CNC spindle speed after new firmware update

I don’t have the means to find out, so I may be speculating.

After updating to the latest firmware, the spindle speed seems to be lower than the setting when machining with CNC.
The spindle speed setting is 8000 rpm, but it seems to be lower than that.

The machining speed is overloaded and machining runaway occurs.
I was suspicious because the machining results changed under the same conditions and with the same material.
S =8000 V=80 F=600 2 flutes 0.04 per flute
Under these conditions, I had to set the machining speed output to 60% to get the load, so I wondered if the RPM was really being generated.

Translated with (free version)


We do not change any settings regarding to the CNC spindle speed.

You can M1006 to check the current power.

Code description:


void GcodeSuite::M1006() {

SERIAL_ECHO("Tool Head: ");

switch (ModuleBase::toolhead()) {






SERIAL_ECHO("Current Status: ");


SERIAL_ECHOLNPAIR("Current Power: ", laser.power());

SERIAL_ECHOLNPAIR("Focus Height: ", laser.focus());




SERIAL_ECHOLNPAIR("Current Power: ", cnc.power());

SERIAL_ECHOLNPAIR("RPM: ", cnc.rpm());








I’m having the same situation mentioned by @Blockmodule after fw upgrade.

Spindle behaviour is different than before: even at maximum speed (as stated in the lcd) sound is different and you can see the revolutions of the collet. To avoid possible effects caused by post processor I tryied to set the speed by the main controller.

Machining of the same material with the same tool in equal condition is giving lower quality results.

I did a video too but it’s not explanatory.


We will look into this issue.

Did you mean Firmware V1.12.1? I will arrange some tests regarding this issue this afternoon. Could you please send me a video of the issue?

Best regards

Hi Edwin

I have found that the M1006 displays power and rpm.

I had rewritten the G-Code of the .CNC file output by Fusion360 and processed it with M3 P70.
The results on the M3 P70 are as follows and seem to be fine.

Tool Head: CNC
Current Power: 70
others < RPM: 8000

However, it seems that the motor may have become unstable because the machining conditions were calculated by S/V/F machining load calculation and different RPMs were used.
It might be better to use the P100 because of the variation in RPM.

If you think that lowering the rotation speed will reduce the torque and affect the variation in processing, the result will be unstable processing.

This is a bit disappointing because I wanted to control the rotation speed of blades such as V-bits, which melt due to friction if the rotation speed is too high when processing acrylic.

When I purchase the next linear module or 3D printer module, I will also purchase the CNC module.