Tips on How to Choose Stepper Motors For CNC Routers

Tips on How to Choose Stepper Motors For CNC Routers

Generally, you are going to need at last NEMA23 from 175oz/in upwards unless your machine is very small such as a CNC engraver. These are quite often used for making Printed Circuit Boards(PCB) and if you check the description they will say only for soft materials.

So let’s look at a couple of examples.

For routers, the cutting material plays a big part in our decision. Harder materials will need a more powerful stepper because the cutting bit is being driven into the material.

The WorkBee from Ooznest in the UK which is based on the design. It uses NEMA23 of 175 oz/in. If you check some of the offerings online for 6040 CNC routers you’ll quite often see in the description 57 size motors, which is the metric equivalent of 2.3 inches or NEMA23’s and these usually come with 175-200oz-in motors

If you intended to cut very hard materials then high torque steppers motors will be required usually around 300-400 oz/in and you may need to go up to NEMA34 and you will need a strong frame to support that.

CNC controllers for the DIY machine
Now we know the stepper motors required for our project we can match them to a suitable CNC controller. The controller converts the g-code we’ve created and sends step pulses to the stepper motors. It also takes input signals from the machine such as limit switches and E-stops.

So there are 3 things we need to know:-

Number of Axes. So usually 3 for routers and 4 for a foam cutter
Current and voltage we need to supply to the stepper motors
How do we intend to connect the computer to the CNC controller
Number of Axes
CNC routers can use 3 or 4 axis controllers. There is only 3 planes of movement X, Y and Z but some designs use two stepper motors on one axis. My OX CNC router uses two NEMA 23 motors on the Y-Axis as its a gantry type router. Some move the table bed for the Y-Axis on sliders and only need 1 motor for the Y-Axis. Like a 3d printer bed