Top Layer Issue

[CTotten 18]

I recently started having some issues where large, flat layers are very "bumpy" and "fuzzy".  I have A LOT of little balls of filament at the bottom of the printer, as well.

 

The first picture is the top layer of the last 2 units I have printed.  The second picture is the previous ones.  Any ideas?

 

The issues started after I had a bunch of issues all around the same time.  Front fan stopped working, so I fixed that.  Also replaced bowden tubes, cleaned the feeders (and checked tension), and replaced both print cores.

 

And this is not limited to the top layer.  I have seen this a lot of times over the years on the first layer, but it gets cleaner after every layer during the build, and never seen this on the top layers.

 

I feel like this is over-extruding, but I haven't been able to get this to stop.  I tried raising and lowering the extruder temp (+/- 5 degrees), tried reducing material flow (to 90%), and even tried slowing down the print speed (to 75%) all from the S5 touch screen during a print, with no noticable change.

 

These are "lab fixtures", so they do not need to be pretty, but it is pretty annoying to have this sudden drop in quality of the finished surfaces.

[CTotten 18]

After some additional work, I think this was an issue with the print file, although not sure what would cause that.  I switched over to printing the identical part in a different color, and that print is just fine.

 

Odd.  I printed 2 in red that came out as expected, had some issues with the machine that I had to fix, and also updated the print file to block support material in some areas that were not needed, then this started happening.

The new prints in a different color are also using support blocking, but not issue.

 

Oh, well.  Chalk another one up to gremlins, I guess.