Skip to content 
In the CNC machining world, the two systems – CNC mills and CNC routers – are popular. Because of their subtractive-cutting nature, they are frequently mistaken for one another. However, they are distinct in their roles and capabilities. What a CNC mill can achieve may not be possible with a CNC router and vice versa.
So, are you confused too, and want to know the difference? Or do you recognize they are different but lack clarity on their specific use cases? If so, read through this article to grasp the differences in their structure, working, and applications.
What is a CNC Mill?
A CNC mill is a more compact machine, with an enclosed or semi-enclosed design. It is also computer-controlled, designed to shape and cut harder materials like steel, titanium, and aluminum with high precision.
In a CNC mill, the spindle, which holds the cutting tool, can move vertically or horizontally, while the workpiece remains fixed on a solid bed or vice. The spindle can rotate along the z-axis and can have multi-axis movements.
CNC mills are ideal for creating intricate parts, molds, and tools. They can perform drilling, boring, and tapping, with tight tolerances and excellent surface finishes. Due to their high-precision machining, they suit industries like aerospace, automotive, and medical device manufacturing.
What is a CNC Router?
A CNC router is a computer-controlled cutting machine used, primarily used in the woodworking space. However, it can also cut plastic, foam, and softer metals like aluminum. Unlike traditional routers, CNC router operates with high precision, guided by software that directs its movements along the X, Y, and Z axes.
The machine can be recognized from its gantry-style frame, ideally for cutting large sheets. The gantry is the moving horizontal beam that holds the spindle and travels across the material. The cutting bed is flat and stationary. Only the tool moves across the bed to cut and shape the material.Functionally, CNC routers excel at basic cutting, carvings, and engravings, largely used in applications like cabinet making, sign crafting, and decorative furniture production.
CNC Mills vs CNC Routers: How are They Different?
The brief may have helped you understand the key functionalities of each machine, now let’s debate about the difference in a bit more detailed manner.
| CNC Routers | CNC Mills | |
|---|---|---|
| Construction | Gantry-style frame, Open | Compact Closed or semi-closed structure |
| Tolerances | ±0.005 to ±0.010 inches (±0.127 to ±0.254 mm) | ±0.001 inches (±0.025 mm) |
| Compatible Material | Wood, plastic, foam, soft metals (e.g., aluminum) | Hard metals (steel, titanium), tough alloys |
| Material Shape | Sheet form | Block form |
| Control Software | Simpler interface for cutting and engraving operations | Advanced control software with more functionalities |
| Tools | Straight bits, V-bits, ball nose bits, compression bits | End mills, face mills, ball nose mills, drill bits |
| Spindle Speeds | 10,000 – 24,000 RPM | 1,000 – 10,000 RPM |
| Applications | Furniture, signage, musical instruments, simple prototypes | Aerospace parts, engine components, medical instruments, molds |
1. Working Principle and Construction
Both, CNC Mills and CNC routers work on the same principle – a tool moves across, removes the material, and shapes it in the required form. But, both achieve this operation through different machine configurations.
CNC routers are immediately identifiable with their gantry-style frame and relatively largely processing bed. This design supports the processing of large sheets of softer materials. Whereas, CNC Mills usually have a robust closed or semi-closed structure, where a block of material is fed rather than a long sheet.
In CNC routers, the tool moves across a stationary workpiece, supported by a moving gantry. This design offers faster cutting but is limited to 3 to 5 axes. In contrast, CNC mills have short movement spans but the mobility of the tools goes up to 12 axes. This enables it to shape more complex contours.
2. Accuracy and Precision
CNC routers can achieve a tolerance between 0.005 to ±0.010 inches (±0.127 to ±0.254 mm). That’s sufficient for the industries they are being used for, like woodworking.
In contrast, CNC mills use more advanced and precise tools, which enable them to achieve tight tolerances, around ±0.001 inches (±0.025 mm). This high precision is due to their rigid construction, slower cutting speeds, and shorter tools, which reduce vibrations.
3. Material Compatibility
We already hinted at the material capabilities of the two machines, and that’s also one of the biggest differences among them.
CNC routers are primarily used for shaping wood, plastics, foam, and certain soft metals like aluminum. Whereas, are built to work with hard materials like steel, titanium, and tough nickel alloys.
The material’s physical configuration also differs among the two. In CNC routers, a sheet of material is fed i.e. placed on the bed. It can be anywhere between 0.5 to 2 inches. Whereas, in CNC routers, a block of material is placed on the work table, and the tool moves around it, shaping it from all sides.
4. Design and Control Software
Since they are CNC-operable machines, the designs for both can be drawn on CAD and CAM software. However, the control software is slightly different for the two.
CNC routers, generally perform cutting and engraving operations, so their interface is designed to be simpler. In the case of mills, as the process requires high precision and multiple types of operations are supported, the software is advanced with more control capabilities at the user end. It may seem complex, but offers more control over the whole process.
5. Tooling Options
CNC routers and CNC mills, both use different tools as they handle different materials. Routers usually work with softer materials like wood or sheet metal. The machining processes are also basic i.e. cutting, engraving, or carving. So, their tool range is limited; some common ones are straight bits, V-bits, ball nose bits, and compression bits.
CNC mills have a wider range of tooling options, as they handle harder materials and have to perform multiple operations on a block. Their tools are rigid, and built for higher forces and temperatures. Some common tools include end mills for profiling, face mills for flat surfaces, ball nose mills for 3D contours, and drill bits for precise hole-making.
6. Machining Parameters
As the compatible materials and tools are different, so are their respective machining parameters. CNC routers operate at higher spindle speeds, often exceeding 10,000 RPM, with some models reaching up to 24,000 RPM. Feed rates are equally higher.
CNC mills run at lower spindle speeds, usually between 1,000 and 10,000 RPM. The feed rate is also lower, as the focus here is on precision.
7. Costs
The cost, to be exact, changes based on the size and machining capabilities. In general, CNC routers are cheaper than CNC mills. Entry-level CNC routers are also available for hobbyists under $1000. However, CNC mills are normally used on a commercial scale, and even entry-level cost thousands of dollars.
8. Applications
The applications of both CNC machines differ largely due to their precision and material handling capabilities.
CNC Routers are used in:
- Furniture components: legs, shelves, doors, and ornamental carvings.
- Signboards and logos
- Musical instruments, including bodies for guitars and violins
- Simple models and prototypes.
CNC mills are used in industries where metals are employed or where tight tolerances are a requirement:
- High-precision parts for aircraft and spacecraft
- Engine components, transmission parts
- Medical instruments and implants
- Mold and Die Making
How Richconn Can Help?
At Richconn, we offer CNC milling for over 60 metals with tolerances up to 0.002 mm. Our comprehensive fleet of CNC mills includes 3-axis, 4-axis, and 5-axis milling centers, which can produce complex geometries with the utmost precision. Place an order and get your parts delivered in just two days.
If your project parts require CNC milling processes, please contact us for a free quote for your project.
