Spindle RPM vs Feedrate

I am new to CNC Milling. Reading through the help tips in EstlCam I saw something interesting. Feedrate too slow and it will cause heat and dust. To fix it slow the RPM or increase the feedrate. I see Ryan’s idea of the RPM speed controller for the Spindle. I will most likely copy that idea. ( I also like the progress on the PID speed comtrol.) But before I do I was wondering if you could accomplish similar results with the Feedrate % multiplier built into the Marlin Firmware. Keep the Spindle at full RPM and if you need to speed things up or slow them down use the LCD to adjust the Feedrate multiplier. That will make the machine execute all GCode movement commands slightly faster/slower. I do that on my 3D printers fairly often to improve quality at certain layers.

Will that work? What other issues might that cause?

The only issue I can foresee is with vertical verses horizontal movements. In some cases you may want to speed up the horizontal movements but not the vertical (or visa Versace) and this idea can’t accommodate that

Is there a rule of thumb for milling that could help a new user? Like if you see it starting to vibrate a lot and getting choppy would you want to speed up movements or slow down?

Where can I go to learn more about Milling? YouTube channel or videos? Books etc.?

Before you get into all of that you should very easily be able to get amazing cuts in wood of any kind. The range of “really good” settings in wood are huge. If you can’t get that right “by ear” a PID is really going to be difficult to grasp. I know it seems like the more you know the easier but there are some other good practices in over all CAM setup, and tool selection that matter so much more. A basic speed control does help so you can actively try faster and slower RPM but I highly suggest sticking with that for a while.


A bit of bed time reading
BUT I doubt the MPCNC could attain recommended feed rates.
As Ryan says listen, watch and feel the machine. (not the revolving bit of course)

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Those numbers seem mighty high. This one is actually pretty solid from my comparisons to what I actually use. The one you linked said 40mm/s The one below is saying 17mm/s, but also has all the numbers I care to enter without going super crazy.


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WOW! That’s a great tool! Definitely a great place to start as I consider new tools or materials.

FSWizard also exists as Android application https://play.google.com/store/apps/details?id=com.beta.fswizard_lite
I installed it recently. It looks very promicable.