Steps per mm messing up Z-axis motors

So I am running on a Prusa i3 and at higher speed settings only one of my motors runs. When I lowered my steps per mm in marlin the issue went away. Do you guys think it could be a current issue or a motor issue?

Thanks

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sodonnell
When I lowered my steps per mm in marlin the issue went away.

Ouch!

There is only one correct steps/mm setting. You should keep that.

If a motor doesn't move, there is, assuming it's wired correctly, also only one likely cause: motor torque is lower than torque requirement due to friction and acceleration. Countermeasures (all work in the same direction):

- Lower friction by lubricating.

- Raise motor current (motor warming and stepper driver overheating is a limitation here)

- Reduce acceleration (a firmware setting, likely helps if the motor moves only a step or two)

- Reduce max feedrate (a firmware setting, likely helps if the motor moves part of the acceleration phase, then stops).

Marlin default settings for acceleration and max feedrate are known to be waay to high.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

Thanks Traumflug

After doing a bit more snooping around last night I saw information about acceleration and feedrate. That will be my first point of attack and I'll see how it goes. If that doesn't work I will probably have to dig into my pockets and get new steppers. Thanks again for the suggestions.

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sodonnell
I will probably have to dig into my pockets and get new steppers.

That'd be wasted money. It's almost impossible to break steppers. If you don't trust one of them, use them on another axis. Likely you'll see they work there just as fine as the other ones.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

Ok, I did swap it out for the more powerful motor from my extruder and when I homed my Z now only the more powerful motor moved. I also tried lowering my acceleration to 100 but the same issue came up. Also in pronterface trying to run it any faster then 100 mm per min causes one of the motors to either not function or jerk a couple times while the other motor moves at a regular speed.

I figured out my issue. My homing speed was too high. The highest speed I can go on my z-axis is 110 mm/min. Anything above that one of the motors will have trouble moving or stop completely.

Congratulations!

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Generation 7 Electronics	Teacup Firmware	RepRap DIY