Choosing the Right Finish for Your CNC Machined Parts
With the wide variety of surface finishes and treatments offered by Xometry, we've got your parts covered.
CNC Milling Services
CNC Milled prototypes and production parts in as fast as 1 day
High Quality Rapid CNC Milling
Xometry integrates seamlessly with over 2,500 qualified U.S.-manufacturing partners, including ITAR qualified CNC milling facilities. That massive network means that whatever your part, we have a shop and a machine that can make it. We support 3-axis, 4-axis, 5-axis milling, as well as right angle milling capabilities to rapidly create designs from simple straight lines to complex geometric shapes. Xometry gives you instant pricing, on-demand lead times, and DFM on materials and manufacturing processes for your custom CNC milled parts, no matter your industry.
Advantages of CNC Milling
Rapid Turnaround
Using the latest CNC machines, Xometry produces highly accurate, quick turn parts in as fast as 1 day.
Precision
Offers high-precision tolerances ranging from +/-0.001″ – 0.005″, depending on customer specs.
Custom Finishes
Select from a variety of finishes on solid metal and plastic parts, built to precise design specifications.
Scalability
CNC Machining is perfect for production of 1-10,000 parts.
Material Selection
Choose from over 50 metal and plastic materials. CNC Machining offers a wide variety of certified materials.
CNC Milling Materials
Available aluminum varieties:
- Aluminum 5052
- Aluminum 7075
- Aluminum 7075-T6
- Aluminum 6063-T5
- Aluminum 7050-T7451
- Aluminum MIC-6
- Aluminum 6061-T6
- Aluminum 2024-T3
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Available brass varieties:
- Brass C360
- Brass 260
- C932 M07 Bearing Bronze
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Available copper varieties:
- EPT Copper C110
- Copper 101
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Available plastic varieties:
- ABS
- Acetal [Delrin]
- Acrylic
- G-10 Garolite
- Nylon 6/6
- PEEK
- Polycarbonate
- PTFE [Teflon]
- Polypropylene
- Ultra-High Molecular Weight Polyethylene
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Available steel varieties:
- Alloy Steel 4130
- Alloy Steel 4140
- ASTM A36
- Stainless Steel 15-5
- Stainless Steel 17-4
- Stainless Steel 18-8
- Stainless Steel 303
- Stainless Steel 304
- Stainless Steel 316/316L
- Stainless Steel 416
- Stainless Steel 420
- Steel 1018
- Steel A36
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Available titanium varieties:
- Titanium Grade 2
- Titanium 6Al-4V
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CNC Milling Finishes
As-Milled
The finish option with the quickest turnaround. Parts are left with visible tool marks and potentially sharp edges and burrs, which can be removed upon request. Surface finish is comparable to 125 uin Ra finish.
Bead Blast
The part surface is left with a smooth, matte appearance.
Anodized (Type II or Type III)
Type II creates a corrosion-resistant finish. Parts can be anodized in different colors—clear, black, red, and gold are most common—and is usually associated with aluminum. Type III is thicker and creates a wear-resistant layer in addition to the corrosion resistance seen with Type II.
Powder Coat
This is a process where powdered paint is sprayed onto a part which is then baked in an oven. This creates a strong, wear- and corrosion-resistant layer that is more durable than standard painting methods. A wide variety of colors are available to create the desired aesthetic.
Custom
Don’t see the finish you need? Submit an RFQ and we’ll look into a finishing process for you.
Applications for CNC Milling
Rapid Tooling
Because CNC can be applied to virtually any material, it is perfect for rapid tooling, i.e., creating fixtures or molds.
Rapid Prototyping
The range of materials available, low cost per unit, and speed of production makes CNC a great option for prototyping.
End-Use Production
High-quality finish, vast material options and precise tolerances have made CNC a favorable technology for end-use parts.
Overview: What is CNC Milling?
The Basics of CNC Mills
CNC mills are automated cutting machines using a rotating spindle-head to cut away unwanted material. CNC milling machines come in a variety of sizes and different axis configurations. They are mainly utilized to cut harder metals but can work with workpiece materials ranging from plastic and aluminum to stainless steel and titanium.
How CNC Milling Works
CNC mills excel at profile cutting harder materials. Like all CNC machines, a CNC mill is controlled with G-Code created through CAM software. The Gg-Code instructs the machine where to move the tool head, how fast to spin the tool, how deep to cut, how to move the workpiece, and other factors relating to speed, feed rate, and coordination. The G-Code complexity depends on how many axes the milling machine has.
Mills can still be used for profile cutting of softer materials, but are not as cost-effective for that use as CNC routers. The main difference between these machines is that with a CNC router the workpiece remains stationary while the router cutting head is directed around the piece, while a CNC mill may move both tool head and workpiece. CNC mills are mainly used in industrial manufacturing, while CNC routing is more common for lower output manufacturing like woodworking.
Types of CNC Mills
3-Axis: The most widely used type of CNC milling machine. The full use of the X, Y, and Z directions makes a 3 Axis CNC mill useful for a wide variety of work.
4-Axis: This type of router allows the machine to rotate on a vertical axis, moving the workpiece to introduce more continuous machining.
5-Axis: These machines have three traditional axes as well as two additional rotary axes. A 5-axis CNC router is, therefore, able to machine 5 sides of a workpiece at in one machine without having to remove the workpiece and reset. The workpiece rotates, and the spindle head is able to also move around the piece. These are larger and more expensive.
Other Benefits of CNC Milling
CNC milling machines are built for precise manufacturing and repeatability which makes them perfect for rapid prototyping and low-to-high volume production runs. CNC mills can also work with a variety of materials from basic aluminum and plastics to more exotic ones like titanium — making them the ideal machine for almost any job.
Industries that use CNC Milling
CNC mills are the workhorses of the manufacturing world. Because of their tight tolerances and the variety of materials they are suited to, CNC milling is a crucial process in many industries. Some of the major industries that benefit from CNC mills are aerospace & defense, automotive, consumer products, energy, industrial machinery, medical, robotics, and R&D. CNC machines are also vital to many other manufacturing processes.
Aerospace and Defense
Automotive
Consumer Products
Electronics
Industrial
Medical and Dental
Robotics
Featured CNC Milling Resources
CNC Milling Design Guide
CNC machining is one of the fastest ways to build functional prototypes, product molds, low to high volume production runs, and fixtures.
Learn how to design your parts for CNC machining to ensure high quality and cost-effective results. Download your free guide today.
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CNC Machining Design Tip: Optimizing Internal Corner Radii
One of the ways to save on CNC machining costs is to leverage standard size tooling.
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