Z motor gets stuck?

Hi. I'm hoping someone can help me with this problem I have. I'll start a print from the SD card and the printer will move normally but when it's time for the extruder to go down, one of the z motors will stop moving and make a loud buzzing noise. This just causes a lot of headaches since the other z motor is continuing to operate. I've printed perfectly fine on this printer before and this doesn't happen when I move the motors through Pronterface. What could be the problem? Any suggestion would be appreciated.

Moving in Pronterface but not during a print is usually a sign of the max Z speed set too high in the firmware. Are you using the firmware I provide?

What speed is set in pronterface and what speed is in the firmware? Note the former is in mm/m and the latter in mm/s. They are normally set to 240 / 4.

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[www.hydraraptor.blogspot.com]

Yes. I'm using the firmware you provided and only changed things for calibrating. I don't think I've touched the speed settings at all.

The speed set in pronterface as you can see is at 240 and the firmware shows 4.



I also took a video to give you better view of what's happening.
[youtu.be]

I'm looking around skeinforge and i do see the maxium z feedrate in the speed tab to be set at 8mm/s. Could that be the problem?

No, the firmware should limit the speed so it doesn't matter what the slicer sends. Slic3r even relies on this and doesn't attempt to limit the Z speed.

If you set the speed in pronterface to 480mm/m and move it what happens?

You could also try reducing the speed in the firmware to 3 mm/s to see what it happens, but all other Mendel90s work at 4.

Is the axis free to move? If the Z bars aren't exactly parallel it might struggle. You could drive it to the bottom and then loosen and re-tighten the right Z motor bracket and then drive it to the top and loosen and re-tighten the right Z bar clamp to ensure the right bar is parallel to the left.

Have you put any oil on the lead screws?

Edited 1 time(s). Last edit at 08/05/2013 05:11PM by nophead.

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[www.hydraraptor.blogspot.com]