What is this called and how can I fix it?

[Venecha]

Greetings! I was printing a folding cube, but keep getting this on the surface. I am not sure what the problem is called, though. The surface isn't really smooth, but it doesn't look like infill? The hinges end up breaking on one side when folding it. I'm not sure how to clarify, but will definitely try if needed! This is PLA and am printing at 185c with the bed at 50c.

Please let me know if this should go in a different topic.

Thanks!
Venecha

[U.S. Water Rockets]

It looks like possibly the temperature of the nozzle is too high for the area printing on the upper layers. The bottom layers look like they have more area and this takes longer to print, so the layer cools off a lot by the time the layer above is started. As you climb this model, it looks like the sides taper, meaning less area to print per layer and therefore less time per layer. So one layer is put down and the next one comes on top of the last before it cools and so it squishes like toothpaste and looks runny.

You can solve a number of ways:

Reduce extruder temp.
Print another object beside this one so the time between layers is extended.
Use a layer fan.

Sometimes you find that a model varies so much that when you adjust for sparse layers that the dense layers suffer quality. In cases like this sometimes all you need to do is adjust the temperature lower manually with the knob on the front of the printer to a lower extruder temperature when the printer is printing sparse or dense layers.

[Venecha]

This is actually the inside. A picture of the cube before removing and unfolding it is below. The outside looks great. I was trying to print this http://www.thingiverse.com/thing:929504 . We are still trying to fine tune the setttings for PLA, and it seems really fiddly sometimes! Could it still be too high of an extruder temp?

Thanks for any and all help!

[Xenocrates]

That's likely insufficient cooling for that sort of overhang/bridging, and a lack of support.

[U.S. Water Rockets]

Ah!

Knowing that the print looks decent on the outside makes me think that perhaps the failed areas are where there are overhangs in the interior? If you could show the orientation of the part on the build plate it might be easier to diagnose. In the original image, you have broken it apart and removed the brim, so I don't know which way is "up" on any of those failed pieces. I just assumed they were all facing "up" in the image.

[Venecha]

Hmm...I may try and reprint it since i can't put it back together so that it makes sense. The odd looking bits were where it touched in the middle. There really isn't an overhang as such that I can tell. When reprint, I'll open it just a bit so you can see. The wonkiness is the horizontal plane where the top touches the bottom slightly. I suspect that if it is indeed too hot, then it is sticking together when there should possibly be a slight gap.

I'll also lower the temp on the reprint.

[Xenocrates]

It's that without support, that is an overhang/bridge, as one is not actually at the proper height to fuse with the other (which is good), and so some of the strands will drop and droop