1y ago

Issues with layer adhesion (i think)

I'm a beginner 3D printing novice. I have done about 5-6 successful prints so far, and my last two have technically come out fine, but they seem very brittle. By brittle, i mean that both prints have snapped cleanly into several pieces, not by design. My extremely novice research has led me to think it's a layer adhesion issue - it is very cold here where I am right now, and I print in a non-climate controlled shed because of reasons. I do have an enclosure though, so i tried printing my PLA at 205 instead of 200, but same result. Is there a better way to correct prints snapping apart like that? I don't feel like i used any excessive force.

Ender 3 Pro Polymaker dual matte white/black PLA 1.75mm

19 comments

Is your filament wet? Wet filament tends to be brittle.
Post pics of your first layer and final print.
- I don't think it was wet, it's super dry in winter here, and i only bought it a week ago. As best i can see from the troubleshooting i did, i wasn't letting the enclosure internal temperature get high enough before starting the print.

it could be a few things... to start off with, what's the ambient temperature inside the enclosure? how cold is 'cold'?
Regardless, first step is probably to print a temperature calibration tower. (Most PLA I've used prints much more happily at 215-225,) I like this version of it. there's ways to set up the slicer to change the temperature at a given height. (For prusa, in the sliced preview pain, you can right click, it's the same menu as 'color change' and stuff. Start high and work low, going about five or ten degrees at a time.)
If the tower comes out no different and still brittle/poor adhesion across the full range... then my first thought is thermal stress building up in the part. if your enclosure is still too gold, consider piling on some more insulation (a generic quilt or blanket over, or stapled around inside will do nicely. Cotton quilts also have the advantage of being difficult to set on fire/melt.)
you say the part is brittle- does it snap opposite layer lines? or along layers? if it breaks in directions not aligned with the layer lines as easily as it does aligned, then it's probably not layer issues... at that point you have some sort of material issue. I'd suggest drying your filament out, and doing what you can to minimize the temperature changes during printing.
- How cold is cold?
  The printer says the hot end and bed are both ambient at 10C , which is 50F. For reference, it's 21F outside right now.
  Also, here is a picture of where it broke. The other print was similar. The crack can be seen on the left side of the pic.
  Also, I think my nozzle is clogged now, all of a sudden my first layers have gone to garbage. Compounding failures lol
  
  the printer says the hot end and bed are both ambient at 10C
  Try leaving the hot end at ambient, turning on the heat bed to it's printing temperature. Give it a while for everything to come up inside. considering room temp is around 20-22c or 68-73 F, it's not quite as bad as i feared, but it could be better.
  The heat bed should be able to warm it up a bit, but that is a very sharp differential, and drafts will cause problems. One thing to maybe try, is printing a tall brim. (basically a single-wall perimeter close to the part. They're not as useful if you have an enclosure, but they can help shield a draft and keep some of the heat in from the bed better.)
  Clogging could have happened if you're trying to print too low in temperature, which, given the layer problems, that also looks likely. there's a few variations, but you can try a cold pull to clear the nozzle (especially if it's only partially clogged.)
  
  What have your first layers looked like before this? The hard to remove skirt on prior prints is usually from your nozel being too close to your bed.