We guarantee that our manufacturing partners follow ISO 2768 standards for all CNC machined parts. Parts machined with metal will follow ISO 2768-m (medium) or ISO 2768-f (fine). Parts machined with plastics will follow 2768-m (medium). Geometric tolerances down to ± 0004 in. (0.010 mm) are possible but must be clearly indicated in technical drawings. We can achieve tighter tolerances on shafts with up to H7 fits with manual quoting and on occasion tighter.

Read more about our standards for tolerances here

At Protolabs Network we offer CNC milling (​​3-axis, 3+2-axis and 5-axis) and turning. Milled parts can be machined up to 2000 x 1500 x 200 mm (78.7 x 59.0 x 7.8 in.) for 3/3+2 axis CNC milling. For 5-axis milling, the maximum part size is 650 x 650 x 300 mm (25.5 x 25.5 x 11.8 in.). The maximum diameter for CNC turning is 431mm (17 in.), length 990 mm (39 in). Minimum part dimensions recommended are around 0.39 x 0.39 x 0.39 in. (10 x 10 x 10mm).The minimum for feature dimensions is 0.5 mm. 

We are limited to a 1000 mm (39 in.) maximum size for parts on our platform. If you need higher dimensions, you can place the request through your account manager.

Deburring and edge breaking are standard procedures for all CNC machined parts. If there are any critical edges that should be left sharp, they must be clearly indicated in technical drawings. Surfaces will be free of defects such as scratches, dents, stains, blemishes, hanging marks, minor defects. Surfaces indicated as critical (primary (a) side, as indicated on the technical drawing) will be free of mill steps and other marks. For the secondary (b) side, minor hanging marks and up to 2 minor defects are acceptable. A number of post-processing and finishing methods can be applied to improve the surface roughness, visual properties and wear resistance of machined parts.

Read more about surface finishes for CNC machining.

We use machine learning algorithms to calculate the exact cost of any machinable part directly from a CAD file, based on millions of CNC machining orders we’ve previously processed. No more waiting for technicians to get back to you via email, we can generate an exact quote for you instantly (well, in about 5 seconds).

This means you always know the price up front. Simply upload a CAD file to generate a quote: get an instant CNC machining quote. Our quotes are completely free, you only need to create an account so we can protect your IP.

It’s so easy to use that we encourage mechanical engineers to use it constantly as they optimize their designs for cost. Whenever you’ve made a new design iteration, simply load both the old and the new design into our quoting tool and see if the price is different.

This technology means our manufacturing partners also don’t need to do their own machining quotes, which means less overhead for them. This makes the whole process less expensive, which translates into lower prices for our customers.

The main costs associated with CNC machining can be grouped into machining time, start-up costs, material costs, and feature costs. To reduce costs you need to understand the impact of these factors on cost.

The best way to reduce machining time is to design features that can be machined quickly, for example by choosing the correct radii for internal corners, reducing cavity depth, increasing wall thicknesses, limiting thread length and designing holes with standard sizes.

Material costs can be reduced by considering the size of the blank required, and the cost and machinability of the bulk material (softer alloys are faster to machine).

Start-up costs can be reduced by reducing the number part rotations or repositioning required to finish the part, for example by separating geometries into multiple parts that can be assembled later.

Feature costs can be reduced by only using tolerances when strictly necessary, removing all text & lettering, and avoiding multiple surface finishes.

These tips can be read in more detail in our full guide to reducing the cost of CNC machined parts.

We use algorithms to identify the best manufacturer in our network for your specific order, based on their proximity to you, their experience with similar parts and their available capacity right now. This allows us to balance our customers’ demands for speed, cost and quality better than ever before.

Read more about our network of manufacturers here

Protolabs Network was started by mechanical engineers and we have many more engineers and technicians in our team. Together we’ve written a lot of content on CNC machining over the years. You can find a selection of resources below, or you can head to our knowledge hub and filter on CNC machining to read case studies, in-depth design guidelines and explanations of different surface finishes.

We’ve also written a complete engineering guide to CNC machining. Here you can learn about how the many different kinds of mills and lathes work and the different materials available, so you can easily compare their benefits & limitations. You’ll also learn the basic design rules for machining and the most common applications of each material and surface finish, so you can make the right choices every time.

Customers in the US and EU can choose local or global manufacturing for CNC machined parts. Local orders are manufactured within your customs-clearance zones, allowing for shorter lead times (from 5 days) and faster delivery as there’s no need for shipments to clear customs. Global orders generally result in longer lead times at a lower price. The best option depends on the timeline and requirements of your project.

Using CAD (computer-aided design) modeling software and G-code, CNC milling and CNC turning machines remove material from a solid workpiece with precision and speed. CNC machines manufacture parts with tight tolerances and a range of impressive mechanical and chemical properties. Our custom CNC machining service is ideal for one-off jobs and low-to-medium volume production, thanks to automation and high repeatability.

Our global network of CNC machining centers manufacture custom parts for applications ranging from rapid prototyping to serial production. To start sourcing CNC-machined parts, simply upload a CAD file and technical drawing to our online Quote Builder. You’ll either receive an instant CNC quote and be able to start production in only a few clicks, or you’ll be directed to one of our engineers for design for manufacturability (DFM) guidance.

We offer 75+ metals and plastics for CNC machining, including aluminium, stainless steel, carbon and alloy steels, copper alloys, and engineering plastics. Our range has recently expanded with 24 new materials, including:

Phosphor bronze (CuSn5, CuSn6, CuSn8, CuSn12)

Inconel 625

Aluminium alloys (e.g. 5251, 5754, 2007)

Tool steels and high-performance alloys

This expanded portfolio gives you more flexibility when selecting the right material for your application.

Common CNC materials include:

Aluminium (lightweight, corrosion-resistant and versatile)

Steels (carbon, alloy, stainless: for strength and durability)

Copper alloys (including bronze, for wear resistance and conductivity)

Engineering plastics (e.g. PEEK for high-performance applications)

With our expanded offering, you have access to an even broader selection of industry-standard materials in one place.

Yes. We offer a range of high-performance materials, including:

Inconel 625 for high-temperature and corrosion-resistant applications

PEEK (including glass-filled PEEK) for demanding mechanical environments

Advanced tool steels and alloy steels

These materials are ideal for industries such as aerospace, automotive and industrial equipment.

Yes, bronze is now available as part of our expanded CNC material range.

We offer phosphor bronze alloys (CuSn5, CuSn6, CuSn8, CuSn12), which are ideal for components requiring:

High wear resistance

Low friction

Strong corrosion resistance

Typical applications include bearings, bushings and electrical components.

Material selection depends on factors including:

Mechanical properties (strength, hardness and wear resistance)

Environmental conditions (temperature and corrosion)

Weight and cost requirements

Our platform provides instant quoting and DFM feedback, and our team can offer guidance regarding the best material for your application.