How to choose a stepper motor for CNC Router?

How to choose a stepper motor for CNC Router?
There are a couple of factors that you need to consider when choosing a stepper motor for your work. Here is a brief overview of those factors that you need to check before making the purchase. These are also the factors that we have considered in choosing the ten best stepper motors for you.
CNC Stepper motor
Torque rating
Stepper motors get rated according to their holding torque in oz. /in (ounces/inch) or Newtons per centimeter or meter. For instance, a stepper motor with Nema 23 might have 175 oz. /in as torque. This means it has the ability to hold 175 ounces on one arm of one inch length attached to motor shafts, which refers to the holding torque. It is used in comparing motors. You should also note the amount of current the motor draws and the voltage needed by it to work.

Unipolar and bipolar
Stepper motors are unipolar or bipolar, which refers to the way the coils remain connected. Without getting into technical details, it suffices to say that bipolar motors are the ones used the most widely. These come with a high torque output because of the way the coils remain wired. Though switching the coils requires highly complex circuitry, that's not an issue as the driver modules are here to do that for you. Wiring the coils in a particular way can turn unipolar motors into bipolar ones. All stepper motors for hobbyists are bipolar.

Power supply
The power supply has to deliver the current and voltage for your selected controller and motors. Going for higher current will not hurt but the controller’s voltage and yours has to match. For instance, say you have 4 x NEMA 23, with 2.8 amps and 2 amps are needed by the controller. So, (4 x 2.8) + 2 amps is equal to 13.2 amps. If you multiply that by twenty-four volts to get Watts, you will have 316.8 W. They are either rated by Watts or Amps, so here you can use a 350 Watt 15 amp supply.

Types of machines
Selecting a stepper motor also depends a lot on the kind of machine you are going to build or have and the type of material you are about to cut. So, here is a brief outline on the approach you need to take for selecting motors for a router and foam cutter.

1. For the CNC routers:
A good idea is to get Nema 23 with 175 oz. /in and upwards, if you do not have a machine that is small like a CNC engraver. It is generally used to make PCB (Printed Circuit Boards), and the description mentions that it’s made for soft materials. However, you can get Nema 17 too, if the power and torque are good enough. Keep your budget and your needs in mind while choosing a stepper motor from our list, and it will be easy for you to select the right product.

2. For the CNC foam cutter:
Cutting foam using a hotwire foam cutting machine is called cutting by radiance, and it actually melts and not cuts the thing. So, the feed rate and temperature has to be correct for the load on the motors to amount to nothing. The weight of the moving machine parts gives the load, and you will have to keep that in mind while making the purchase.

Now that you know the options for the best stepper motor for cnc, you can go ahead and start to build your own CNC. As a hobbyist you are required to look for the different options required for a DIY CNC machine and we have worked and researched with multiple woodworkers and Bill Baum himself to figure out the best options available.

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