Issues with PLA layer adhesion

HI All, new here. Relatively new to 3d printing as well.

I'm using a creality CR10 v2 with BLTouch, a Titan extruder and it's all inside it's own enclosure.

I'm having trouble printing in PLA. Mostly with layer adhesion. Once a print is done, I remove it from the print bed and the layers seem very fragile. If I side load a layer at all, the part usually just crumbles (well, the layer fails).

I've tried bed temps, nozzle temps, fan speeds and layer heights. Nothing seems to make a difference. I've also played around with nozzle sizes and I seem to get a little better adhesion with smaller nozzles, but printing at a 0.2 takes forever!

I'm kind of at a loss of what to try next.

The really odd thing is I can print in ABS and everything comes out pretty much perfect and the parts are strong. I find that odd because it seems most people have troubles with ABS and not with PLA.

Suggestions on what to look at next?

Thanks.

what brand of pla are you using and what temps and speeds are you using ?

Got to admit pla layer adhesion is not something i've ever really had issues with.

Under extrusion would be the only thing that comes to mind.

what slicer are you using ?
And what is your extrusion ratio and extruded bead size set to ?

The extruded size is NOT the same as the nozzle size.
And - in my experience - slicers have a tendency to massively overestimate the extruded width.
On a 0.4 mm nozzle most slicers want to set the extrusion width to around 0.5.
I've measuired my extrusions widths and use those settings.
My delta with the 0.5mm nozzle runs at 0.52 and the other printers with 0.4mm nozzles are both currently set at 0.4

So that's worth checking.

If you don't yet have aet of digital calipers - get one :-)

Abs expandsa lot more than pla - so the extrusion width is always going to be larger, which might account for why abs works better than pla.

Quote:

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Originally Posted by curious aardvark

what brand of pla are you using and what temps and speeds are you using ? Got to admit pla layer adhesion is not something i've ever really had issues with. Under extrusion would be the only thing that comes to mind. what slicer are you using ? And what is your extrusion ratio and extruded bead size set to ? The extruded size is NOT the same as the nozzle size. And - in my experience - slicers have a tendency to massively overestimate the extruded width. On a 0.4 mm nozzle most slicers want to set the extrusion width to around 0.5. I've measuired my extrusions widths and use those settings. My delta with the 0.5mm nozzle runs at 0.52 and the other printers with 0.4mm nozzles are both currently set at 0.4 So that's worth checking. If you don't yet have aet of digital calipers - get one :-) Abs expandsa lot more than pla - so the extrusion width is always going to be larger, which might account for why abs works better than pla.

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Like I mentioned, I'm fairly new at this but I'll do my best to answer:

Brand pla: various, but mostly a brand named "printox".

Temps: varies. But mostly following the pla recommendation on the spool. I have tried also print 5-10 C over the recommended settings with little improvement, if any.

Speed: I'm guessing that's nozzle travel? Generally, I follow the recommended settings in the slicer program. I think it's 100% IIRC.

Slicer: Cura 4.8.0 Ratio, not sure what that is.

Bead size: I assume that's the layer height? if yes, I generally set layer height roughly 50-75% of the nozzle size with some variation up/down around those percentages.

Digital calipers: one of my other hobbies is machinist, so I've got measuring tools pretty much covered.

Here's a pic of my current printer and enclosure:

https://i17.servimg.com/u/f17/19/98/07/74/fr_44713.jpg
Thrown together with some leftover scraps. That's why the plexi has holes in it. Plexi is expensive these days of covid!

What it mostly does is just make it a little easier to keep the temps stable as well as keep drafts off it while printing.

Cheers

Edit: not sure why the forum keeps bunching up my sentences into one long paragraph. Tried to fix it, but it keeps getting smooshed into one block. Apologies to anyone having trouble reading it.

I think I might have solved my issues. I changed my infill settings and it seems the prints are much more durable than before. Perhaps the PLA just needed more "reinforcing" than the ABS....

okay - first thing.
You NEED to know what the slicer settings actually are.

100% means, literally, nothing unless you know what it'sa 100% of.

Cura is pretty awful.

Try prusaslicer, a lot more user friendly and much easier to see what the actul settings are.
https://www.prusa3d.com/prusaslicer/

If you don't know what the speed settings are - how can you work out what needs changing ?

As a rule of thumb. Never use 'standard' settings, always go into the 'advanced' (what should be standard) where it shows you actual relevant numbers.

The thing about the current state of 3dprinting is that it's NOT plug and play, so 'idiot menus' are almost totally useless as each brand of filament is different and within each brand the individual colours can behave quite differently as well.

So in order to adjust quickly, it really helps if you have an idea what settings you use and what you can change to adapt to different types of filament.

percentages are fine - if you know what it's a percentage of :-)
if 100% speed is 100mm/s - then its really easy to work out.
But if you don't know - then it's completely meaningless.

get prusaslicer and read or watch the tutorials.
I've still got a few issues with it, but unless you're prepared to pay for simplify3d, prusaslicer is about as good as it gets for free :
And as you've got a creality printer, I'm guessing you're not prepared to shell out much money to improve your 3d prints.
The slicer is the single most important part of the 3dprinting chain.
design - slice - print
The printer is a really simple creature that follows simple commands.
The slicer is a remarkable piece of software that translates a truly complex 3d cad model into really simple commands a dumb machine can follow.

To me the money spent on simplify3d was probably the best money I ever spent on any 3d printing related purchase.
And i don't like parting with money for software.
Or anything else for that matter :-)

With a printbite bed for my delta and original creator being, the second best value for money buy purchases.


https://www.prusa3d.com/prusaslicer/