Differences Between CNC Router vs Mills
CNC routers and CNC milling machines converge at many points. They have almost similar advantages, user challenges, and room for creativity. It is indeed easy for the inexperienced user to confuse the two machines. However, the accustomed user of the CNC router and mill can tell the differences at a glance.
For instance, there is a striking difference between the two CNC machines regarding how their axes interact. For the router, the spindle moves along the three major axes (X, Y, and Z) while the workpiece is stationary. In the CNC milling machines, including the versatile vertical milling machine, the workpiece is restricted to the Z-axis while the workpiece moves in the X and Y direction.
Other than this difference, there are many other areas we can compare the two important machines. That is the essence of this article. However, before we deep dive into this comparison of CNC mill vs CNC router, it would be prudent to have an overview of each of them.
What Is A CNC Router?
A CNC router is a type of machine that creates shapes through material removal in different materials. It relies on computer-controlled technology and machine tools to form shapes in wood, metal, and other types of materials. The router carries a tool that cuts into the material according to a predetermined design.
CNC itself is an acronym for Computerized Numerical Control. It is a type of technology used in manufacturing industries and elsewhere, which uses software to control the direction and depth of the cutting tool. As the cutting tool rotates at a predetermined cutting speed, it is also moving in a planned direction.
When the machine in question is a router, the process is termed CNC routing, and the machine is a CNC router. The most popular applications of this process are engraving, curving, and cutting materials. Note that there is also a manual CNC router. The CNC router is less prone to human error, adding convenience and efficiency to the tasks.
How Does CNC Router Works ?
The CNC router comprises several important accessories or parts, from the motor to the CNC controller. It is important to identify these parts first before looking at how the CNC router works. These parts include:
Motor
frame
spindle
table
CNC controller
axis drive
slides
The Motor
The CNC router comes with a motor, which drives the spindle. There are two main types of motors in this case: Servo motor and stepper motor.
For enhanced accuracy and machining speed, choose a CNC machine with a servo motor. However, this motor tends to be more expensive than the stepper motor. If the CNC router has a speed of more than 2,000 RPM, it most probably has a servo motor. The repeatability of the servo motor is also excellent. CNC routers with this motor are typically more accurate.
The stepper motor is common in CNC machines that are more affordable and smaller. The accuracy and speed requirements for CNC routers with stepper motors are relatively lower. These motors work better at speeds lower than 2,000 RPM.
Motor efficiency affects the overall efficiency of the CNC machines. A significant amount of the power that a stepper motor consumes turns into heat. This type of motor has an efficiency of up to 70%. Compare that to a servo motor, whose efficiency can reach 90% depending on the load. Therefore, you can use the motor aspect to decide which CNC router to invest in.
The Frame
This is the backbone of the CNC router. It supports the entire machine structure. For this reason, the frame must be strong. A lot of forces are generated during the machining processes and the components also contribute to the weight.
The stability and strength of the frame determine the accuracy of cuts. To avoid cut inaccuracies and such problems, ensure that this component of the CNC router is of the highest quality.
The spindle
Another crucial component of this CNC machine is the spindle. Like in any other CNC machine, the spindle in the router rotates the cutting tool. The core duty of the CNC router spindle is to regulate the machine tool speed.
Holding the spindle above the machining bed and along the axis is the gantry. The gantry has two degrees of movement. It can travel front and back on the Y-axis and right and left on the X-axis.
The table
You will notice that there are several types of tables for the CNC router. The most popular are vacuum table, T-slot & vacuum table, and aluminum T-slot table. All these tables have their pros and cons, which can help in choosing the ideal one.
The aluminum profile table comes with T-slots that accommodate screws for securing the workpiece. It is effective at ensuring that the work remains steady during the process. This type of table is prominent in the industries that regularly work with acrylic and PVC. Users like the corrosion resistance, durability, and low-maintenance nature of the aluminum T-slot table for the CNC router.
There is also the full CNC vacuum table. It features a vacuum pump and several adsorption holes. The vacuum pump creates negative pressure for flawless loading and unloading.
For the T-slot and vacuum table, the setup incorporates a vacuum CNC table and a clamp. It employs vacuum adsorption. This type of table works perfectly for irregularly shaped workpieces. However, it can still work with workpieces of regular shapes.
The CNC controller
To execute the G code for operation on the workpiece, the CNC router has a CNC controller. This controller turns the G-code into signals that dictate the movement of the motor. As an interface, the CNC controller allows the user to input instructions and follow the CNC routing process.
With its control of the motors, the CNC controller is responsible for several outputs. These include the cooling system, machine tool changers, and cutter speed. Indeed, the CNC controller is a sort of computer. It comprises a power supply, processor, and memory.
The Drive System
This feature plays the irreplaceable role of driving the machine axes. The components that make up the drive system are the motor and lead screw. These components work together to create the different linear motions of the CNC router.
The CNC router can have either a rack & pinion setup or a ball screw instead of the lead screw. The three are options for the drive system. The prices for the three differ, with the ball screw drive system being the most pricey. As you would expect, it has the most accurate and efficient performance.
A more affordable drive system is the rack & pinion, which mostly suits longer axes. If you need slightly more accurate results, the lead screw drive system is a good choice.
The Slides
As the name suggests, the slides or ways of the CNC router are the guides for the smooth movement of various components on specified axes. The slides work in tandem with the high-quality frame to deliver high-precision cutting.
Most manufacturers make the slides from special stainless steel rods. These rods are special in the sense that they have undergone precision cutting or grinding. At least two of these rods support an axis, with wider separation between the pair of rods meaning more accuracy.
The working principle of the CNC router is not much different from that of the conventional handheld router. It cuts various materials in different shapes. However, a big difference is that the CNC machine is more robust and suitable for a wider range of materials. The accuracy of the CNC machine is also much higher. The CNC version uses a computer program to guide the tool path.
Now, to operate the CNC router, one has to plug in or start several items first. These are:
Dust collector
CNC controller panel
Remote controller
Vacuum table
Next, you need to choose the cutting tool or end mill. Typically, there are several options considering there are different flutes and shapes. Alongside the flutes, there is also another aspect of the bit that you need to consider – the shapes. End mills for CNC routers can be V-bit, ball-nose, or flat. Remember to consult with the shop manager before using any particular cutting tool on the router.
Sometimes, the cutting tool that you need to use is already in the CNC machine. In that case, you only need to confirm it is tight enough and well-aligned.
After setting up the cutting tool, shift attention to the workpiece. Secure the workpiece on the table, then set up the axes – X and Y.
After these steps, you are now set to load the CAD/CAM software file. There should be a slot on the CNC controller box where you can insert the flash drive bearing the file.
Why Choose CNC Milling Machines?
Like the CNC router, CNC milling machines have their place in the industry.
Versatile Milling
Compared to the manual mills, CNC milling machines are highly versatile. The milling machine can machine almost any material, from various types of metal to plastics. Provided the material is available in a block, the CNC machines have no problem with material removal. Furthermore, the automated milling machine can be adjusted to perform other operations. These include acting as a drilling machine and even cutting.
Fast Operation of CNC Milling Machines
Compared to conventional milling machines, CNC milling machines are reliably fast. Conventional manual mills require human intervention most of the time. This costs a lot of time and is prone to many human errors.
As for CNC mills, the setup can carry several tools at once. The spindle of the milling machine exchanges these tools automatically to make the machining process fast. Where a conventional mill would take weeks to complete a job, a CNC mill takes a few hours.
Precise Machining
This is another prominent reason to choose CNC milling cutter machines. The adherence to the specifications of a part is a big benefit of these advanced machining marvels. That’s expected because this milling machine machine depends on instructions from a computer program.
Using a computer removes errors that emanate from human judgment. As a result, parts from CNC milling cutters can reach tolerances of 0.004mm.
CNC Router Vs Mills: What are the Differences?
When you are looking for a CNC machine, you cannot escape from the question of which type to pick. A choice between CNC mills vs CNC routers is common for most users. Fortunately, there are key differences between the vertical milling machine and CNC router. Here is our breakdown of these differences:
Materials
There is a marked difference between CNC routers vs. mills regarding the type of material that the machines can cut. That’s mainly because of the different spindle capabilities of these CNC machines. Specifically, the spindle speed for the CNC router and CNC milling machines is different.
The CNC router features a higher spindle speed in comparison to the CNC router. The spindle speed of the CNC router can go beyond 20,000 rpm. While others can be slower, it is rarely slow enough to cut hard materials.
Consequently, the CNC router works best on softer materials – plastic, wood, aluminum, and so on. With the right router bits, CNC routers can make excellent cuts on wood.
CNC milling machines have slower spindle speeds. The speeds of the milling machine rarely go beyond 6000 rpm. At such speed limits, the mills can cut harder materials such as titanium and steel. You could also use the CNC milling machines on harder materials, albeit with a slow feed rate.
In short, this point shows that the rotational speed of a CNC machine can determine the type of material that the machine can remove or cut.
Machining Speed
When comparing the machining speed for these CNC milling machine and router machines, it is also important to note that they normally cut different materials. As we have said above, CNC routers thrive with softer materials while CNC routers are more heavily built, hence suitable for harder materials.
That said, CNC mills feature powerful motors that can generate fast speeds while cutting tougher materials. The milling machine can reach speeds of around 1000 RPM. However, this is not anywhere close to the top speed of a router, which can be near 20,000 RPM.
Modern CNC routers have good motors that help achieve such speeds. Moreover, the frames of these machines are light compared to those of the milling machine. The acceleration of the ball screws and drives is therefore swifter. So, when the router is machining soft materials, it can reach its highest speed.
Machining Accuracy
The rigidity and general design of the CNC milling machines result in high precision and accuracy compared to the CNC router. Having cast iron construction adds to the accuracy of machining processes. CNC routers typically have aluminum construction, which affects machining accuracy.
Generally, the design of the machine is deliberate according to the machining accuracy requirements. Harder materials need higher precision and tighter tolerances, particularly in the manufacturing industry for precision parts. For wood and related materials, the level of precision is not as high.
Tooling Options
The difference in the tooling options emanates from both the materials the machines can cut and the configurations of the machines. For the CNC router, the main workpieces are flat. The router does not have to have a large clearance between the tool and the workpiece. The spindle of the router is in an X-Y-Z setup.
On the other hand, CNC milling machines have milling tools that cut much thicker workpieces. Therefore, the allowance between the tool and the workpiece has to be larger. The nature of the tool must also suit the harder materials that the mill normally tackles. The spindle for the CNC mill overlooks the workpiece in an X-Y setup during the milling operation.
From these configurations and based on the material to cut, the tooling options for the milling machine and CNC router differ.
Applications
There is also a marked difference in the industries that use items from CNC milling vs CNC routing. For its accuracy, speed, and capability to machine a variety of materials, the CNC milling technology is applicable in a wide range of industries.
Aerospace Industry
One popular destination for CNC milling parts is the aerospace industry. Composite, plastic, and metal parts for this industry are usually products of CNC milling machines. Engineers can produce these parts quickly and accurately using horizontal milling machines and vertical milling machines.
Automotive Industry
The automotive industry is equally fond of parts from CNC milling machines. Like the other industries, they can use both vertical milling machines and horizontal milling machines. The choice of whether to use a vertical mill or a horizontal mill depends on the detail and size of the cut. Vertical milling machines are excellent at machining details on the workpiece. Horizontal milling machines are ideal for heavy milling tasks.
Again, the versatility of the machines is a big asset here. Whether it is plastic or metal parts, the manufacturers can rely on CNC milling.
Medical Industry
Even in the medical manufacturing industry, modern milling machines are very popular. This industry uses many intricate parts that can only come from an equally accurate machine. Using the tight tolerance capability, CNC mills help produce prosthetics, surgical tools, implants, and other items.
Signage and Woodworking
Being different in design and capability, CNC routers come in handy in different industries. The most popular industries for the technology include signage and woodworking. Mostly applicable to softer materials, these tools help in carving, engraving, and other forms of 3-D works. Woodworkers are particularly at home with the CNC router.
Cost of Milling Machine and CNC Router
As there are many brands of both CNC milling machines and CNC routers, there are bound to be wide price disparities. Every product costs depending on the power, size, features, and other aspects. However, in most cases, CNC mills are going to cost more than CNC routers for a particular capability level.
That is not to say there are no pricey CNC routing machines in the market. As is the general truth everywhere, the best machines in either category are usually the most pricey. That said, the best CNC router can be markedly costlier than the worst CNC mill.
Why is it so? The reason is that with a couple of hundred dollars, you can get a decent CNC router. That may not be enough money for even the lowest-grade CNC milling cutters. Often, the price of a CNC milling machine is in the range of $1,000 and above. Some cost even well over $100,000!
Conclusion
After looking at the similarities and differences between CNC milling machines and routers, it is clear that both of them are useful. Each has a specific application, so it might seem simple to determine which one to buy. However, it adds even more value to invest in machines for milling operations and CNC routers.
The CNC milling operation can complement the rigidity challenges of the router, while the router brings higher spindle speed, which can be useful in some jobs.
It is true that milling cutters and CNC routers paired with the right CNC machine tools can do small complex jobs and larger jobs. However, the router suits the more lightweight work compared to the CNC mill’s robust pieces.
The point is that it is always better to invest in alternative manufacturing processes if you are constantly involved in a variety of machining operations.
For more on these CNC machines plus other machining operations, read more from our blog or contact us.
Author
Gavin Leo is a technical writer at Aria with 8 years of experience in Engineering, He proficient in machining characteristics and surface finish process of various materials. and participated in the development of more than 100complex injection molding and CNC machining projects. He is passionate about sharing his knowledge and experience.