CNC vs 3D Printer

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Updated January 16, 2023

Many tech enthusiasts are excited now that the best 3D printers are affordable enough for at-home use. However, some of the best printers are also available for industrial purposes. And when it comes to heavy use, many other types of machinery rival 3D printers. Below, we’ll compare CNC vs 3D printers. Then, we’ll explain how, although used for similar purposes, each has its strengths and weaknesses.

KEY TAKEAWAYS:

  • CNC machining uses a subtractive process by removing material from a block, whereas 3D printing uses an additive process of layering material into an object.
  • CNC machining works with a wide variety of materials and is superior in accuracy and speed compared to 3D printers.
  • 3D printers are helpful for small batch production and cost much less than CNC machines.

For more great info on 3D printers, we have plenty of articles explaining the various models, such as DLP vs LCD 3D printers. And we also have some buying guides listing things like the best 3-in-1 3D printers.

Insider Tip

Some 3D printing models can now build models made of various metals like aluminum and stainless steel.

Differences Between CNC Machining and 3D Printing

The quality of 3D printers has gotten to a point where they now compete with heavy equipment like CNC machines. However, although they can be used for rapid prototyping and produce industrial parts in bulk, there are some big differences between the two types.

The main difference comes in the process that goes into making an object.

CNC machines use a subtractive process, meaning they start with a block of raw material and then cut away with various tools like lathes, drills, or mills.

On the other hand, 3D printing is an additive process. It takes a material source and melts or cures it, adding it layer by layer. Eventually, these layers result in a 3D model.

If you complete this and want to build on your 3D printer knowledge, we have some technical spec comparisons, like the difference between a 32-bit vs 8-bit 3D printer. We also have guides comparing specific models, like the Zmorph VX vs Snapmaker.

Precision

The cutting tools used in CNC machining are exact, resulting in incredibly tight clearances and superb dimensional accuracy. For example, many CNC machines offer accuracies within .025mm.

On the other hand, many 3D printers are highly accurate but don’t get near the precision of CNC. A significant reason is that the 3D printing process relies on heating and cooling, which increases the chance of warping or shrinking.

Production Speed

The subtractive process used in CNC machining is quicker in production than the additive method of 3D printing. Therefore, a CNC is your best bet for those needing a fast-paced production tool.

Warning

If printer filament is kept in a climate with excessive moisture, it can begin absorbing the water, causing it to lose its strength.

Cost

The greatest advantage of 3D printers over CNC machines is the affordability of their upfront cost and maintenance. The materials used in 3D printers are cheap and don’t have incredibly complex parts that cost a lot to replace. On the other hand, CNC machines are made up of many tools, like drills and lathes. As a result, they are highly complex and can be costly to fix.

STAT: Plastic-based 3D print objects should not be used or kept in environments exceeding 150 degrees celsius for long periods. (source)

CNC vs 3D Printer FAQs

What types of materials do CNC machines work with?

CNCs work with a wide range of materials, from hard substances like steel and metal alloys to softer materials like wood and plastic.

What is rapid prototyping?

This term refers to using a computer-programmed device to manufacture 3D objects.

What is the downside to subtractive manufacturing?

Although fast and precise, the subtractive process is more costly and produces much more waste than additive methods.
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