Weird printing texture

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kekmi
Posts: 9
Joined: 21 Jun 2016, 10:53

Weird printing texture

Post by kekmi » 25 Jul 2017, 16:07

Hey,

Just recently I started to experience weird texture appearing on the right side of my prints and I can't seem to find the cause. Let's start with a pic, sorry for the bad quality but I'm talking about those weird tree branch like waves on the side there :)

Image

Other sides of the calibration cube are almost perfect but this right side (Y-axis) gets this weird texture with clearly visible "waves" and crevices. It looks like it is missing material from between the waves.

Might this be a case of "ringing"? For me it seems like ringing from bed movement but shouldn't it be affecting the other sides too? I did tighten the y-axis belt a bit which was a tad bit too loose but that had no effect whatsoever. Could bed vibration cause something like this for just one side since I'm pretty sure the bed is vibrating a bit too much on certain movements.

Some expert input would be appreciated to help me solve this tiny yet annoying problem. The prints are so close from being almost perfect!

MrDoom
Posts: 223
Joined: 01 Apr 2017, 10:01

Re: Weird printing texture

Post by MrDoom » 25 Jul 2017, 16:34

Hello, how many outlines/shells are you using? and are you printing them inside out or outside in?

It seems to me that when it changes layer it begins in that corner on the exterior shell and the extrusion hasn't yet stabilized. I would set the perimeter to print inside out and make the infill first then the perimeters, that makes sure the extrusion is constant when it reaches the exterior of the part

Make sure you have you retraction set at 1-1.5mm at 15mm/s, I know it seems low but works flawlessly and causes way less problems than the original values :)

kekmi
Posts: 9
Joined: 21 Jun 2016, 10:53

Re: Weird printing texture

Post by kekmi » 25 Jul 2017, 18:10

Ah-ha!

That might just be it! I'm printing with just 2 outlines and the outer shell is very fragile, I can peel it off with gentle swipe of my nails which surely seems like under extrusion now that you mentioned this hehe :P . I also tried printing the same object rotated so that the problematic side is not parallel to Y axis and it seems like the issue somewhat lessened and the weak wavy part is now only at the corner with slight crevices along the side.

Got to try those you mentioned. I was using Cura though, not sure if you can even change the shell order there. I think I'll try Slic3r with same settings too to see the difference. My retraction was already pretty low 1,5mm with 20mm/s but will try lowering it a bit more.

Thanks plenty MrDoom!

MrDoom
Posts: 223
Joined: 01 Apr 2017, 10:01

Re: Weird printing texture

Post by MrDoom » 26 Jul 2017, 10:18

No problem :) I'll be waiting for some feedback

kekmi
Posts: 9
Joined: 21 Jun 2016, 10:53

Re: Weird printing texture

Post by kekmi » 26 Jul 2017, 17:40

Update:

So I downloaded the newest Cura 2.6 and printed with the same settings as before except 1mm retraction with speed of 15mm/s. The result was A LOT better but there is still clear under extrusion on one side mostly at the very corner where the print head starts. This time its on the front side which is just because in this iteration of Cura the print head decided to start there.. so it is clearly a problem with having enough pressure to keep the filament flowing after retraction moves. Should I keep lowering the retraction or fiddle with some other settings perhaps? I'm worried that my prints start oozing a lot with such low retraction :) Also, it was hard to tell if the outer wall was printed first or last but the settings seem to be set to print inner walls before outer walls. Though, as the wall consist of just 2 perimeters, could the slicer be still printing the true outer line first since they are both actually outer walls? :lol:

I'm currently printing PLA 210c with speed of 20mm/s and 0.1 layers. Shells are 0.8 thick and the retraction settings as mentioned above (1mm and 15mm/s). Also I'm using 84% flow atm which I calculated after calibrating my E-steps. The result of last calibration block was spot on 19.98mm x 19.97mm x 12.05mm with 1.01mm walls (STL dimension 20x20x12 and 1mm). Now only if I could get the filament flowing at the start of the layers to fix that one ugly wall! :(

PS: Tried Slic3r for Prusa but it sliced the cube in a very weird way that resulted in lots of under extrusion on the bottom and missing all 4 corners. I think I stick with the new Cura heh.

MrDoom
Posts: 223
Joined: 01 Apr 2017, 10:01

Re: Weird printing texture

Post by MrDoom » 27 Jul 2017, 14:24

First of all are you using the latest firmware the 1.1.1? there were some improvements in print quality such as pressure control that maintains a more steady flow before and after retractions and allows even smaller retractions I've been using 0.8mm without any issue ever since.

Slic3r does require a bit more tuning to get good results but in my opinion once you get the hang of it it's better.

Keep in mind that every filament color requires a different extrusion multiplier sometime up to 10% more due to the elasticity and other properties of the material. Adjust that while printing on the "Tune" menu of the printers LCD.

About Cura settings try this on Cura 2.6 go to Preferences>Configure Cura> Setting
On "Shell" tick the boxes:
Wall Line Count
Outer before Inner walls

On Infill:
Infill before walls

On Material:
Retraction at layer change
Retraction extra prime amount

then you should be able to increase the number of outlines, I would recommend 3 for the best result and disable the outer before inner walls if it was enabled.
Enable the Infill before walls setting.
Disable retract at layer change and if that still doesn't work try putting 0.2 on the Retraction extra prime amount.

After all this that should be fixed :D

kekmi
Posts: 9
Joined: 21 Jun 2016, 10:53

Re: Weird printing texture

Post by kekmi » 29 Jul 2017, 17:08

Updated to firmware 1.1.1 no real difference with just that. Then I adjusted my flow rate a bit higher to 90% and made the changes you mentioned. It got a bit better but still too much gap around the first corner. Perhaps there is something with the hot end or my filament.

So after that I went ahead and set the start point to random and voila, now there is no clear gaps around one side, just few barely visible holes and blobs in few random places but this will do for now as those can be sanded away easily or melted with hot air gun. Now I know how to start fine tuning this and learned plenty. Thanks again MrDoom!

MrDoom
Posts: 223
Joined: 01 Apr 2017, 10:01

Re: Weird printing texture

Post by MrDoom » 31 Jul 2017, 10:43

Nice to know that it's working :)

Btw I use the flow at 100% or above most of the times otherwise there is too little extrusion, after updating to the new firmware don't forget to go on the menu "control > Restore failsafe" to load the new settings otherwise I think it uses the configuration from the old firmware :)

kekmi
Posts: 9
Joined: 21 Jun 2016, 10:53

Re: Weird printing texture

Post by kekmi » 31 Jul 2017, 13:21

Ah thanks for info. I notice considerable under extrusion on few parts after the upgrade even at 95%. Like very thin gaps between lines on layers. Got to try upping it to 100% again :D

MrDoom
Posts: 223
Joined: 01 Apr 2017, 10:01

Re: Weird printing texture

Post by MrDoom » 01 Aug 2017, 10:35

By my understanding the original firmware was overextruding a lot, at least for me now I use pretty much always 100-105 depending on the color and get awesome finishes :)

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