Bulging on one corner of a print

Hi, I was wondering if anyone can offer help in diagnosing this problem. One corner of my prints shows "bulging" after the first few layers. The pictures show a 10mm cube printed at 0.1mm layer height. The problem is present in all of the cubes but is most clearly visible in the 4th one of the first picture. Most the print is very precise, but one corner is badly distorted. It is the corner where each layer starts, which I think could be significant, and its also on the opposite side from the cooling fan.

Some details: Eclips3D printing PLA at 40mm/s, 0.1mm layer height, 195C on a 50C bed with 15s minimum layer time, cooling fan at 50%, 30% infill. Reducing extrusion to 0.95 or temperature to 190 improves the situation but it doesn't go away. The printer has been doing fine with these settings for a while, so it's puzzling that it appeared now. (Another puzzle at the same time is that the hot end won't maintain its temperature with the fan at 100%, which it was again doing fine).

Any ideas welcome. It looks like the filament is too hot, but why this should appear now when I've used the same temperature for ages is a mystery. And if the filament was too hot, I'd also expect it to affect the rest of the object which as I noted is very precise.

Edited 1 time(s). Last edit at 06/16/2016 02:49PM by animoose.

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See my blog at [moosteria.blogspot.com].

Update: I suspect this is a Slic3r problem. See [forums.reprap.org].

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See my blog at [moosteria.blogspot.com].

> and its also on the opposite side from the cooling fan

did you already try printing multiple cubes,
I get this problem, when the object stays to warm, so add multiple cubes will give the previous layer to cool down

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P3steel DXL, with Due/RADDS/Raps128 dual Wade's extruder

A 10mm cube is very small, so the head will stay close to all of it, all of the time. The side where the layer change happens gets more radiant heat than the rest due to the pause between layers, plus the extra ooze during the vertical travel, and if it's also farthest from the fan then everything adds up against you. Things that might help would include insulating the heater block to reduce radiated heat, improving the cooling with either a more complex fan shroud or by adding a second fan on the opposite side, printing two or more cubes at a time with a large travel distance between (and/or a slowish travel speed), printing bigger cubes

Your comments about slic3r in the other thread are interesting. Slic3r has been fighting some fairly bad problems with too much extrusion under various circumstances. These seem to have been mostly fixed in the 1.3.0-dev stream, but unfortunately it has it's own problems that can lead to very slow print moves with negative extrusion rates. It doesn't seem to happen if you avoid using the autospeed settings, so you might want to give a new dev build a try.