CNC Milling is "off"

So, I attempted to cut the word TESTING into a piece of 20x20x.5 wood and for some reason, the CNC mill will randomly plunge deeper than it’s supposed to, will miss letters, and write letters over other letter. Any ideas on what I need to check?


It could be your z axis missing steps. What is your plunge speed? Maybe z driver voltage?

Also make sure your rigid coupler is not slipping.

I apparently suck with a multimeter and can’t get the stupid multimeter to get a reading from the DRV8825 chips. I bought two multimeters from Harbor Freight - a clamp type and the cheapo one, and I have no idea wtf I am doing at this point. I watched the Pololu tuning video but my multimeter looks a LOT different.

You didn’t really give any information to go off of.

Are you using my kit? If not exactly what are you using?

Are you sure it is a hardware problem not a software problem.

What is your plunge speed, How did you make your gcode?

If you want to check the stepper driver (is it a drv8825?) turn the meter to the lowest DC setting it has. Then negative of the mutlimeter to the negative on the green plug. Positive goes to the little silver round potentiometer on the driver.


I ordered most of the parts from your amazon links.
DRV8825 stepper motors/Ramps 1.4/Arduino - 12v power cable
NEMA 17 motors

for gcode generation I am using aspire to create the text and using quick engrave for the toolpath creation.
Then this is fed to Repetier.

I use a Mac so I had to change the baudrate in the code to 115200 to be able to send it commands.


Your on your own for the stepper settings then, find a data sheet and keep an eye on the temps.

I would bet your issue is with Aspire and the z axis speed and accel settings.


Those setting have nothing to do with your machine when it is running gcode. The speeds will all come from aspire. Maybe you should try estlcam first since I made a walk-through, then when you see how all the speeds are you can try and translate it into aspire.

We are good. I set all all the steppers to .8 and everything looks better.

Thanks for all the help and the awesome CNC design!