eSun ABS+ problems with .2 layers  

Re: eSun ABS+ problems with .2 layers

So this is almost too strange to believe, but the final setup that worked was adding 40% fan after layer 5!

It makes no sense to me, its just tented and not actively heated in the enclosure, but that finally did the trick. I tried a slew of speeds and temps and got bad results every time until the fan. Will have to crack one of the last cubes open and check bonding tomorrow. It finally matches the PETG and PLA cubes I already had though (Black and Blue ones). I even switched to just plain red ABS for a bit to make sure it wasn't just a bad roll.

Final settings that worked well are:

S3D
.2 layers
100% 1st layer
.4 mm extrusion width
.91 extrusion mult (steps have been calibrated and saved to eeprom)
\Coast/Wipe disabled
.4mm retraction, 40mm/s retract speed
50% 1st layer speed
3 tops/bottoms/shells
30% Honeycomb infill
90C Bed
245C Hotend
40% fan after layer 5
80 mm/s print speed, 80% underspeed for outlines, no min layer time

Reprinting with Linear Advance again now, had it turned off just in case it was causing the issues, but otherwise look good finally!

Re: eSun ABS+ problems with .2 layers

Holy smokes!! Dedication!!!

(I generally use a VERY small print for getting my extrusion multiplier setup, and I had like 50+ of them laying around, before my wife tossed them all(actually, don't tell her, but that was only the recent ones). I need to modify it slightly so I can do something crazy, like, build a giant chain or something with them, and prevent her from throwing them away again....) I generally print 2-4 of them EVERY time I change filament. (2 when everything works right, 4 when it don't the first time. I've got the math down, and I almost get it right after the first "tweak" every time now)

It makes sense that ABS would have this issue in a heated environment. I am going to order my first roll of ABS this weekend, if all goes to plan! But if I saw that I would have assumed hot-end temp is too high. It appears the filament is staying molten too long, and "shrinking/pulling" after extruding. Turning the fan on makes a LOT of sense, however I would think that might decrease your layer adhesion?
Did you ever try to cool down the hot-end?

Re: eSun ABS+ problems with .2 layers

Turning the fan on makes a LOT of sense, however I would think that might decrease your layer adhesion?
Did you ever try to cool down the hot-end?

I put a no-fan print and one of the final with fan prints into a vice and crushed them to see what layer adhesion was like, and there was no real difference. They were both pretty hard to crush in general, and once cracked open neither was easy to pry apart more, so didn't seem to matter.

I kept trying lower temps, reduced print speeds, min layer times, and even printing doubles to give it more time to cool. The magic setup was actually a faster print speed, less outer layer reduction, and some fan.

It almost seems like on a smaller print like this the nozzle temp can overcook things around it if lingering too long? The one thing I noticed watching the infill is that with the fan it didn't curl up at all, but with no fan there would be a bunch of curled up spots each layer that got knocked down on the next one.

Re: eSun ABS+ problems with .2 layers

Yeah, that sounds like the plastic isn't cooling fast enough. (Or as I was thinking, could be simply too hot, which you ruled out)

I haven't printed ABS yet, and I have never tried (and don't plan on) an enclosure.

But Yeah, that's a "not cooling fast enough, and "pulling".

The best analogy I can think of is a Prince Rupert drop.
If the glass cools slowly, the glass will ooze, and change shape, however it will not be "loaded". A Price Rupert drop, is quenched in water while it's molten, instantly cooling the outside of the glass, preventing it from changing shape ever again, so as the glass cools, and "shrinks" it puts extreme amounts of pressure on the glass. If you were to attempt to "chip" the price rupert drop, it will *explode* releasing all the energy in it. The relevance of this is, the plastics shrink.

ABS shrinks around 2% (reading around, this isn't from experience, or specifically Esun ABS+) This might not sound like a huge amount, but say you are printing a star, with each straight "line" being 10mm. That means that as the "top-most printed layer" cools, it will contract .2mm. Might not sound like much, but rather than pulling "straight" if the lower layers are still soft, it will "pull" the corner up. (especially bad on over-hangs) And .2mm is a HUGE Z axis variation. And that is possible from each layer. So in a matter of 5 layers, you could actually see (in theory, not very likely in application) .5mm of curling! (and this is easily enough to, depending on how the nozzle hits it, to "crash" the extruder, pop the part off the bed, or any of the many many many issues that stems from bumping the parts hard)

My thoughts:
1. MOAR FAN!
2. Put a fan in your enclosure to circulate the air more, blow it on the part possibly.
3. Put an exhaust/intake fan in the enclosure to reduce the temp inside it.
4. Have you tried E-SUN PLA PRO / E-SUN PLA+? I've replaced a handful of parts on my Mk3 with it, and they are holding up wonderfully. It's my favorite filament I've printed with so far. It's nothing like any of my other PLA's. Even the Prusa Grey filament, reminds me more of my 10$/spool el'cheapo PLA, than the E-SUN PLA PRO. It's softer. (Not much, but it's softer) It's VASTLY more flexible. You can tie the filament in TIGHT knots, without it breaking. (Yes, it deforms and don't go back, but regular PLA would have "snapped" long before) And I find it has comparable print quality to the more premium PLAs.