I’ve upgraded my Shapeokos to run 1.5kw spindles. Got the VFD all wired up and it’s cutting beautifully.
The new spindle control within CM is also fantastic, I love having it spin up and down based on the job. So far though, regardless of the RPM’s I set for a toolpath, the voltage output is 0v or 5v - no gradient. Has anyone else run into this? It means I have to run everything at 24,000rpms (the spindle max), unless I want to switch back to manual control.
Side note, if you’re still on the fence about getting a water cooled spindle, at 24,000rpms I’m slotting through 6061 at 135in/min and .020 DOC all day long.
What Dan said, you need to set $30=24000 and then GRBL will generate a PWM that averages to a voltage proportional to the programmed RPM value.
Unrelated note: it’s also good practice to have a spindle warmup g-code file that you can run at the beginning of a session in the shop, that has the spindle ramping up from 0 to 24000 slowly over a few minutes, to get the spindle/bearing/grease up to nominal temperature. Not mandatory, but (probably) useful to optimize spindle life and accuracy and easy enough to do.
