tonyno wrote:This is interesting. 1" cube, cut short, printed with no compensation. Check that taper on the lower 2.6mm!
Over extrusion could cause that if the cube is hollow with a solid floor. The floor of the cube, if over extruded, is going to bulge out more than the side walls because there's more plastic extruded there. I would look at lowering the extrusion multiplier first by a little bit.
Also, a heated build plate can cause this, especially if its too high, and you are very slightly over extruding.
On my FlashForge Dreamer I print ABS using 110 C for the first layer and then drop to 105 C. On the MakerBot Replicator 2X I start with 115 C and drop to 110 C.
If I don't drop the temperature on the second layer, I get this bulging problem for a few layers, especially if I'm very slightly over extruding.