Final layers being flattened (UM3)

[dprometheus 0]

I am having issues with my UM3 where the final layers of a model are being flattened, distorting the final print. The print looks really good up the first few layers, and then the outer wall layers have large flattened circles, presumably from the extruder. I've manually leveled it multiple times, but it still seems to do this. The finer the layer height I use, the worse the effect seems to be.

 

Here's an image of a recent print, PLA + PVA for support with 0.04mm layer height.

* Combing is on all

* Retraction is enabled: enabled at at layer change, before outer wall

* Avoid printed parts and supports while traveling is enabled

* Z hop while retracted is enabled, only over printed parts

 

Any advice on how to prevent this?

[gr5 1,877]

This is a common problem when it's the very very last few layers but you have so many layers to go when doing the girl's face.  I would check that the fans are working.  And maybe lower the air temperature.  You want 100% fan with PLA.  Not the bottom layer but by the 5th layer the fans should be at 100% to cool the layer below before the next layer.

 

In addition I would print this "vertical" because you will get much better resolution on the girl's face if you print in the other orientation.

 

But if you print this vertical it looks like she has a pony tail printed last and that might have the same issue unless you also print a tower next to her for cooling purposes - when it prints the tower the model can cool for an extra 4 or so seconds (that's all it usually needs).

 

It's also possible the temperature is off on your core so you could try another AA 0.4 core.

 

But first and foremost check that the fan is working - what I see here is what I would expect if one or both of the 2 side fans were broken.

[Framar 25]

You can also increase this feature (minimum layer time)