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Suddenly, my printer has started producing prints that have a very pronounced layering. Normally, the alignment between layers is very good, and the prints look very smooth. Suddenly, the prints have become much worse and the layers are misaligned with respect to each other.

enter image description here

The part on the left is my "normal" quality, while the part on the right show the deterioration. Here is another picture (in which the good part is on the right):

enter image description here

The parts are both printed with 0.1mm layer height, and identical slicer settings/filament. I am printing on a custom-built FDM printer; the mechanism is roughly similar to that of an Ultimaker.

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    $\begingroup$ Can you provide before and after images of the same model, rather than two different models, hopefully with better focus on the ridges themselves? $\endgroup$ – Adam Davis Jan 13 '16 at 13:59
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There are many factors, here are a few things to check:

I'd first suspect filament feeding. This type of ridging can be caused by a filament coil that is binding occasionally, or a filament that doesn't have an even diameter or volume per length. Binding within the filament feeder and feeder tubes can also be a cause. Bubbles in the filament, or sometimes a mismatch between the filament ideal temperature and the head temperature could create results like this, but it probably wouldn't vary so much between the layers.

Next I'd look at the print head. If it has blockages, or poor temperature control this could result.

Lastly, I'd check the mechanisms - disconnect the motors and see if all the carriages slide smoothly without any binding, particularly the Z axis. It doesn't look like you're missing steps, but binding here may result in greater backlash, which could result in similar ridges. Make sure any belts and gears are tight.

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  • $\begingroup$ Nice answer, though you've not correctly identified the issue :p $\endgroup$ – Tom van der Zanden Jan 13 '16 at 14:33
  • $\begingroup$ @TomvanderZanden Is this ABS, and printed in an enclosure with no fans or drafts? $\endgroup$ – Adam Davis Jan 13 '16 at 14:48
  • $\begingroup$ That is correct. The only fan is the one blowing on the cooling fins of the E3D hotend. $\endgroup$ – Tom van der Zanden Jan 13 '16 at 14:57
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As with many topics in 3D printing, there can be many variables that produce this result.

Immediately, your images make me think that the belts on your machine are not tight enough. This can cause noise in every direction of movement and is more prominent in backlash areas. I would suggest going through your general maintenance checklist:

  • Replace Build Plate tape
  • Level build plate (An uneven plate or improper height can yield these results as well)
  • Teach your axis belts
  • Clean/lube guide rails
  • Clean drive gears

Keeping up on your maintenance (I do mine about every 5 prints) should reduce noise in your motion and ensure better quality prints, mechanically speaking.

As mentioned above, your results may be caused by your BP being leveled too low (or too high). If your build plate height is off, the filament will not adhere to previous layers very well (if too low) and can cause this back and forth "spaghetti noddle" effect on outer layers. If the build plate is too high, you might see the nozzle physically "spreading" the previous layer around as the nozzle digs into the layer.

Another possible fix for this would be to play with the settings in your slicing engine that involve the order that shell/roof/floor layers are printed. ie Start inside-out or start outside-in.

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  • $\begingroup$ The first thing I would try is to increase the distance between the nozzle and bed on the first layer through bed leveling or auto probing configuration. $\endgroup$ – Tormod Haugene Jan 13 '16 at 21:07
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    $\begingroup$ I suppose it could happen either way, high or low. I've mostly seen my machine print like this when its too low. But I've watched it was too high and seen the nozzle dig into the previous layer and spread it around. $\endgroup$ – tbm0115 Jan 13 '16 at 21:11
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    $\begingroup$ @TormodHaugene I changed my explanation a little bit. Thank you for the attention to that detail. $\endgroup$ – tbm0115 Jan 13 '16 at 21:43
  • $\begingroup$ Nice improvements! I think your answer is all around very good. $\endgroup$ – Tormod Haugene Jan 13 '16 at 22:04
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It appears the heatbreak of my E3D nozzle had worked itself loose from the heatsink, allowing the nozzle to wobble around a bit. Because the nozzle was still tight against the heatbreak I didn't experience any issues with my hotend, but because the heatbreak was slightly loose the nozzle wasn't properly constrained and moving around a bit.

A quick turn to tighten the heatsink back into the heatbreak was enough to fully resolve the issue. My prints are as smooth as ever now.

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    $\begingroup$ I would suggest marking this as your answer in case this is happening to someone else. That's something that I wouldn't think to check right away. Glad you figured it out! $\endgroup$ – tbm0115 Jan 13 '16 at 22:07
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Have you recently leveled your print bed? By placing the nozzle too close to the bed on the first layer the first layer will seem over extruded. If there are no infill layers after the first layer, these layers will seem over extruded as well since the extra filament will have nowhere to go.

A typical sign of too close bed leveling is that the bottom layers seem over extruded, while layers after regions of infill appear normally extruded.

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