PLA first layer problem: warp-droplets

I recently changed filament (1,75mm white, black eSun to light blue eSun, same seller) and for starters it worked perfectly well,
but quickly I got some problems with my first layer.
I tried a second filament (eSun again "gold" ('dark yellow'), same seller) same problem.

The problem is it's like droplets are forming on the surface, I guess the printed line warps, but as you can see,
the rest is working perfectly well. This part was printed without heatbed PID, but heatbed "BangBang" (my fault, fixed since)
so it gets some uneven layers but except the bottom layer, for me it is at least okay:


I have tried to:
* Lower speed
* play with temperature, it gets a little better with really high bed temp (70°C instead of 50°C / 158°F instead of 122°F)
* Fan: the lines warps so much they touch the +2mm heatbed inductive sensor
* Fatter layers, it became slightly less pronounced
* Naked bed, Blue painter tape, changing the tape
* Tuning Z-height, I went from squeezed layers to spaghetti, didn't change anything

I bought a batch from Alibaba.com, tried a glow in the night dark blue PLA, same problem (sorry
for the fuzziness but you can clearly see there is a problem in the middle of the print, but also
that the printing close to the borders seems okay):


And here is one with the 'gold' (carrot IMO ^^) coloured one


I uploaded it because IMO a piece of evidence is hidden here, look at the straight lines and when problems occur,
(the printer prints diagonally, parallel to the red lines)
short lines = no problem.
long lines -> the printed line warps / make 'bubbles' or droplets.



I thought it might be because I'm printing bigger parts (small, like a 20x20mm calibration cube works okay)
but this is an old black-eSun part with the later problematic 'gold' one to the left, if you zoom in you'll see that
the black is perfectly okay but the yellow one had huge irregularities:


Just for information, the prints end up, again IMO, perfectly well (top of the yellow one, sorry for the not very good photo):


My printer is a homemade XY-core alu frame printer, direct drive, ~40cm bowden E3D-V6 full metal extruder, NEMA17with microstepping, Atmega2560 + RAMPS, Marlin and I use slic3r and Repetier.
I use the Marlin version with Linear Advance (I tried without: M900 K0 and it didn't change anything).

So here comes the question :-)

How can I get that smooth first layer / what the heck is happening?

First make sure the bed is clean.
What does the top side of the first layer look like? If it's over extruding, lines will overlap excessively and the nozzle will tend to rip up previous lines. The top surface of the first layer will look very rough. This can happen if the nozzle is too close to the bed, too.

Are you using Z-lift on retract? It may be that the bed isn't returning to the same Z position when it sets back down.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

At first I thought, you've set the nozzle height wrong. But you said it's already tested.
Then there is a chance of slicing the 1st. layer with a lower layer-width setting.
On some printers I print with 100%, others 130% or 170%. Default in slic3r is 200%
It's definitely worth playing with this setting.

Thank you for your help!

The bed is clean (changed blue-tape), I don't think there is over extrusion (no elephant foot, all other layers okay, I tried lowering extrusion settings but got underextrusion problems).

On the first layer, if I don't use excessive heat and so, and the lines are longer than around 20mm, they'll unstick from the bed and warp up. This is the actual problem so I tried higher temp which mitigates the problem but doesn't solve it.

I do use Z-lift on retract, I'll try without. Should I disable linear advance too (have tried just without LA, didn't change anything)?

I will also play around with first layer height, but as I said, fatter layer is helping a bit but it doesn't seem to solve the underlying problem.

Witt re-check that the z tuning is perfect too as all my fixes would also help a badly adjusted z-level...

I printed the "Benchy" boat, went okay but the bottom squashes out the "CT3D.xyz" text, tried a tenth of a millimetre higher Z level -> printed in air.

Tried a slightly lower extrusion (1.03 -> 0.98) and the print is slightly better (maybe) but the first layer is clearly better. Tried a flat swuade, really better too! I'll continue trying and tweaking!

When there is more or less to print (for example the deck is printed up to say level20, and then it's not printed any more), the hull clearly shows it:


So I guess that's also an indicator of over extrusion (also there is an I guess obvious elephant foot in the bottom?).

There is no smoke stack on the model as, for what it seems, my PSU blew mid print (ok at the end ^^), no 12v, no motors (but temp shows up, guess the 5v over USB still works :-) ) no fans turning any more so I'll be back when I have fixed that.

Cheers and thanks for the help :-)

I wasn't talking about layer height, but layer width.
Nevertheless, I babystep my nozzles in 0.02mm increments. That is 5 steps between 0.1mm ( the height correction you seem to use )
Using higher temp is just a band aid for another problem: constant filament temp. Did you run a PID tuning yet?

Quote
Ludvig
I printed the "Benchy" boat, went okay but the bottom squashes out the "CT3D.xyz" text, tried a tenth of a millimetre higher Z level -> printed in air.

Tried a slightly lower extrusion (1.03 -> 0.98) and the print is slightly better (maybe) but the first layer is clearly better. Tried a flat swuade, really better too! I'll continue trying and tweaking!

When there is more or less to print (for example the deck is printed up to say level20, and then it's not printed any more), the hull clearly shows it:

So I guess that's also an indicator of over extrusion (also there is an I guess obvious elephant foot in the bottom?).

There is no smoke stack on the model as, for what it seems, my PSU blew mid print (ok at the end ^^), no 12v, no motors (but temp shows up, guess the 5v over USB still works :-) ) no fans turning any more so I'll be back when I have fixed that.

Cheers and thanks for the help :-)

Thats not elephants foot, you are overcooking the bottom layers.

Ditch the painters tape.

Laydown a layer of gluestick.
Recalibrate your nozzle height for no heat.

Test.

I doubt you really need any heat with PLA (I dont use any), but set it to 30C max for pla.

The unevenness could also be occurring because of too much retraction, for a all metal E3Dv6, try 1.5-2mm retract, not the default 4 or 5.
I used a retract test print form thingiverse to help me get close. Small cubes dont usually test or show retract probs. Too much retract will cause the E3D to jam, and let me tell you that sucks.

Good luck.

Quote
orbitalair
Thats not elephants foot, you are overcooking the bottom layers.

Ditch the painters tape.

Laydown a layer of gluestick.
Recalibrate your nozzle height for no heat.

Test.

I doubt you really need any heat with PLA (I dont use any), but set it to 30C max for pla.

The unevenness could also be occurring because of too much retraction, for a all metal E3Dv6, try 1.5-2mm retract, not the default 4 or 5.
I used a retract test print form thingiverse to help me get close. Small cubes dont usually test or show retract probs. Too much retract will cause the E3D to jam, and let me tell you that sucks.

Good luck.

Thanks!

Yeah repeated heat creap broke my first cheap "E3D" made of chinesium, one especially bad one made me break the heatbreak in two

So I tried without painters tape but I don't have a glue stick (had the flu all week so no going out), so I put it back.

Heatbed Low/No temp -> no changes. Already have 1.7mm z-retract, no z-lift.

I tried to print with less extrusion and well, it gets better at 50% (!) but then the other layers are too thin obviously, and the problem is just mitigated, sometimes it worked, sometimes not.

So after a lot of hours tweaking and testing, I decided to do a full check up, extrusion length, anything that wobbles etc. and to no avail.

I even removed my cold end fan (you never know...).

Restarted from scratch with default values too, nothing. I can almost throw any temp, speed, overextrusion, underextrusion and the pieces comes out great, except for that first layer??!!

Then when I stuck my head in the printer to try to grasp some information (for the hundredth time), there is a lot of stuff and the printer moves around so it's hard to get clear view, I found it...

It's the E3D V6 Silicon sock that had been burnt/damaged a little bit, so one of the sides, just beside the nozzle (on the backside, so well hidden), was lower than the nozzle and touched the newly laid down lines... like almost not at all but enough to, if the line was long enough, trouble it.

Cut away the incriminating part with a cutter, and now it works perfectly well again!

Well, what do you know? Sometimes its the oddest thing that causes a problem isn't it.

Glad you got it fixed !!

A year ago I sent a mail to E3D about the problems I've had with these silicone socks.
I even told them what I did with these socks : Were the brass nozzle sticks out I enlarged that hole to about 12mm(1/2"). Problem solved.
Last week I ordered a new set of these socks and guess what : the nozzle hole of the new batch silicone socks have much larger holes now.
I was probably not the only one having similar problems.

I did like you, cut out some 10mm diameter hole.

Nice they fixed it, I guess I'll have to buy some new ones now :-) must just use up the one I have, doesn't seems like there is much wear and tear on it.