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Prusa Mendel Iteration 2 Stepper Motor Z Issues

Former Member

     So I bought all the components I need to make a PMI2 and put it all together, being sure to measure multiple times so it can be accurate as possible. The only issues Ive had are the electronics, mainly the stepper motors. They're have some slight binding issues which are really apparent on the Z axis. I check all the angles that have to do with it and they are really accurate. I also have the rods lubricated and adjusted the power output to max for the stepper motors. The thing is I don't think that the Z motors are receiving enough power, considering that they are connected together. I've had it sitting for a few months now and I have yet to print anything.

 

     If anyone has a PMI2 or know how I can fix the issue that would be a lot of help. Thanks for taking your time to read this. image

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  • I would check to make sure the steppers are wired the same way (even in batches from the same manufacturer, you can find occasional variations), then try applying power to one motor and then its mate - watch for rotational phase or micro-stepping conflicts between each. Binding can definitely be an issue if overly constrained (both ends, etc) when using metal bushings or thrust bearings. You can test by loosening the bearing and allowing it to float while testing the motor. You can also apply small heat sinks to the A4988 chips to help dissipate heat if it starts to work and then stops - thermal failure can be tricky to identify sometimes.

     

    Kirk

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  • I would check to make sure the steppers are wired the same way (even in batches from the same manufacturer, you can find occasional variations), then try applying power to one motor and then its mate - watch for rotational phase or micro-stepping conflicts between each. Binding can definitely be an issue if overly constrained (both ends, etc) when using metal bushings or thrust bearings. You can test by loosening the bearing and allowing it to float while testing the motor. You can also apply small heat sinks to the A4988 chips to help dissipate heat if it starts to work and then stops - thermal failure can be tricky to identify sometimes.

     

    Kirk

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