How / parts needed to control 24v spindle w/ skr 1.3

Software / Firmware SKR Boards
1

Hey my fellow DIYers,

Main Question-
When using an SKR 1.3 running Marlin 2.0 what is needed to run a 24v spindle motor?

I’m assuming I would connect the spindle motor and the 24 volt power supply to a mosfet “control board” which would receive a pwm signal from the SKR 1.3 board… CORRECT?

Whole Story if interested-
I have a Prusa i3 Style clone 3D printer, and I’m about to convert it to be a “cnc/mill/engraver” for materials such as thin acrylic sheets, Milling pcbs etc…

At first I was thinking about just connecting the spindle motor to a pwm controller and power supply and just manually setting the speed of the spindle motor…

But then I remember that I have a brand new SKR 1.3 board, 5 stepper drivers, and a bigtreetech 3.5tft. Which I had to bond to upgrade the printer a while back before I bought my new 3D printer. It’s all brand new so I figured might as well use it after I had learned there are a few open source projects for Marlin 2.0 to run DIY CNC’s…

Or would I just be better off not changing the mainboard on the 3D printer and just attach the spindle motor and control the speed separately / manually through a pwm motor controller and using is a separate power supply just for the spindle motor?

Again I’m not trying to make something really elaborate and fancy to do complex work. I just want to engrave some plexiglass sheets and Mill some custom pcbs

Thanks

2

You can use pwm output from Marlin. It won’t do closed loop, so you will either need to be satisfied with open loop control or something else needs to be closing the loop.

The output depends on the controller. Skr can output 5V PWM on a random pin. Or it can toggle the fan pin, for example. The fan pin (+) is the voltage of whatever the input power to the skr is. The (-) side is either the source voltage or ground.

You can edit the spindle pins to pick which one you want and then M3/M5 will control it.

3

Thanks for the reply.

Yeah I understand I can get a 5v PWM signal from the SKR 1.3 board. I was just curious if the SKR board had a mosfet on any of the outputs that could provide the PWM signal at 24v ~10a… for example, the output on the SKR that controls the heat bed etc…

Instead of using an external mosfet being driven by the 5v PWM from the SKR board…

As for the open/closed loop, for now an open loop is all I need.

4

The fan has a mosfet on the low side (low side drive). It will be 12 or 24V depending on your input voltage.