Unusual behavior on Z axis

When I and move my z axis up and down, the stepper just chatters. Sometimes it does move, but the direction seems inconsistent. Click 1 time and the head moves down, click again in the same direction and it moves up. If I plug the z axis lead into the x or y axis header, it runs smoothly with no problems. What am I doing wrong?


It means you need to turn up the potentiometer on the zaxis driver,or your binding somewhere on the z. Is your anti backlash too tight?

Thanks for the response, Ryan!

I turned up the pot until the lead screw turns without chattering. Now the problem is just that it is inconsistent in its direction. For example, I turn the knob CCW once, and the screw turns CCW. Turn the knob another click CCW, and this time the screw turns CW. Another click, and the screw turns CW part way, and then CCW. I can’t see any rhyme or reason to how it decides which direction to go. I plugged the X axis into the Z axis on the board, and it controlled just fine, with no unpredictable behavior. Any ideas?


You turned it up too much. Please use a voltmeter and check the spec sheet for your driver and motor. Also double check your wiring might have a loose one.

I’ll check the wires. What am I looking for with the voltmeter? I got the motors from you. I don’t remember seeing a spec sheet.


Okay, I got it fixed. The short answer is that I’m using a terminal block to connect the 4-conductor cables from the steppers to the dupont connectors that plug into the ramps. Two of the wires for the z axis were clamped on the insulation instead of the wires. Works great now!

I looked up the model number on the steppers and got the data sheet. It said rated voltage was 4.2. I tested the power going to each coil of the steppers. The x and y axes were plus or minus 1.60v. The z axis was plus or minus 3.56v. Should be good, right?

Thanks for your help! I’m getting ready to tape a piece of paper to the work surface and let the machine write with a sharpie.



That should explain it for you. Its in the driver data sheet.