Printer randomly started making extremely uneven layers  

Re: Printer randomly started making extremely uneven layers

is this printed from the same gcode, or did you slice it again (with maybe some different settings) ?

this looks pretty weird.

can you check the two grub screws at the y-stepper pulley ?

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update: just noticed that you use an mk2s, so have a look at the u-bolts as well. they should hold the bearings securely in place... if there is some kind of slip, you might get such issues as posted.
to reduce possible slip, you can try to apply a small stripe (about 8 - 10mm wide) of double sided adhesive tape (the thick stuff they use for carpets) between bearing and u-bolt.

Re: Printer randomly started making extremely uneven layers

It looks as if your Z assembly has come loose, so the extruder can wiggle forward/backward?

Its kind of a neat effect though !

Re: Printer randomly started making extremely uneven layers

The gcode is the same between both prints. After messing around with it more I discovered I only have this issue with White Hatchbox PLA. I've run Hatchbox Blue, Green, and Black without issue. Does anyone have any idea why the white is giving me issues, and how to fix them?

Re: Printer randomly started making extremely uneven layers

Make any changes to your filament spool feeding? Binding and then releasing on the filament feed can cause the Z to shift some as well.

I had this problem, but to a lesser degree until I changed the filament holder over to ball bearing hub cones (look for parametric filament holders in Thingiverse).

Problem has gone away now.

I'm still going to move my spool from on top to behind (or to a shelf above) so that it is no longer bouncing on the frame at all. Some printing movements can cause some harmonic vibrations which will also cause a similar print defect.

Re: Printer randomly started making extremely uneven layers

The gcode is the same between both prints. After messing around with it more I discovered I only have this issue with White Hatchbox PLA. I've run Hatchbox Blue, Green, and Black without issue. Does anyone have any idea why the white is giving me issues, and how to fix them?

You could measure the filament diameter, maybe the white spool is (way) too thick, causing over-extrusion?

Re: Printer randomly started making extremely uneven layers

To me this definitely looks like Z-wobble, so check your Z axis first.
Maybe something came loose or got bended?

Re: Printer randomly started making extremely uneven layers

I printed these two parts back to back. I used the same gcode, and made no adjustments other than switching filament. I know it looks like z-axis wobble, but if that were the issue shouldn't I always see this? I am still pretty new to 3D printing, but to me the green part looks fine while the white has some layer shift going on.

Re: Printer randomly started making extremely uneven layers

For some additional information, I recently got OctoPrint running for my printer. If you look at the temperature history I see constant minor fluctuations of the hotend. I'm not sure if this fluctuation is normal, or if I need to pursue PID tuning.

Re: Printer randomly started making extremely uneven layers

I printed these two parts back to back. I used the same gcode, and made no adjustments other than switching filament.

Maybe the white one has overextrusion ?

Thomas

Re: Printer randomly started making extremely uneven layers

this fluctuation is normal

Re: Printer randomly started making extremely uneven layers

For some additional information, I recently got OctoPrint running for my printer. If you look at the temperature history I see constant minor fluctuations of the hotend. I'm not sure if this fluctuation is normal, or if I need to pursue PID tuning.

While it is normal, PID tuning will eliminate it.

Re: Printer randomly started making extremely uneven layers

People have noticed that the ideal temperature for a filament can depend on it's coloring, even from the same manufacture. Try printing a temperature tower using the white and see what the ideal temperature should be?

There are many available on Thingiverse. For example:

https://www.thingiverse.com/thing:2131069

Re: Printer randomly started making extremely uneven layers

His problem is not temperature. I can print PLA from 185 to 225 with basically no visual difference. Yes he would benefit from PID tuning and its a good idea to print a temp tower, but no amount of temperature variation will result in (or solve) what we see in those white prints.

He should measure his filament thickness. Take some calipers, and make about a dozen measurements of the diameter. Average them, compare between spools. TBH, to produce effects that bad, it would have to be way out of spec, but at least it would make sense.

Re: Printer randomly started making extremely uneven layers

Also check that the white roll is free to feed filament. Sometimes filament can cross over under itself on a spool and create periodic resistance to unrolling. This periodicity might cause something like this, but I agree it is more likely a roll with poor size control.