- Maximum part size (3-axis milling): 10 in. by 7 in. (254mm by 178mm)
- Maximum part size (5-axis milling): 2.6 in. by 2.9 in. by 3.9 in. (66mm by 73mm by 99mm)
- Minimum part size: 0.25 in. by 0.25 in. (6.4mm by 6.4mm)
- Maximum part depth: ranges from 0.75 in. to 3.75 in. (19mm to 95mm). The maximum depth that can milled from either side of the part is 2 in. (51mm). Please see our materials selection guide for more information.
Larger sizesWith 3-axis milling, larger part sizes may be available in ABS, acetal, aluminum 6061 and 7075, and magnesium materials.
Larger parts can be milled from top and bottom only—no side setups. Both standard and larger envelope sizes are nominal; parts that fit within these constraints occasionally cannot be manufactured due to fixturing or other considerations.
- For these materials with depths up to 1.75 in. (44mm), maximum size increases to 10 in. by 14 in. (254mm by 356mm).
- For these materials with depths up to 0.75 in. (19mm), maximum size increases to 22 in. by 14 in. (559mm by 356mm).
- For parts in aluminum 6061, depths up to 1.25 in. (32mm) are possible with a maximum part size of 22 in. by 14 in. (559mm by 356mm).
5-axis milling capabilityAlong with 3-axis milling, 5-axis indexed milling is used at Proto Labs. 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.
Our CNC machining process typically requires nominal part thickness to be larger than 0.040 in. (1mm). Parts may be as thin as 0.020 in. (0.5mm) in regions as long as the nominal part thickness stays above 0.040 in. (1mm). Features thinner than 0.020 in. (0.5mm) typically do not survive the machining process.
In general, tolerances of ±0.005 in. (0.13mm) are expected and achieved.
Sharp inside corners on a part will be radiused (rounded) as a natural result of the CNC milling process. Our automated quotes highlight areas where these radii will occur.
Text on parts
Recessed text should have a minimum stroke width of 0.020 in. (0.5mm). The spacing between characters on raised text should be 0.020 in. (0.5mm) or greater. If your design permits it, opt for raised text versus recessed.
All machined plastic parts are left as-milled, which typically means they show visible tool marks. Some metal parts, on the other hand, allow more choice. Magnesium, like plastic, is always left as-milled. Soft metals like brass, copper and aluminum can be lightly bead blasted leaving a fine matte finish. Hard metals like steel and stainless steel can also be de-burred with a light bead blast which removes metal slivers and sharp or particularly rough areas.
We provide the ability to easily add threaded holes to machined parts. We currently support UNC and UNF threads from #2 up to 1/2 in., and metric threads from M2 to M12. Because of the lack of standards between CAD packages for specifying threads, our automated systems decide where to put threads by looking for holes that could be pilot holes that are oriented suitably. Please avoid modeling internal threads on your part design. More details.
We offer a range of plastic and metal materials that can be CNC machined. Please note that only steel, aluminium, copper and brass are available for 5-axis machining at this time. See full list of materials.
- Stainless Steel
- Steel Alloy
- Steel Mild Low Carbon