What’s the difference between CNC machining and 3D printing?

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What’s the difference between CNC machining and 3D printing?

Precision Machining cnc machining

What’s the difference between CNC machining and 3D printing?

The most straightforward answer is: 3D printing is a material additive technology, and CNC machining is a material subtractive technology.

Differences in materials

The materials of 3D printing mainly include liquid resin (SLA) , nylon powder (SLS) , metal powder (SLM) , gypsum powder (full-color printing) , sandstone powder (full-color printing) , wire (DFM) , sheet material (LOM) and so on.

The materials of CNC machining are plates of ” stainless steel, plastic, brass, aluminum etc.” , through measuring the length, width, height of parts and wear, and then to cut the plate of the corresponding size for machining processing.


3D Printing material

Benefits of aluminum CNC machining

CNC Machining Material

There are more choices of CNC machining materials than 3D printing, all metal and plastic plates can be CNC machined, and the density of molded parts is better than 3D printing.

Differences of Part machining principles

As we mentioned earlier, 3D printing is an additive manufacturing process. Its principle is that the model is cut into N layers/N multi-points, and then stack them layer by layer/point-by-point in order, just like building blocks.
Therefore, 3D printing can effectively produce parts with complex structures, such as hollowed-out parts, while CNC is difficult to produce hollowed-out parts.
CNC machining is a subtractive manufacturing process, through various high-speed tools, cutting out the required parts according to the programmed tool path. Therefore, CNC machining can only process rounded corners with a certain radian, but cannot directly process inner right angles, it must be achieved by EDM.

Therefore, parts with internal right angles can be considered to make by 3D printing.

Refers to the surface, if the surface area of the part is relatively large curve, it is recommended to choose 3D printing. CNC machining curved surface is very time-consuming, and if the programming engineer and CNC operator has no enough experience, it is easy to leave obvious lines on the surface of parts.

It’s easy to understand the difference when some people say that 3D printing uses cake flour to form a cake, while CNC cuts a big cake into small cakes

Tips For Cnc Machining Parts Design 1024x576

CNC Machining

How Long Does 3D Printing take for plastic part

3D Printing

Differences in operating software

Most of the slicing software for 3D printing is easy to operate. Even a layman can be skilled in operating the slicing software within one or two days of professional guidance. Because the slicing software is currently optimized to be very simple, the support can be automatically generated, which is why 3D printing is so popular with individual users.

CNC programming software is much more complicated and needed professionals to operate it, Because there is many kinds of CNC machining programs to produce a component, the programming is very complicated. People with zero foundation generally need to learn at least half a year. The more commonly CNC programming software are UG, MASTERCAM, CIMATRON.

Difference in surface treatment

There are only some options for surface treatment of 3D printed parts, generally polishing, spraying, deburring, dyeing and so on.

There are many options for surface treatment of CNC machined parts , in addition to polishing, spraying, deburring, as well as electroplating, silk screen printing, pad printing, metal oxidation, laser engraving, sandblasting and so on.

There are various advantages and disadvantages for the CNC machining and 3D printing. Choosing the right processing technology is very important on your prototype project.


If you want to know more about the CNC machining, please search the 3Qmachining, there are more introductions about CNC machining.

Author: Mose Li

Author: Mose Li

Director of Project Engineering at 3Q Machining

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