CNC machining is a common subtractive manufacturing technique. Unlike 3D printing, CNC typically starts with a solid piece of material and then uses various sharp rotating tools or knives to remove the material to achieve the desired final shape.
CNC is one of the most popular manufacturing methods, offering excellent repeatability, high precision, and a wide range of material and surface finishes, from proofing to high-volume production.
Additive manufacturing 3D printing builds parts by adding layers of material, no special tools or fixtures are required, so initial costs are kept to a minimum
When choosing between CNC and 3D proofing, there are some simple guidelines that can be applied to the decision-making process. In this article, we'll cover key considerations for both technologies to help you choose the right one.
As a rule of thumb, all parts that can be manufactured by subtraction should generally be CNC machined. 3D printing generally only makes sense if:
When subtractive manufacturing cannot produce parts, such as highly complex topology-optimized geometries.
When the delivery time is very short, the 3D printed parts can be delivered within 24 hours.
When low cost is required, 3D printing is usually cheaper than CNC for small batches.
When a small number of identical parts are required (less than 10).
When the material is not very easy to process, such as metal superalloy or flexible TPU.
CNC machining provides parts with higher dimensional accuracy and better mechanical properties, but this usually comes with higher costs, especially if the number of parts is low.
If higher part counts (hundreds or more) are required, neither CNC machining nor 3D printing are cost-competitive options. Traditional molding techniques, such as investment casting or injection molding, are often the most economical options due to economies of scale.