Design Guidelines: CNC Milling
Our basic guidelines for CNC milling include important design considerations to help improve part manufacturability, enhance cosmetic appearance, and reduce overall production time.
Maximum Dimensions (3-axis milling)
|10 in. x 7 in. x 3.75 in.|
|10 in. x 14 in. x 1.75 in.*|
|22 in. x 14 in. x 0.75 in.*|
|22 in. x 14 in. x 1.25 in.**|
|254mm x 177.8mm x 95.25mm|
|254mm x 356mm x 44mm*|
|559mm x 356mm x 19mm*|
|559mm x 356mm x 32mm**|
Maximum Dimensions (5-axis milling)
|2.6 in. x 2.9 in. x 3.9 in.|
|66mm x 73mm x 99mm|
|SIZE||0.25 in. x 0.25 in.|
|SIZE||6.35mm x 6.35mm|
Typically, Protolabs can hold a machining tolerance of +/- 0.005 in. (0.13mm). Part features are recommended to be thicker than 0.020 in. (0.51mm) in all regions and a nominal part thickness above 0.040 in. (1.02mm) is required. Maximum depth that can be milled is 2 in. (50.8mm) from either side of part. For specific milling dimensions by material, see maximum part extents for machining.
*These part sizes can only be milled from two sides, and in ABS, acetal, and aluminum 6061 and 7075.
**This part size can only be milled from two sides, and in Aluminum 6061.
5-Axis Milling Capabilities
We use 5-axis indexed milling—in addition 3-axis milling and turning—to machine parts. With 5-axis indexed milling (also referred to as 3+2 milling), two axes are stopped while the tool is engaged with the part. This allows for more complex geometries and non-orthogonal features like off-axis holes.
Better finishes are also possible on non-orthogonal surfaces and because 5-axis milling increases machining efficiencies, more cost-efficient parts can be had.
Typically, we break (debur) the edges on all machined parts. All machined plastic parts are left as-machined, which may leave visible tool marks. Some metal parts, on the other hand, allow more choice. Parts left with sharp edges should be handled with care.
|Edges broken with visible toolmarks|
||Edges broken with visible toolmarks, edges broken with light bead blast, or sharp edges with visible toolmarks|
|ALL OTHER METALS
||Edges broken with visible toolmarks or edges broken with light bead blast|
We currently support UNC and UNF threads from #2 up to 0.5 in., and metric threads from M2 to M12. Avoid modeling internal threads on your part design.
Sharp inside corners on a part will be radiused (rounded) as a natural result of the CNC machining process. Resulting radii will be identified on your quote.
Recommended text considerations for CNC milling:
- Recessed text should have a minimum stroke width of 0.020 in. (0.508mm).
- The spacing between characters on raised text should be 0.020 in. (0.508mm) or greater.
- For steel and titanium parts, recessed text should have a minimum stroke width of 0.037 in. (0.939mm), and spacing on raised text should be 0.037 in. (0.939mm) or greater.
- If design permits it, opt for raised text versus recessed.
Request More Information
Thanks! We’ve received your message and a member of our team will be in touch with you shortly.
You can find more information about Protolabs here:
Thanks for your interest in Protolabs. Please let us know how we can provide more information on our services. Once we receive your comments, an applications engineer from our team will follow-up as soon as possible.
If you have a 3D CAD model of your part ready, upload it online now to receive an interactive quote with free design for manufacturability feedback within hours.