Stepper motors keep starting and stopping

[JAZZCNC]

Wondering if anyone knows why my stepper motors keep stopping and starting when a program is running but in jog mode they run fine. Only new so Mach3 might not be set up ok.

Not giving us much to go on here Davo we are not Mystic Meg's.? Could be lots of things.

Explain better exactly what happens ie: Does it stop completely or stop/start. On which axis and at what point of travel on machine, same place or random spots. When or where in the code, beginning, middle end.? . . . . Video better still.

Give details of the Motor tuning in Mach3 for each axis.
Give Info regards drive model and Micro stepping, PSU voltage, motor size/model.
Parallel port or external motion control.

Give some indication to size and type of machine.

[Davo242]

[Chaz]

The vid is not watchable and the pics too small. Dont use the 'save locally' option, it makes the pics tiny. If you can get the vid on utoob, it will help.

[Davo242]

https://youtu.be/rbJveQTkICA this is a link to a video of the motors

[Davo242]

hope these are ok

[JAZZCNC]

Ok well first turn the Kernal speed sown to 25000hz you don't need it that high. Going to high here stresses the parallel port.

Next the fact you are testing on the bench and not fastening the motors down will cause resonance which could be some if not all of the problem.

Also the Steps per setting how did you come to the figure of 320.? . . . . And What are Micro steps set to on your drives.?

Are each axis set to the exact same step per figure and tuning.? You must select the Axis on the side bar to correctly display for that axis and then save after every change.

[Davo242]

Thanks for replying

Ok I will try fastening the motor to the frame tomorrow to see if this corrects the problem.

The steps per setting I have used is what was outlined in the illustrations provided with both the motors and drivers. The micro steps are set at 1/8. On my drivers this corresponds to off on off.

Yes I have checked each axis and they are correct.

I will try and upload pictures of driver.

Once again many thanks for your time and patience

[JAZZCNC]

The steps per setting I have used is what was outlined in the illustrations provided with both the motors and drivers. The micro steps are set at 1/8. On my drivers this corresponds to off on off.

Ok well 320 is ok but it should be worked out accourding taking linear pitch into account. With 1600ms then 320 would mean 5mm pitch. If your not using 5mm pitch and just bench testing then try 160 in steps per which would be like 10mm pitch and it's less work for the Parallel port to reach the same velocity.

This won't be your problem but it's a good starting point.

To help the parallel port you could also turn the micro stepping down on the drives to 1/4 (800ms) and set the Steps per 80.
Some times due to resonance you have to play with the MS to find best setting to match your motors. The quality of the drives plays a big part here and also how ridged the machine is. Hence why often Steppers don't work well on the bench.!!

EDIT: Ok well after seeing the drives then I'm not one bit surprised. Sorry to say this but they are Cheap nasty units which won't have much if any resonance handling capabiltys so it's no surprise motors are complaining.! They also often have slow electronics so it could be a timng issue.

One thing I've seen work before with these cheap drives is to toggle the Step low Active setting. (it's technical so won't get into why, just try it)
Also playing with Step Pulse Dir Pulse may be needed because the Opto's could be Slow so the Step pulse needs widening.
First try setting the Step pulse to 5 and Dir pulse to 0 and see what happens then if no change then toggle the Step Low Active.

[Davo242]

ok i attached the motors to the cnc and still no change. i aslo have change the ms to 1/4 and 80. still nothing.
where can i find the step low active setting.

[Davo242]

These are the drivers which are being used on the motors. They are set for 3.3 a