Replaced Stepper Motors: Z axis issues

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M4df4c3
Posts: 5
Joined: Tue Feb 23, 2021 5:02 pm

Replaced Stepper Motors: Z axis issues

Post by M4df4c3 » Tue Feb 23, 2021 5:22 pm

Hello,

I bought a I3 Pro B from a friend and noticed the previous rods where damaged due to lack of lubricant. I purchased new stepper motors (310mm lead screw length, 8mm diameter, 1.8 degree step angle).

I installed the new motors and steppers can move the extruder carrier up and down without issues.

But the issues starts, once I begin a print. The first layer prints perfect, and then once it begins the 2nd, 3rd, etc. layers, the z axis hops too high, and the layers are too far apart. When the print is finished, it looks like a stretched accordion; very tall, very flimsy and barely intact.

In control, I tried changing the z steps per mm setting from 2560 down to about 2100, this helped slightly, but the setting always resets, and it take over an hour the manually click the LCD button down 500+ steps (I think it needs to be at 1600 or less).

The grooves on the new threaded rods are much thicker than the old ones, so I understand what the problem is. I just hope I don’t have to replace them again. I also cannot find rods with as small as grooves as the originals.

It there a way I can set the z steps per mm in Repetier Host? Or is there another way to changes the z steps per mm? Perhaps in the firmware using Arduino IDE?

Thank you, I am having lots of difficulty with this, anything helps!

-Tony

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