What are your thoughts on the cause of these lines?

What are your thoughts on the cause of these lines? This print was done with two perimeters, no infill. I think this is where the print makes the transition from doing the inner perimeter to the outer perimeter, but it shouldn’t be causing such a visible anomaly, right?

What you’re seeing there is likely z layer height change. Your nozzle pauses in that spot and causes that. Joris mode in Cura handles this kind of stuff nicely. It’s basically an option for continuous Z height change that Slic3r doesn’t support at the moment.

Also, that pattern you have there on the edge indicates that you probably don’t have your stepper drivers tuned properly, and they’re full-stepping themselves. If you tune your drivers a little closer to where they should be, you’ll get smoother perimeters instead of that staircase pattern.

It’s not the z-layer change, since when it changes layers it also changes the location on the perimeter where the new layer begins. I agree about my stepper drivers not being tuned, but I don’t know how to fix that.

@John_Schneider First, I seem to remember you replaced your z-axis leadscrew but did you adjust the steps/mm in firmware? Secondly this could be an issue with those old MakerBot motors you got with your printer so you could replace those. Third, probably before second but whatever, grab a multimeter and measure the reference voltage on each driver on the printrboard (black lead to ground red to the bottom pin of the adjustment potentiometer). Mine is set to x = 0.8, y = 0.57, z = 0.52, e = 1.095 although thats with different motors on x & z. You can adjust the potentiometer with a small screwdriver to get the proper amount of torque for each driver. (I had to turn some down and others up). Finally, hows that extruder working? Are you sure you are getting consistent feed?

@Brian_Evans , this print was after I had adjusted steps/mm for the ACME rod. Which motors are the old MakerBot ones? The z & x-axis? What did you replace them with? And I’ll have to pick up a multimeter and check the reference voltage. Wouldn’t have thought about that. That writeup of the tweaks you made to your Jr. can’t come soon enough :slight_smile: