If you’re just getting started with CNC routers, it’s perfectly normal to be unsure about the stepper motor size to use. What are the options available and when are they most useful?
CNC router stepper motors typically come in NEMA sizes 11-57. NEMA 23 is the most popular stepper motor size for hobbyist CNC machines. Stepper motor sizes smaller than NEMA 17 are used in animatronic and robotic applications, while larger ones are mostly used in larger CNC machines.
In this article, you’ll learn more about how stepper motors work, the various sizes, and tips on choosing one. We’ll also look at a few top-rated stepper motor options in the market today.
What Is a Stepper Motor?
A stepper motor is a DC motor device designed to turn electrical pulses into mechanical movement. It comes with a spindle or shaft, which rotates in discrete increments – usually 200 steps per revolution – when the right amount of electricity is applied to it.
A stepper motor is useful in scenarios where controlling movement is important. They are generally used in situations that require you to control synchronism, position, speed, and angle of rotation. This is why they are used in different personal and industrial setups, including plotter, printers, pick-place devices, engraving machines, X-Y tables, and more.
The Stepper Motor Technology Explained
Stepper motors rotate in distinct steps. They come with many coils that have been partitioned into what is known as phases. Once each phase is energized, the motor will move progressively from one step to another.
When a computer controls the movement, you can get highly accurate speed control as well as positioning. This is why the stepper-motor technology is commonly used in many applications where precise motion control is important.
Therefore, stepper motors are used in CNC routers because of the precisely repeated steps and the very consistent operating speeds.
CNC Router Stepper Motor Sizes
Stepper motors typically come in different pack size groups referred to as the NEMA sizing. The typical options in the market are NEMA 11, 14, 17, 23, 34, 42, and 57. This NEMA designation only defines the mounting interface of the motor. Other features, such as spindle length and motor length, may differ from manufacturers or even between models.
The sizing looks at the types of stepper motors with the same bolt pattern for typical mounting. A larger number means a larger overall motor frame size. So, a NEMA 23 one will have a frame size of 2.3 in (57 mm), while a NEMA 11 stepper motor, you’ll get a frame size of 1.1 in (28 mm).
It’s important to pay attention to the NEMA rating instead of body length. This is because body length for a NEMA 17 motor, for example, will vary from one manufacturer to the other. However, the achievable torque on the larger looking motor will always be higher. Below is a look at some of the most common NEMA options for CNC applications.
This option is mostly seen in larger equipment like 3D printers with a heavier workload and in smaller CNC machines where torque is important to make sure there is enough force for the tooling to pierce through the material being worked on. It also ensures that the machine can be easily moved.
These are generally the stepper motors chosen for industrial CNC setups that have cast iron or steel gantries, as well as bulky moving parts. They are the options typically chosen for systems where linear motion control is a requirement.
This is generally used in 3D printers and in the cheaper solid state desktop engravers. There’s a very low demand for torque in both the machine’s design in such applications, and there’s also no need for force to push past materials.
How to Select a Stepper Motor
There are a few questions you have to answer in choosing stepper motors for any purpose. They include the following:
- What level of accuracy do you need when positioning the load?
- How much torque do you need to move the load?
- How fast does the load have to move or accelerate?
- How will the motor be coupled to the load?
By answering these questions, you can choose the right stepper motor for the job you need to do. For a typical CNC router, however, a NEMA 17-23 stepper motor size will almost always do the job.
Top Stepper Motors to Buy for CNC Routers
Try this small package from Amazon if you want to see some stepper motors work. The entire kit can be purchased (at the time of publication) for around $45 USD:
|5 Pack of Small Stepper motors and associated driver boards.|
|ELEGOO UNO R3 Board to control the motor drivers|
|Multicolored Dupont Wire|
When you are comfortable using stepper motors and are ready to move on to a bigger project, we’ve put together a variety of stepper motors for your CNC. They are listed below:
This stepper motor is highly rated because it features Position Tracking Technology, which ensures you won’t have to worry about synchronization issues when working with it. The manufacturers have also included a position encoder to create a closed-loop structure that allows for automatic position correction.
Additionally, the encoder feedback algorithm and filtering technique give you accurate and noise-free operations.
Thanks to its commendable finish and construction, this is one of the best stepper motors you can find. It can be used in a wide range of applications, including on a CNC router and 3D printers. For the price, it is an excellent value for the money. You’ll find it very capable for CNC applications like Prusa, Rostock, and RoBo 3D. It’s also a good option for hobbyists.
This is another quality product from a brand respected in the stepper motor niche. The StepperOnline NEMA 17 motor can drive all kinds of 3D printers and CNC machines. Even when you are driving this at one ampere and 36 volts, it won’t heat up too much.
It can work for long hours without any hitch. It delivers enough torque, so it won’t slip while functioning. The durability and strength it offers means that some people end up choosing it instead of buying a NEMA 23 stepper motor.
This is one of the best NEMA 17 CNC stepper motors you’ll find in the market today. It works effectively on both 12V and 9V DC power. Running on 9V is recommended, though, but it’s nice to know you have the option of 12V if the situation calls for it. The construction is sturdy and durable, which means you can count on it for a long time. It’s another excellent option for hobbyists.
As you’ve probably deduced from the name, the most prominent benefit of this CNC stepper motor is its ability to run on low current, even though it has high torque. It can work well with any stepper driver that can handle medium current. Any hobbyist can work with the stepper motor as the instructions for usage are very clear. However, the size of the motor means you have to be sure you’ve got space for it.
This is another NEMA 23 stepper motor that can work for CNC machines, as well as 3D and Laser printers. It’s preferred for its quiet operation, but it still packs a lot of power. Its durable motor and high torque means you can get your job done quickly and with precision. With its impressive durability, you can use it for hours without a glitch. It’s excellent value for money.
CNC router motor sizes start from NEMA 11 and can go as high as NEMA 57. However, hobbyists and small businesses almost never need more than NEMA 23 stepper motors for the typical projects they need to work on.
If you’re unsure of what stepper motor size to go with, however, you should discuss extensively with the seller to get some recommendations based on the type of work you normally do with your CNC router.
- Electrical Engineering Portal: How To Pick The Right Stepper Motor For The Job And What You Need To Know
- AdaFruit: Types of Steppers
- Motion Control Products: Selection Guide for Stepper Motors
- Medium: The ultimate guide to buy the perfect stepper motor
- The Edge Cutter: Best Stepper Motors for CNC
- CNC 3D: CNC Stepper Motors – A machine builders guide
- Applied Motion Products: What Do NEMA Sizes Mean?