Centroid Community CNC Support Forum

ShawnM wrote: ↑Sat Jan 14, 2023 9:51 am The feed rate override + button is there to increase the feed rate after you decrease it. Like Gary stated this is machining 101, if you understand feeds and speeds for your machine, bits and materials you never need to touch the feed rate override button. If you post a job and your machine can’t handle the book feeds and speeds numbers for what you are cutting you decrease the feed rate to find what works. Losing steps means you don’t have the machine setup or configured for optimal performance. If you overdrive a stepper, open or closed loop, it’ll miss steps. If your machine is not designed, setup or configured properly and you try to run it at 150% guess what happens?

Please share the model number of your motors and power supply(s) so we can see the specs of the motor and how much power you are feeding them. Your drives can handle 50 volts and supply 4.2 amps according to the Chinese manuals. I’m betting that’s PEAK power and not continuous.

I looked at your videos and in the video of the fault that machine is clearly being over driven.

... When the + button is only for increasing feedrate after you decrease it, why will it go over 100% feedrate when cnc12 not designed is for that?

The only thing is that feedrate override didn't work. And this has nothing to do with the stepmotor voltage and amps.

With no acceleration every machine will fail, because the torc force is to high.

Nigelo wrote: ↑Sat Jan 14, 2023 3:28 pm

... When the + button is only for increasing feedrate after you decrease it, why will it go over 100% feedrate when cnc12 not designed is for that?

The max feedrate AND the max override are set within the Wizard by you. If you did not apply a feedrate margin and left it just under the stall speed, of course the override will stall the motors when going over 100%. Keith has previously stated he calibrates each machine by increasing feedrate until each motor starts to stall, and then backs off feedrate by about 20% to arrive at the maximum. I also use this technique by back off about 30%. This calibration is the only time I ever need to go over 100%

The only thing is that feedrate override didn't work. And this has nothing to do with the stepmotor voltage and amps.

I think you mean that the override did not work with YOUR SETTINGS and yes, it has everything to do with the stepper motor capabilities i.e. voltage and amps.

With no acceleration every machine will fail, because the torc force is to high.

If you consider your problem to be inadequate acceleration whilst insisting on using current feedrates and 200% override then your configuration is incorrect. Go back to the wizard and reset the acceleration time for each axis - Double the current value would seem appropriate as a starting point.

You posted because you want help but don't seem to want to listen to Keith, Gary or Shawn - That's your biggest mistake

hope this helps

helicop wrote: ↑Sun Jan 15, 2023 10:08 am
2) The max machine feedrate, which I am decrease from 3000 to 1500 mm/m is exceeded by CNC12. You can see this on the end of the video. The speedrate was 1800mm/m, when the machine max is 1500mm/m.

ShawnM wrote: ↑Sun Jan 15, 2023 10:54 am

helicop wrote: ↑Sun Jan 15, 2023 10:08 am
2) The max machine feedrate, which I am decrease from 3000 to 1500 mm/m is exceeded by CNC12. You can see this on the end of the video. The speedrate was 1800mm/m, when the machine max is 1500mm/m.

This is not a new discovery, what you set in the wizard is the max feedrate for each axis. What you see on the screen when the machine is running is the combined feedrate. So on some moves where two axis are moving at the same time you will see a higher number than your max rate. This is the “combined feedrate” of both axis moving at the same time but neither axis exceeded the max feedrate set in the wizard.

Do you get the “bumping” when the feedrate override is set to 100%?