parts are quicker to manufacture as setting up CNC machines can take longer than manufacturing itself, but using a CNC machine for larger components is more logical.
CNC machining is also a hands-down winner for greater quantities. While 3D printing is cheaper, higher volumes of parts and components are often more cost-effective when CNC machines are used. However, this will differ depending on several factors, including material costs, machine repairs and changes.
The verdict
So, who wins this time? Blue or red? CNC machining or 3D printing?
Well, sometimes, in boxing and manufacturing alike, there’s no clear winner. There isn’t a knockout punch or a final blow, but one of the fighters wins on points.
When it comes to 3D printing vs CNC machining, both have their strengths and weaknesses. 3D printing is highly unlikely ever to replace CNC machining, but there is a suggestion that the two opponents could, one day, work as a team.
With 3D printing’s design flexibility and CNC machining’s accuracy and precision, aerospace and automotive components can be crafted to the correct tolerances, even as low as ±0.005mm. 3D printed parts can be cut to size with a CNC milling machine, ensuring quick processes, smooth surfaces, and accurate dimensions. This also provides more cost-effective high-volume production, especially compared to injection moulding, and maintains consistency across batches.
There are even machines that have already strived to combine two in one. The ZMorph 2.0 SX, for example, is described as a multi-tool for 3D printing, CNC milling and laser engraving. Another option is the Snapmaker Artisan, a three-in-one machine that unites 3D printing, laser engraving and CNC milling capabilities.
Which contestant you want to crown the champion depends entirely on your organisation’s needs. Looking for agility, flexibility, and practicality? 3D printing is your best bet. If you want an experienced heavy hitter that delivers high volume and pure quality, then super-efficient CNC machining here at Sheldon Precision is a clear winner.
3D printer vs CNC machine? We think they need to be in different weight divisions.
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