First & second layer prints well. Layers after don't print at all
Hello all, I am not sure what is happening here. When I print these models, the first layer comes out great. There aren't any issues that would make you question it. Afterwards, sometimes on the second but mainly the third, it would get spotty/speckled and not flow out of the nozzle. After tryingg to unload the filament it would usually get stuck in the PTFE tube with a tiny clog there.
After clearing the clog and reinserting the filament (along with a purge) the machine is ready to print again only for this process to repeat again. Anybody have any suggestions on what is causing this?
RE: First & second layer prints well. Layers after don't print at all
I haven't a complete answer, but if the first and second layers are printing fine, and then it's downhill after that....
I would suggest that the issue is temperature related. As you get higher up the model, the bed temperature has progressively less effect on the model. Although I would expect the bed temperature still to be a significant factor on the third layer.
RE: First & second layer prints well. Layers after don't print at all
That is underextrusion cause by a partial clog somewhere. The first layer may print well because it prints slower, and the melted filament can manage to go through the partial clog at that speed. But as soon as you increase the speed on the second and successive layers (and thus the volumetric flow) the hotend is incapable of delivering enough melted plastic.
Honestly, I've had this problem several times with my MINI. The culprits may be:
(not in order of importance)
- - Clogged nozzle, try cold pull or nozzle replacement.
- - Damaged hotend PTFE tube, replace by a new one from Prusa store.
- - Worn out Bowden tube, replace by a new one from Prusa store.
More than one of those things can be happening at the same time. The Bowden tube should last, at least 500 hours of print time according to my experience (I replaced two of them in 1800h)
What got me by surprise last time and I had a hard time figuring it out was that some filament had carbonized on the inside of the heater block, in the thread where both the nozzle and the heat break get inserted. This was causing me to leave a gap between them even when using tools and a lot of force to screw them together.
Make sure your nozzle can be screwed completely by hand on the heater block, take it out, and make sure the heat break can be screwed completely in the heater block by hand. If anyone of them (in my case, both of them) get "stuck" before reaching the end of their thread, you may have carbonized filament on the heater block thread.
RE: First & second layer prints well. Layers after don't print at all
This might be just too low temperature for given filament to print that fast. The first layer may be slow and hot so it sticks to bed, the next layer gets hot enough from bed and the nozzle and is not having cooling so it has time to melt. Further if the cooling fan kicks in the temperature may be just too low to melt it for given extrusion speed.
Go to the PrusaSlicer to the sliced model view and see the temperatures and cooling per layer. See the difference in first two layers and higher. Also see bed temperature for first layer and consecutive layer.
Double check your temperatures are correct for given filament type. You can also need to just bump it right now with extra 10C to see if it helps quickly. Also worth to print temperature tower to see how filament behaves based on the temperature.
See my GitHub and printables.com for some 3d stuff that you may like.
Looks like a partial clog.
https://help.prusa3d.com/article/cold-pull-mini_126399
and read @joancasasvidal above.
Cheerio,