3D printing vs CNC Machining – Key differences

3D printing vs CNC Machining – Key differences

Although both 3D printing and CNC machining are both great for lower quantity part production and creating prototypes dependant on component requirement, there are distinct differences between the two methods. We investigate the differences and benefits of both to hopefully help you decide which one is the best option for you.

Key Differences

The main difference between 3D Printing and CNC machining is that CNC machining is a subtractive process. This means that you put a block of material into a machine and the machine will cut your part from the blank. The advantages of this are that the machines have great dimensional accuracy and you can use almost any material including wood, metal and plastic. The obvious downfall of this is the waste that is created in the process.

3D printing means that the parts are being built layer by layer meaning that they can be incredibly intricate in design. Complex designs that would normally mean the manufacturer would have to create two, three or more smaller components can normally just create one part without the added process of combining smaller components.

Choice of Materials

CNC Mills

As previously mentioned, CNC machines can work on a large variety of materials including wood, metals and plastics. You will, of course, need to use different cutting tools depending on the material that you are using. But the tools are mostly standardized, so you don’t need to be too worried about ordering different parts for the machine.

3D Printers

3D printers are mostly restricted to different types of thermoplastics, powers or resins. Metals are becoming available but generally at a premium cost. However, as 3D printing is still a relatively recent technology, this is quickly improving. Thermoplastics can be mixed with other materials such as ceramics, wood, metal, but the workpieces produced on a 3D printer will not be as robust as workpieces cut from a block of metal. As thermoplastics and resin 3D printers use completely different methods, a resin printer cannot handle thermoplastics – and vice versa. HP’s Multi Jet Fusion technology uses a completely new method of manufacturing by spreading a fine layer of powder across the bed and then sprays a fusing agent onto the powder. This fusing agent is a heat conductive liquid which absorbs heat energy causing the areas which have been sprayed to fuse together. This process produces parts with high accuracy and impressive strength. As technologies improve with 3D printing the strength of some of these plastics is becoming increasingly impressive.

Ease of Use

For the ease of use, 3D printing is the winner, hands-down. A CNC machine needs an experienced operator that knows what they’re doing and even then, it is quite a labour-intensive process. This is why, if you are ordering parts from a company, a small quantity order will normally be far more expensive when ordering from a company that will use a CNC machine.

In contrast, a 3D printer operator will simply pick the part orientation, fill, machine parameters then set the machine going and only light observation is required until the print is complete.


The cost is a slightly more complex issue, for orders in the low double figures 3D printing is generally cheaper. However, for higher double figures and certainly when you get into the 100s of parts needed, alternate methods such as CNC may be your best bet. Again, if you are wanting to use an external company; the easiest way to figure this out would be to approach a CNC company and a 3D printing company with what you need and get a quote from both.

Why AAM Ltd?

AdvancedAdditiveManufacturing is dedicated to offering the best in industry 3D Printing technologies. The latest addition to our growing capabilities is the HP Multi Jet Fusion technology. We will soon be offering the full range of materials currently available for the system: PA11, PA12 and PA12 GB. For more information on the technology please visit: https://www8.hp.com/uk/en/printers/3d-printers.html. To get a quote please upload a 3D file to our order page or simply leave us a message on our contact form and we aim to be in touch within 1 working day.


To conclude, the answer to “Which method is best for me?” is, of course: It depends – sorry for the anti-climax. But hopefully, it may have given you a better idea of which method could be better for you. If you definitely need your parts to be in metal or if you need 200 of them; CNC may currently a better solution than 3D printing. If you want a strong, plastic prototypes or final use products which you need quickly or custom manufacturing then 3D printing is the best option.

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