PLA prints are too soft, too weak, breaking with hands

[Smurf2 0]

Hi guys.
Finally found a Forum which is active!!

 

My problem is that all my PLA prints are too soft, too weak, breaking with fingers, walls not good. See lights trough walls on 20%-40% infill, 

I have Ender 3 printer a long time. Started print with ABS, Devil Design, and I never had bigger issue with it.

 

But now I switch on PLA, 120/60 c, nozzle 0.4. And important thing is that my PLA filament have moisture - it cracking when bend it. I Using some enclosure too.

 

If you look first picture, left is ABS, perfect solid print with 20%. Hard. Can't break with hands. But on the right is my PLA print 20%. 120/60 C. Speed 70%, wall speed 30%. That is very bad print and you can see lights trough.

 

I fully cleaned printer and change extruder wheel. It's same. Then I
put PLA filament on radiator to dry about 12 hours, and in Cura adjust E-step. Also enabled retraction (distance=6, speed=25).

After that print is better (second picture) but not enough. Stringing disappear. Model little bit harder, but again week and soft, cracking when you touch with fingers on 20% infill. Walls bad.

 

The both ABS and PLA model are printed with same spec, so think that 20% must be harder. It looks like infill empty inside, but is not.

 

Today I tried with white PLA on 40% infill, which is opened only once! Same thing!

 

So guys, I am crazy from that! Is that all because moisture of filament or bad brand?? I am ready to back on ABS if I not repair PLA print!
Think I have two spare brands of ABS, but only this one of PLA. Do I need to buy other brand PLA? Think that Devil Design must work. Change Extruder?

Edited March 26, 2023 by Smurf2

[aabfm 0]

Quick question(s): are you using a nozzle temp of 120oC? Is this according to the recommended temp range of the filament you're using?

[Dustin 129]

yea... 120c is super cold.. if your printing pla at 120c, you have hardware issues on that machine... which you would need to reach out to the Creality community directly for help on.

[dsp 18]

for what I can see you have underextrusion raising the temperature usually helps i print my pla at 200°C 

and a print speed of 70% how fast is 100%? try fiddling with the settings but even with bad pla a better printing quality should be doable.

 

 

[GregValiant 1,246]

I'm surprised it will extrude at all at 120°C.  The default "Cold Extrusion Prevention" temperature (M302) should be about 170° in the firmware.

[Smurf2 0]

On 3/28/2023 at 4:59 PM, aabfm said:

Quick question(s): are you using a nozzle temp of 120oC? Is this according to the recommended temp range of the filament you're using?

Guys I am very sorry. It is quick mistake in typing.
I printed at 220C. 

Sorry for delay, not saw messages.

 

On 3/29/2023 at 11:54 AM, dsp said:

for what I can see you have underextrusion raising the temperature usually helps i print my pla at 200°C 

and a print speed of 70% how fast is 100%? 

I printed always on 70% in Cura, and on printer is only 100% for default. That is,always work for me and not think that is problem there.

 

This week I returned to ABS (230/90C) and look how beutifull print is.

 

Edited March 30, 2023 by Smurf2

[Smurf2 0]

On 3/29/2023 at 3:40 PM, GregValiant said:

I'm surprised it will extrude at all at 120°C.  The default "Cold Extrusion Prevention" temperature (M302) should be about 170° in the firmware.

Sorry 😞 😞

 

Strange thing is what I notice is that sometimes is it hard, and then quick change to soft print.

You see on first black pictures  on light, bottom is dark, and in middle start problem in current case (Post#1).

 

EDIT: This is today ABS print on 60%. It looks perfect print, but if you press it, you will hear a cracking. Maybe is that because thin walls.. Not sure that is been like that before.

 

Edited March 30, 2023 by Smurf2