Rapid Prototyping Service

CNC vs. 3D Printing: What’s the Best Way for Prototypes?

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Henry

15 years of experience in prototyping and manufacturing.

CNC (Computer Numerical Control) and 3D printing are two of the leading manufacturing technologies for Creating Rapid prototypes but use completely different production techniques. In this blog, we compare the two methods in different aspect so that you can make a choice before you start your project.

WHAT IS CNC PROTOTYPE MACHINING?

CNC Prototyping machining is a subtractive process, it creates the final part by removing material from the initial workpiece with a CNC machine. Computer Numerical Control (CNC) technology controls the motion of the cutting tool and workpiece to create the desired part.

CNC subtractive Machining

WHAT IS 3D PRINTING PROTOTYPING?

3D printing prototyping is an additive manufacturing process that add materials layer by layer to form the desired product. This process requires no special tooling or fixtures. With laser energy or heated extruder, material layers are solidified to form the prototype.

CNC PROTOTYPING VS 3D PROTOTYPING

Materials

CNC prototyping material is available from plastics to metal. Material you can use with CNC prototype machining include plastic prototype materials like ABS, Nylon (PA66), Polycarbonate (PC), Acrylic (PMMA), Polypropylene (PP), POM and PEEK and metal materials include aluminum alloys, steel, stainless steel, titanium and brass.

3D printing materials mainly include liquid resin (SLA), nylon powder (SLS), metal powder (SLM), plastic Filament (DFM), etc.

So, if your prototype needs better material properties closed to production materials, CNC machining will be better for your prototype project.

Geometric Complexity

CNC machining is subtractive manufacturing, through various high-speed cutting tools, cutting out the required parts according to the programmed cutting path. This means CNC machining can only process rounded corners with a certain radius, but cannot directly process inner right angles due to radius of the cutting tools.

3D printing is an additive manufacturing. it can effectively process and produce parts with complex structures, such as hollow parts, while CNC is difficult to process hollow parts. Therefore, 3D printing is a better choice when the parts have complex Geometry and a sharp corner requirement.

Accuracy And Sizes

CNC machining offers tight tolerance and excellent repeatability. Different 3D printing methods offer different dimensional accuracy. below is table to show some of properties of CNC machining and each type of 3D printing method. you will find that if you need a high accuracy prototype, CNC machining will be your choice.

TechnologyToleranceMinimum wall thicknessMaximum part size
CNC machining± 0.01 – 0.125 mm0.75 mmMilling: 2000 x 800 x 1000 mm Lathe: Ø500 mm
SLA± 0.2 mm0.7 – 1.0 mm300 x 300 x 300 mm
SLS± 0.3 mm0.7 – 1.0 mm300 x 300 x 300 mm
FDMDesktop: ± 0.500 mmIndustrial: ± 0.200 mm0.8 – 1.0 mmDesktop: 200 x 200 x 200 mmIndustrial: 900 x 600 x 900 mm
SLM/DMLS± 0.100 mm0.40 mm230 x 150 x 150 mm

Surface Quality

3D printed plastic part (left) and CNC machined plastic part (right)

In terms of surface quality, CNC is better than 3D printing. CNC can produce workpieces with a high surface quality with cutting tools. In opposite, the layer-by-layer printing process of 3D printers leaves a rough surface texture on the workpiece.

Cost

the cost of CNC machined prototypes is generally higher than 3D printed prototypes. this Because CNC machines are more expensive than 3D printers and CNC machining use more time to build a prototype.

Speed

CNC machined prototypes are usually need around 3 days while 3D printed prototypes need less than one day. So, 3D printing can make rapid prototypes than CNC machining.

IN SUMMARY

To compare CNC prototyping with 3D printing prototyping, we use a table to compare each factor they have as below:

FactorCNC Prototyping3D Prototyping
Working processSubstract manufacturing, cut workpiece to final partsAdditive manufacturing, builds parts layer by layer
Materialsworks with metals, wood, plastics, and alloysLimited to thermoplastic materials
Possible GeometryLimited internal complexitySupports complex internal and external geometries
WastageHigher material wastageLow material wastage, used as needed
Manufacturing TimeSlower than 3D printing, takes hours to create a single piece.Faster, creates parts in minutes
Prototyping CostRelatively expensive due to machine and accessories costs.More cost-effective due to low machine cost
Part ToleranceHigh tolerance level of ±0.01 mm.Slightly lower tolerance of ±0.1 mm
Part strengthCNC parts tend to be strongerweaker than CNC prototyping

If you need high précised prototypes, CNC machining is the best choice. if you need a prototype fast and low cost, 3D printing is better for you. KUSLA is a leading prototype manufacturer in China, we can provide CNC machining service and 3D printing service which can help you get your prototypes done quickly.

Regardless, if you’re unsure about which method to use for your prototype, feel free to contact Kusla at any time, and we will provide you with a professional and prompt suggestion.

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Get in touch with our professional team today, and we will respond to you within 24 hours.

Employees of Kusla.

Gang Liu

Marketing Director

Employees of Kusla.

Hua Liu

Project Manager

Employees of Kusla.

Yiyang Zhao

Project Manager

Employees of Kusla.

Lu Wang

Technical Sales

Employees of Kusla.

Anming Li

Technical Sales

Employees of Kusla.

Xiaoli Wu

Technical Sales

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Request A Quote

Get in touch with our professional team today, and we will respond to you within 24 hours.

Employees of Kusla.

Gang Liu

Marketing Director

Employees of Kusla.

Hua Liu

Project Manager

Employees of Kusla.

Yiyang Zhao

Project Manager

Employees of Kusla.

Lu Wang

Technical Sales

Employees of Kusla.

Anming Li

Technical Sales

Employees of Kusla.

Xiaoli Wu

Technical Sales

Please enable JavaScript in your browser to complete this form.
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