Any Ideas to remove ripple effect?

Hey there,

Just wondering if anyone has encountered this ripple effect with their Mini and managed to get rid of it?

The problem can be seen in the picture attached. From left to right:

  • Original octopus supplied with the Mini printed at the factory (No Ripple)
  • 1st print with the included HIPS on Normal quick print (Some Ripple)
  • PLA Normal quick print (More Ripple)
  • PLA @ 0.05 layer height and slightly slowed. I downloaded the PLA fine profile from LulzBot and slowed it and decreased layer height. (Lots of Ripple)

The frequency of the ripple doesn’t increase with the number of layers - so I am a bit baffled.

Any suggestions? - Otherwise pretty happy with it :slight_smile:


Bent Z-Axis threaded rod?

Try to run the head up and down in Z and see if the head wobbles left to right as it travels up and down. There is a calibration burnin gcode file that should be of help for this.

I have not had to do this for a couple months now. As it runs up and down look at the outside edge of the threaded rod by using the the outside edge of the smooth rods as a reference.

If you see nothing then I have no idea.

It seems a Z axis issue is more likely considering the periodic nature of the banding, but dealing with that might be pretty difficult if it can’t be resolved by checking for loose set screws in the coupler (one to the motor, one to threaded rod). I did notice two things about the pieces though, and it might be worth trying some other easy things first:

It could just be the lighting, but it looks like the face of the objects show less banding than the sides. Perhaps you have a loose belt or set screw on the X or Y axis. This shows how to tighten the belt: The manual gives much the same info: It doesn’t say how tight to make the belts though, just to not over tighten them. I have been wondering about the correct tightness myself.

If you look at the bottom of each piece, the part that touches the buildplate, you see that there is some extra extrusion around the entire perimeter of the pieces you printed, and not on the factory piece. If it is over extrusion, measuring the filament diameter with calipers and adjusting that number might help. You can also adjust the flow rate. You have to do this in expert settings. There’s also the initial layer width option you might want to check – the default is 125% but I would think that would affect only the initial layer being a little over extruded. Assuming the factory piece was printed with this 125% first layer, you are now getting a lot more filament coming out than they did at the factory, probably over the entire print.

Also your build plate might have loosened. Do the edges perpendicular to the X axis wiggle up and down? Mine did after a while, just remove the print surface and tighten up the screws underneath that attach the plate to the carriage. I don’t think this would make the regular banding you see, I think it would look more random, but it’s worth checking because it takes only a second.

Thanks both of you for your replies!

After printing another square piece in green ABS it seems the z-axis ripple effect is only present in one dimension! Only on surfaces perpendicular to the x-axis.

I have inspected the screws and nut I can find and they appear tight - belts appear tight.

2 slight inconsistencies I noticed

  • The x-axis belt driving pulley head does not appear to be centred
  • There appears to be a slight wobble in the threaded z-axis bar

I am uploading videos of each of these so you guys can take a look to let me know if you think its the cause - or just a red herring.

Your continued attention is appreciated…


Here is a link to a video of the x-axis motor spigot - which to my eye looks slightly off center when rotating…

The other suspect one is the right-hand threaded bar looks to have a slight wobble when rotating:

… and close up:

Could any of these things explain the rippling of vertical surfaces perpendicular to the x-axis?


IMHO the problem seems to be because the z axis threaded bar is a little bit bent (If this is the problem you would need to replace it).Also check if the connection with the motor is centered and tight as it was adviced before.

I don’t see wobble in my printer on the Z axis. Your X axis pulley wobbles more than mine – I have a little wobble, but I had to really squint and repeatedly run the print head back and forth to see it. On yours it is obvious right away.

If it is still under warranty I would contact them about the wobble in that Z rod.

hemocyanin - Thanks for taking the time to compare my videos to your own machine. Good to know if the wobble is normal or not.

kmanley57 - Thanks for the advice about the z-axis threaded bar. I have sent an email to support to see what they say.

eteson - thanks also for your input


Hey there,
I would just like to follow up this post by letting you know that LulzBot support came to the rescue, confirmed a bent z-axis threaded rod - these things happen, but what is important is what is done about it. In LulzBot’s case they returned and replaced the printer, and even though they didn’t have to, covered the shipping. Great support response in the face of a difficult situation and I would continue to recommend LulzBot to anyone I meet.

Thanks guys!


Love the double fisted roctopus – where can I get one?

Here -