Hi @jedi,
What VFD do you have ? You mentioned the Huanyang spindle, but the VFD is not necessarily the same brand and it’s important to know the model to provide accurate answers as to which parameter to adjust.
If you have a Huanyang VFD, I made a list of all the parameters I used in this thread
You will see that in my case I did set things to 400Hz where applicable (e.g. PD072), which specific parameter are your referring to ?
Double-check whether your spindle is actually a 400Hz model, it should be etched on the body or written in the description where you bought it. It is very probably the case.
About your last question: whatever CAD tool you are using, they all generate the “M3” commands that will automatically set the spindle speed during the job, nothing special to do.
The only (optional) modification I did in the G-code generation process was adding a small delay after the M3 commands, such that the spindle has time to accelerate to the selected RPM before moving to cut anything. I did that by adding the “G4 P5.0” line below in Vectric’s post processor file:
+---------------------------------------------------
+ Commands output at the start of the file
+---------------------------------------------------
begin HEADER
"G17"
"G21"
"G90"
"G0[ZH]"
"M0"
"G0[XH][YH][S]M3"
"G4 P5.0"