Reason for gaps in bottom layer/filament sticking to nozzle
So, this has been brought up before, but I'm interested in why it is happening. This print is in PETG, and what is happening is that the bottom shell infill is sticking to the nozzle rather than than the PETG already on the bed. On the problem layer(s) the filament seems to extrude unevenly (see photo above). Before I got to this point, this was also happening to a lesser extent on the first level. I "fixed" the problem by (in the following order): changing the nozzle, lowering the live z adjust, increasing the print temp to 240 °C, running the mesh leveling at 7x7 grid, slowing the print down to 75% of the original speed and pulling off some of the worst "accumulations," but it just mitigated the problem enough for subsequent layers to lay down well enough to bury the problem layer. On all the subsequent layers, the filament seams to be coming out of the nozzle consistently. However, going through the above work-around every time I want to print in PETG is pretty time-consuming, and therefore, unsustainable. Surely, someone here must have encountered this problem and found a fix for the issue? Looking for any constructive thoughts on the matter. Perhaps this post should be moved to another topic.
Update: the file printed satisfactorily for a prototype, but there are obviously issues. It might be of note that the printer heater block and nozzle has "blobbed" in the past and there is still some residual plastic on the heater block. Perhaps that is causing inconsistency in the nozzle temperature?
OK, think I found at least part of the problem. This must have happened when I switched nozzles (see attached image). It appears to be PETG leaking out of the top of the heating block. I'm going to pull the hot end apart and clean it. If anyone has any wisdom on this kind of issue, I'm all ears.