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I recently changed filament and for starters it worked perfectly well, but quickly I got some problems with my first layer. It's like droplets are forming on the surface (finished item + 3 undersides):

enter image description here

The final part is (for me) okay but I'd like to get rid of those pesky 'drops'.

As the defect is quite stable and quite recognizable and it happens all the time, I bet somebody more experienced than me knows what's going on!

Info:

I'm using a 1 week old eSun filament, a E3D V6 Hotend 1.75mm on my scratch CoreXY printer, short Bowden direct drive, Repetier, Marlin, Linear advance (M900 K60 so quite low).

The print is done using a 0.4mm diameter nozzle at 0.2mm height at:

50°C(122°F) heat-bed and 214°C(417°C) hot-end for first layer, then lower a bit to

40°C(104°F) heat-bed and 211°C(412°F) hot-end.

I use Blue-painter tape.

Worked perfectly well with my black eSun and my white eSun.

What's my problem?

Thank you all!

[Edit]

Tried about everything (more temp, less temp, fan on item, more / less bed temp, underextrude, moving around z delta, removing linear advance, radically lowering speed) but the only thing that worked about okay (problem was quite reduced but didn't go away totally) was to bump up the layer thickness to 0.3mm

[Edit 2] Finally it seems it was, as it usually is, a conjuncture of several problems that I will list here:

  • The bed was not perfectly flat
  • The heatbed moved/bended when going from a hot first layer to a colder second (and on) layer
  • Maybe the speed was a bit high for the first layer (25mm/s)

I fixed this by installing a borosilicate glass bed on top of the heat bed which ensures a perfect flatness.

I had to change my inductive sensor to an 8mm one (insteéad of the 4mm I had previously added) to make this function. I think it is not as good as it can be as it detects the heatbed under the glass (which is not perfectly flat), but it's enough for now. I'm thinking about how to make the glass conductive, like aluminium or something, but that's for another day/post.

I also put blue tape on the glass because the first layer was tricky. This might be because the inductive sensor doesn't do its job that well (see above).

Heatbed temperature for first layer: 70°C

Extruder temperature anywhere from 190°C to 220°C works fine, that was not the problem, or it is no longer a problem.

I also lowered the first layer speed to 20mm/s because the first layer didn't stick easily directly onto the glass, with blue painters tape it sticks even too much so I'll try higher speeds. It did mitigate problems though so it might be a path to try if you run into similar problems.

And now it seems that it works even amazingly well, I just have to print something really big to see!

---------------Old:

Moving z up made spaghetti :-) and different temperatures made quite extreme warping:

enter image description here enter image description here

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  • $\begingroup$ What's the step size in the Z axis for your printer? $\endgroup$
    – mbuc91
    Feb 2, 2018 at 4:54
  • $\begingroup$ I used 0.2mm getting these problems, 0.3mm works better but still not perfect. Or maybe you are wondering about the setup? It's a classic nema 17 with microstepping and a "lead screw" (cpc.cx/ld0) pushing a cantilever build plate running on two vertical 8mm (IIRC) rods with (2+2) linear bearings. $\endgroup$
    – Valmond
    Feb 2, 2018 at 11:19

2 Answers 2

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Mine is more of an educated guess than a definitive diagnosis, but it looks to me like if your printer may be overextruding (it's difficult to say with certainty with this particular picture, but your top layers too do not look as good as they should).

I wonder if you have calibrated your extrusion for this particular spool of filament? This is something that you should do for each and every new spool of filament, regardless of whether you have already used the same brand and material, as different batches and colours may differ slightly in diameter or hardness, and both factors can lead to a different overall flow out of your nozzle (I just checked eSun website, and they state "Accuracy:1.7-1.8mm", and 6% variance is quite a lot).

Possibly unrelated, but 211+°C is also quite on the high end of the correct temperature for printing PLA (if that is what you are using). Still in the range recommended by the manufacturer - so it should be ok - but you may wish to try bringing it down a notch (205°C perhaps?).

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  • $\begingroup$ Hi @mac thanks for answering! For the overextrusion, I'll try but the rest of the parts (after the first layer) are quite perfect (thin walls are right size and so on). Calibration goes with this but it's really close to 1.75mm diameter. I'll try lower temperatures but I already had bad adhesion between layers with lower temp, maybe I need "high" extrusion temp but lower bed temp? Will try. $\endgroup$
    – Valmond
    Jan 30, 2018 at 22:45
  • $\begingroup$ @Valmond - As I said, mine is no more than an educated guess, so I may still be wrong. Keep in mind though that even a massive overextrusion of 10% would only translate in 0.04 extra millimiters on a thin wall, which is below the accuracy of most calipers (0.05mm). More in general, over-extrusion is typically only a problem on bottom and top layers and if you print with 100% infill, otherwise a typical print (2-4 layers of shell + infill < 100%) won't be affected much, as the excess plastic will simply be pushed around slightly. That said: I may still be totally wrong! :) $\endgroup$
    – mac
    Jan 30, 2018 at 23:03
  • $\begingroup$ If both black and which filaments give you no problems, then maybe the colorant (beautiful color btw) is changing the print qualities a bit. I would definitely calibrate your extruder, then I would try lowering print temperature a bit and fiddling with live z. Your live z may be a teeny bit close to the bed. $\endgroup$
    – ctilley79
    Jan 31, 2018 at 15:33
  • $\begingroup$ Additionally, you shouldn't need tape for PLA. $\endgroup$
    – ctilley79
    Jan 31, 2018 at 15:37
  • $\begingroup$ @ctilley79 Yes it's possible this new beautiful color is somewhat different. I'll fiddle around and report back, but your comment about being close to the bed hit me, I am and it's great for getting that first layer down because my prints warps a bit when they start with an over hang... I'll check that out, thanks! $\endgroup$
    – Valmond
    Jan 31, 2018 at 16:32
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First of all, thanks for all the help, it really is a nice community!

But none of them actually helped and I finally find out what to actually do to fix the problem so here it goes:

  • Extruder temperature didn't change anything (made it worse under 190°C/374°F)

  • Speed didn't change anything (tried as low as 10mm/s)

  • Z tuning didn't change anything

  • Using 0.3mm layers instead of 0.2mm made it slightly better but still completely unusable

So, what did the trick?

I figured that it was extreme warping, so heating up the heatbed to 80°C/176°F and the first layer comes down really good, for the rest of the print I use normal temperatures and it works okay. For overhangs I bump some degrees and point a small squirrel cage fan on the overhang.

I think the filament is damaged or that this particular color might be a bit different than other colors, but well, now it works!

[Edit] From a recent firmware upgrade the heatbed PID was disabled, re-enabling it really made it simpler too.

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