Ideal for prototypes and low volume production parts (1 to 40+).
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ISO 9001:2015 | JOSCAR
CNC Machining Processes
Looking for a reliable, quick-turn supplier of machined plastic and metal components? With hundreds of CNC machines, our unmatched in-house capacity ensures your parts are shipped on-time, every single time. At Protolabs, our CNC machining facilities are designed for both rapid prototyping and low-volume production of end-use components.
CNC milling is a subtractive manufacturing process that uses 3-axis milling and 5-axis indexed milling processes to rapidly cut solid plastic and metal blocks into final parts.
CNC turning with live tooling combines both lathe and mill capabilities to machine parts with cylindrical features from metal rod stock.
CNC Machining Materials
Design Guidelines for CNC Machining
|Maximum Part Size||
3 axis: 254mm x 178mm x 95mm
5 axis: 66mm x 73mm x 99mm
(Max size for Aluminium 559mm x 356mm x 95mm)
650mm x 650mm x 300mm
|Minimum Part Size||6.35mmx 6.35mm||0.50mm|
|Tolerances||Typically, Protolabs can maintain a machining tolerance of +/- 0.1 mm. Parts may be as thin as 0.5 mm in regions as long as nominal part thickness is above 1 mm. Maximum depth that can be milled is 50 mm from either side of part. For specific milling dimensions by material, see maximum part extents for machining.||+/-0.020mm|
|Radii||Sharp inside corners on a part will be radiused (rounded) as a natural result of the CNC machining process.
Resulting radii will be identified before the part is milled.
|A radii of 2 mm will be applied to sharp internal corners as standard.|
|Text||• Recessed text should have a minimum stroke width of 0.5mm.
• The spacing between characters on raised text should be 0.5mm or greater.
• Minimum recessed text depth of 0.3mm.
• If design permits it, opt for recessed text versus raised.
|Plastic and soft metals: Minimum width of 0.457mm, depth of 0.3mm. Example text size would be 16 point Arial Rounded MT font.
Hard metals: Minimum width of 0.838mm and depth of 0.3mm. Example text size would be 22 point Arial Rounded MT font.
|Upload a Part||Upload a Part|
|Factory Capabilities||Network Capabilities|
|Tolerances||+/- 0.1mm||+/- 0.020mm|
|Upload a Part||Upload a Part|
Tolerances guaranteed through our digital network
Through our digital network of manufacturers powered by HUBS, we guarantee that our partners follow ISO 2768 standards for all CNC machined parts. For metal parts you have the choice of ISO 2768-m (medium) or ISO 2768-f (fine). Parts machined from plastics will follow 2768-m (medium). Geometric tolerances down to ±0.010 mm are possible but must be clearly indicated in technical drawings. Our network can achieve tighter tolerances on shafts and holes, with up to H7 fits (ISO 286-2), and on occasion even tighter tolerances via manual quoting.
All network partners follow ISO 2768 standards for CNC machining. It is possible to select medium or fine for metals. Further accuracy can be requested using 2D drawing tolerances.
Our factory will either follow ISO 2768 standards for CNC machining or provide a general tolerance of ±0.1 mm. There are no selectable options, so 2D drawings are not required.
|Factory only||Network metals only||Network plastics or metals|
|Internal corner radii||Detailed on 3D quote||R2 mm as standard*||R2 mm as standard*|
|Tolerance method nominal dimension#||General Tolerance||ISO 2768-f fine||ISO 2768-m medium|
|0.5mm** to 3mm||±0.1 mm||±0.05 mm||±0.1 mm|
|Over 3mm to 6mm||±0.1 mm||±0.05 mm||±0.1 mm|
|Over 6mm to 30mm||±0.1 mm||±0.10 mm||±0.2 mm|
|Over 30mm to 120mm||±0.1 mm||±0.15 mm||±0.3 mm|
|Over 120mm to 400mm||±0.1 mm||±0.20 mm||±0.5 mm|
|Over 400mm to 1000mm||±0.1 mm||±0.30 mm||±0.8 mm|
|Over 1000mm to 2000mm||Not applicable||±0.50 mm||±1.2 mm|
|Over 2000mm to 4000mm||Not applicable||Not applicable||±2.0 mm|
# ISO 2768 is feature based: the tolerance band will apply to each and every feature on your part and is not related to overall part size.
*A radii of 2 mm will be applied to sharp internal corners as standard, more options can be requested.
** Please clearly indicate tolerances for nominal sizes below 0.5mm on your technical drawing
Tolerances guaranteed by Protolabs
Typically, Protolabs will maintain a general machining tolerance of ±0.1 mm or better.
The tolerance will be clearly stated on your quote, at this stage it is not possible to select tigher tolerances for factory options made in a few days, but our partner network can produce to tighter tolerances.
Parts may be as thin as 0.5 mm in regions as long as nominal part thickness is above 1 mm. Maximum tool depth that can be milled is 50 mm from any side of the part. For specific milling dimensions by material, see maximum part extents for machining.
Surface finish: Typically, Protolabs offer a surface finish of < 1.6 µm Ra (Roughness average) across the range of CNC materials. Ra 6.3 µm to Ra 0.8 µm are typical for general CNC machining. Optional bead blasting will result in a slightly rougher, but uniform, matt finish. See the surface finish guide for detailed images.
All components are inspected and measured, using calipers, micrometres, pin and thread gauges. Dimensional Inspection Reports (DIRs), using high accuracy Coordinate Measurement Machines (CMM’s) are also available on request.
ISO are the International Organisation for Standardisation and issue global standards to harmonise manufacturing. ISO 2768 defines three tolerances classes, fine, medium and course. Each class has a tolerance band proportional to the nominal dimension being measured. The main benefit of using a general tolerance, like ISO 2768-f, is that components can be produced directly from 3D CAD without the need for a 2D drawing. It also greatly simplifies producing a 2D drawing, as every dimension already has a tolerance applied, fewer tolerances need to be added to define critical dimensions.
Why Choose Protolabs for CNC Machining?
Advantages of CNC Machining
The subtractive process of CNC machining provides multiple benefits for both prototyping and low-volume production parts.
- Precision and repeatability
- Tight tolerances
- Production-grade materials
- Quick-turn parts within 1 day
CNC Machining Applications
CNC machining is widely used throughout the aerospace, medical, automotive industries for its ability to rapidly manufacture precise parts in production-grade materials. Typical CNC parts, include:
- Housings and enclosures
- Fixtures for manufacturing
- Gears and bearings
- Internal mechanical components
- Medical instrumentation
What's in an Online CNC Quote?
How much does CNC machining cost?
Costs vary based on complexity, quantity and lead time. The best way to find out is to submit a 3D CAD model and get an interactive quote with design for manufacturability (DFM) feedback. Because we use proprietary software and automated fixturing processes, there are no up front non-recurring engineering (NRE) costs. This makes purchasing quantities as low as 1 to 200 parts cost effective. Prices compared to 3D printing are comparable to somewhat higher, but machining offers improved material properties and surfaces.
What types of threading options are available?
We offer UNF, UNC, and metric threads for machining along with coil and key inserts (but do not supply or install the inserts). These are available on both milled or turned CNC parts. View this page to see our complete threading options.
What is the maximum part size for CNC macining?
Maximum part size will vary based on your selected material. Our largest part size offered is 559mm x 356mm x 95.25mm and is available in Aluminiums. View this table to see maximum dimensions by material.
Where can I learn more about CNC design?
We have a variety of resources on CNC machining and how to design parts for the process. Here are some of our favorites:
What are the advantages of CNC machining?
Product designers and engineers choose CNC machining to rapidly produce prototypes and production parts. The manufacturing technology offers a high level of precision, engineering-grade materials, quick-turn lead times.
What is the digital network at Hubs?
Our global network of premium manufacturing partners powered by Hubs offers expanded capabilities, tighter tolerances, volume pricing, and the ability to handle more complex parts. You can visit hubs.com and click on the ‘Capabilities’ tab in the navigation bar at the top of the page for the full list of capabilities available through Hubs.
"We primarily use Protolabs to test new ideas...as we consider a potential design improvement, we want the ability to create parts and see how they perform as quickly as possible.”