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CNC milling service

Source custom parts from our network of specialized CNC milling manufacturers. Source custom CNC milling parts using more than 50 different metals and plastics, available in more than 15 surface finishes. Tolerances down to ±.0008"

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What is CNC milling?

CNC milling uses rotational cutting tools to remove material from a workpiece to produce finished parts and products. This manufacturing process works well for many materials, including metals, polymers, wood and glass. CNC milling systems generally have 3 linear degrees of freedom: the X, Y and Z axis. This allows for top-notch precision and detailing. Protolabs Network also offers more advanced, 5-degree systems, where the tool head and machining bed (A and B axis) can also rotate. 5-axis CNC machines can produce parts with high geometric complexity without needing multiple machine setups.

Learn more about CNC milling and turning

Maximum part size for 3- and 3+2-axis CNC milling

There are several types of CNC milling machines, each with its own distinct maximum part size. 3-axis and 3+2 axis machines have the lowest start-up costs and can produce parts with relatively simple geometries.

3-axis milling

Size Metric units Imperial units
Max. part size for soft metals [1] & plastics 2000 x 1500 x 200 mm 1500 x 800 x 500 mm 78.7 x 59.0 x 7.8 in 59.0 x 31.4 x 27.5 in
Max. part for hard metals [2] 1200 x 800 x 500 mm 47.2 x 31.4 x 19.6 in
Min. feature size Ø 0.50 mm Ø 0.019 in
[1] : Aluminum, copper & brass [2] : Stainless steel, tool steel, alloy steel & mild steel

3+2 axis milling

Size Metric units Imperial units
Max. part size for soft metals [1] & plastics 2000 x 1500 x 200 mm 78.7 x 59.0 x 7.8 in
Max. part for hard metals [2] 1200 x 800 x 500 mm 47.2 x 31.4 x 19.6 in
Min. feature size Ø 0.50 mm Ø 0.019 in
[1] Aluminum, copper & brass [2] Stainless steel, tool steel, alloy steel & mild steel

Maximum part size for 5-axis CNC milling

The more advanced of the milling machine family, 5-axis centers can produce parts with more complex geometries. These machines require fewer machine setups so they are more productive.

Size Metric units Imperial units
Max. part size for all materials 2000 x 1500 x 200 mm 78.7 x 59.0 x 7.8 in
Min. feature size Ø 0.50 mm Ø 0.019 in

Available materials for CNC milling

Example of CNC milling metals
Metals

A wide range of metals for CNC machining, with applications in multiple industries. Ideal for both one-off prototypes and end-use custom parts.

Example of CNC milling plastics
Plastics

A wide range of plastics for CNC machining, with applications in multiple industries. Ideal for both one-off prototypes and end-use custom parts.

CNC milling surface finishes

Improve your part’s performance by selecting high-quality surface finishes that enhance the roughness, hardness, chemical resistance and cosmetic features of your finished component.

Browse CNC milling surface finishes

CNC milling tolerances

We follow ISO 2768 standards for CNC machining.

Limits for nominal size Plastics (ISO 2768- m) Metals (ISO 2768- f)
0.5mm* to 3mm ±0.1mm ±0.05mm
Over 3mm to 6mm ±0.1mm ±0.05mm
Over 6mm to 30mm ±0.2mm ±0.1mm
Over 30mm to 120mm ±0.3mm ±0.15mm
Over 120mm to 400mm ±0.5mm ±0.2mm
Over 400mm to 1000mm ±0.8mm ±0.3mm
Over 1000mm to 2000mm ±1.2mm ±0.5mm
Over 2000mm to 4000mm ±2mm
*Please clearly indicate tolerances for nominal sizes below 0.5mm on your technical drawing.

CNC milling design guidelines

Check the recommended and technically feasible values for the most common features encountered in CNC machined parts.

Learn more in our engineering guide to CNC machining

Feature Recommended size Feasible size
Min. feature size Ø 2.5 mm Ø 0.50 mm
Internal edges R 8 mm R 0.25 mm
Minimum wall thickness 0.8 mm (for metals) 1.5 mm (for plastics) 0.5 mm (for metals) 1.0 mm (for plastics)
Holes Diameter: standard drill bit sizes
Depth: 4 x diameter
Diameter: Ø 0.5 Depth: 10 x diameter
Threads Size: M6 or larger Length: 3 x diameter Size: M2

Why should you choose CNC milling?

We have high standards for CNC milling

We manufacture your custom parts according to strict manufacturing standards and ensure all parts and processes adhere to The Protolabs Network Standard.

  • Every custom part gets checked on site by our manufacturing partners according to our guidelines.

  • Inspection reports and other types of quality documentation are available on request to assure the highest quality and compliance.

More resources for CNC milling

Learn more about how CNC milling works and how to design parts to get the most out this machining process.