Welcome to the SeeMeCNC Community

After the long calibration process I am moving towards actual printing.

Best bed adherent for me: Hairspray.

I tried lots of prints, starting with the default print settings from the manual
I aimed for the best results by trying bracketed ranges of these settings:
ABS Print temp 205-220 degrees
Bed around 65-75 degrees
Speed from 10mm/s to 80 mm/s
retraction from 0 to 10mm/s
lift from 0 to 3mm

Cooling fan blowing across bed.

Main issues:
Popping off bed halfway through print
causes seem to be:
cooling fan shrinkling the piece off the bed(cooling fan is needed otherwise I get blobs / sag
print head hits a raised blob even with lift and knocks piece sideways

Blobbing / nibbing
Seems to be related to cooling / maybe a flow issue?
Most blobbing is on one side - the lee - of the model away from the fan..
hotend mounted cooling fan badly needed.

Bad results on the sharp corners of anything square.
Each corner has it's own problems:
Top left = too rounded, prone to blobbing and over extrusion
Bot left = ok, a bit rounded
bot right = not too bad
top right = slight blobbing

It's getting there.
I am going to stop testing while I wait for all the "official" SeemeCNC fans to arrive from over the atlantic.
I can go no further with my the current fans that are ripped from old computers etc.

Have you calibrated your extruder so that when you request it to extrude 100mm that is exactly what it extrudes?
Your heatbed should be at least 90C for ABS and a cooling fan should not be necessary.
It appears from the prints you show that your extruder calibration is off a little.
See Polygonhell's excellent tutorial on extruder calibration at http://forum.seemecnc.com/viewtopic.php?f=54&t=1163

Yes - I have tried Polygonhell's calibration process.
I have left my nozzle size and extrusion multiplier untouched for now because:

On a solid test cube, I already get the right amount of infilll without changing the extrusion multiplier.
but only *On some temperature / speed combinations*
If I run slower / hotter / faster / colder - I get too much/little material, so I need to learn how
extrusion multipler settings can best be used

I guess It's something to tweak once I know some good all-round print temperatures and speeds.
I am currently leaning towards 210 to 215 degrees with ABS @ 20-30 mm/s

You sound as though you have a good handle on knowing what to tweak but I still don't understand the need for a cooling fan with ABS.

thanks - improving here, but a way to go..
The Owl is an example of how fans are improving my ABS prints
you can tell, looking at the owls face, which side has benefited from fan cooling
As soon as my mini fans arrive I will be trying a some hotend mounted ducted fans...

analog_banana wrote:ABS Print temp 205-220 degrees

Sounds low to me. I'm using 230-235 for pretty much all filament I have.

Bed around 65-75 degrees

That is way too low and probably a big reason for the edge lifting (along with another one below).

Cooling fan blowing across bed.

MAJORLY bad idea with ABS.
ABS does not need one and is definitely hurt by this. If you're seeing an improvement in build quality, there's something else wrong.

Blobbing / nibbing
Seems to be related to cooling / maybe a flow issue?

Extruder calibration fixed this largely for me.
Also setting a fixed extrusion width (if you use Slic3r). And make sure your nozzle isn't clogged.

Bad results on the sharp corners of anything square.
Each corner has it's own problems:
Top left = too rounded, prone to blobbing and over extrusion
Bot left = ok, a bit rounded
bot right = not too bad
top right = slight blobbing

Again, extruder calibration, fixed extrusion width and get rid of the fan....

This is my second try at Polygonhells's Extruder Calibration.
My measuremetns suggested 0.85 to 0.9 Extrusion Multiplier,
And the solid cube tests backed up that figure.

Based on the advice in this thread I am now printing at:
230 to 235 hotend
90 degrees Heated bed. (Really hard to maintain that high temp! It struggles!)
Retested the extruder - still accurately giving 100mm when asked
NO FAN used!

I think my extrusion width is OK, but the "Directional Artifacts" remain.
See the second photo for an example of each side of the cubes.
The left side of the print is always the worst.
In progress the head always seems to be nudging at the perimeters on the corners,
pulling the edges around as they are printing. especially on the back left.

Polygonhells guide says to turn off retraction, but even with retraction and lift on,
I am getting this nudging / head based deformations.

Maybe something to do with:
delta arms?
the belts?
the columns?
bed levelling?
Resonant Vibration?

Might move the machine on to the floor!

Tried the delta arm blues calibration process - not really sure if it printed correctly - but I *think*
my arms are ok!

I also printed a bed test - not sure if that worked correctly - it's quite patchy..