What are the advantages and disadvantages of CNC machining?

While CNC machining is a viable and even ideal manufacturing process for many applications spanning prototyping to the medium-scale production of end-use parts, it’s not without its flaws. In this section, we cover the benefits and limitations of this subtractive machining process.

CNC machining offers excellent accuracy and repeatability. Both milling and turning can produce parts with very tight tolerances, which makes CNC ideal for high-end applications such as in the aerospace, aviation and automotive industries. Most materials used in CNC machining have excellent and fully-isotropic physical properties and are suitable for most engineering applications.

In general, CNC machining is the most cost-effective manufacturing process for producing low-to-medium numbers of metal parts. This means you can use CNC for single prototypes or to produce up to 1,000 units.

While these benefits make CNC machining an attractive option for engineers, the subtractive nature of the technology renders certain more complex geometries very costly or even impossible to manufacture.

Speaking from a financial perspective, the startup cost of CNC machining is much higher than it is for 3D printing. If you’re looking to produce low-cost prototypes from plastic, then 3D printing may be a better option where set-up is concerned.

Lead times for CNC machining tend to be longer than for 3D printing as well, as the average lead time for CNC is 10 days compared to the much lower 2-5 days for 3D printing. CNC machines are not as widely available as 3D printers, as they require more expert knowledge to operate effectively.