Are my steppers undersized? System just freezes on some cuts.

[wado1971]

I need some help. I'm hoping the answer is not simply that my steppers are undersized.

The issue I have is that Mach4 simply stops moving the axis during a cut. No error - simply stops motion on all axis and leaves Mach4 in a responsive state but unable to jog. I've had this issue for a long time but up until now, as my machine was not build complete, I had plenty of potential issues to investigate. But now with build complete I'm trying to run some performance tests to determine how far I can push the machine and I'm simply unsure if I've reached a performance limit or I still have a system problems which must be solved. I'll explain some of the key symptoms and specs.

Specs: DIY Fixed Gantry Steel Router, 2.7 HP spindle, Nema23 Schneider steppers 225ozin with controller built in, Mach4 (v2.2914), EthernetSmoothStepper (v186), THK Linear rails.

Symptoms/Etc.

• Mid cut the steppers simply stop moving. Can’t hear anything resembling chatter or missing steps. Mach4 then simply stops moving ALL the axis – I can still disable, enable, hit the jog buttons, and even change settings – all looks ok but will not jog. No error in Mach4.
• Only closing Mach4 and reopening will allow me to jog again. I don’t need to reboot the ESS. It does however not remember axis position and I must re-home.
• Has happened both in jog mode and with code running. All types of cuts – HSM, reaming (z-axis only), profile passes (x-axis only). Always the machine has no signs of ‘stress’ and inspecting the cut location on stopping I’ve never seen any indication of an issue – no chatter marks, aluminum welding, etc – surface finish at instant of stopping looks perfect.
• The issue only occurs when I’m pushing the machine a bit. I’ve always assumed an issue with the steppers but don’t know how to pinpoint.
• I’ve completely removed the limit switches in Mach4 configuration thinking it was crosstalk – no change.
• I’ve isolated all electrical power for computer, controller, etc into individual breakers thinking it was too much draw on input (at one point had an air compressor on same outlet as stepper power supply!).
• Using FSWizard software on one of the cuts that creates the issue outputs a cutting force of 27 lb. I have then used a force scale attached to the axis and measured maximum I can pull the axis prior to stepper skipping with an output of 55# - Not sure if this is an appropriate relationship. I could simply be stalling the motor during cut. BUT when I stall it by physically stopping it I can hear the motor missing step and Mach4 remains perfectly responsive to jogging while the issue described now makes Mach4 jogging unresponsive. ??

Any help, suggestions, or similar experiences are greatly appreciated. I have a build thread (here) on this machine but figured a separate post with the “Need Help!” prefix would be better.
Thanks,
Wado

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[ger21]

Mid cut the steppers simply stop moving. Can’t hear anything resembling chatter or missing steps. Mach4 then simply stops moving ALL the axis – I can still disable, enable, hit the jog buttons, and even change settings – all looks ok but will not jog. No error in Mach4.

Definitely sounds like a Mach4/SS issue.
If the motors stall, they'll make a loud "Grinding" type noise.

The issue only occurs when I’m pushing the machine a bit.

Neither Mach4 nor the Smoothstepper will know if your steppers stall, or are heavily loaded, so this is most likely just a coincidence.

[wado1971]

Thanks for the input Ger.
I did some more testing and I don't think it's just coincidence although I've been asking myself the same question, "how does the ESS or Mach4 know anything from the motor". I do need to supply a separate 5v signal from the ESS to the motor pin "optocoupler" (something about NPN sinking) in order for the motor to initialize but I don't see how that could add any insight to the issue. Maybe the motor/controller becomes "disabled" when it hits a big enough load? Of course you maybe right about the software - I've already had my share of frustration on that end.

[da40flyer]

Did you ever resolve this issue? My machine did this exact thing today.

Nothing has changed on the machine since I built it 8 months ago.