I need your help to understand what causes it and how to print successfully.
I’d like to print this: https://www.thingiverse.com/thing:2702654 but after about a few layers the print goes wrong, see the images. It seems like there were excess materials on the perimeter, which increas the height of the print and the head collapses on it of course. I assumed overextrusion, and reduced the extrusion multiplier down to 0.65 without no success unfortunately.
Small layer height 0.05-0.1 mm (I tried various layer height). REC ABS. 250C. E3DV6 direct extruder.
@Jeff_Ramble There is no support. That’s the problem at the edge what you see. 
The outer edge should be flat, leveled with the rest of the object. But it gets higher.
seems to hot from the looks of it - check that the thermistor touches the metal of the hotend if not use some thin teflon tube so it gets pressed against the metal or something that will withstand the heat
also check the connections of the thermistor they can loosen up when working on the hotend
if it was to hot i would also clean the nozzle to prevent cloging (thin metal wire is the best)
@Googolplex_Goku This is the new E3D hotend with the thermistor module. The hotend looks OK. For ABS I never use parts fan, maybe this should be an exception?
@Jeno_Bozoki have you bought the hotend afterwards to the printer maybe a wrong thermistor value in the fw maybe a cable break somewhere in between the thermistor and board or maybe the thermistor is faulty (i hope not)
i had some prints that looked similiar and where the result of printing to hot so thats why i think it has something todo with the temp
for part cooling - place a vent so that it blows over the print if the quality gets better than yeah it could be the missing part cooling
@Googolplex_Goku I’ll measure the temp with a thermocouple to check it.
You should also make sure that the part cooling fan doesn’t blow directly on the hotend thermistor. If it does, the thermistor reading will be way off.
@Linus_Nielsen currently there is no part fan at all.
Look like it is too hot.
ABS should have a fan mounted on the extruder. I think your bed is also too hot.
Also eliminate your infil so this model is solid.
Look on your filament manufacturers web site for the proper temperature settings.
@MidnightVisions If you mean a part cooling fan, then I totally disagree. I have no part cooling fan, and after I turned the fan for the hotend so that it not partly blew on the heatbed, I have perfect ABS prints. No curling and warping anymore.
Do other prints work ok? Almost looks like you are getting heat creep in your hot end that is clogging or slowing the extrusion as well as curling of the outer edges of the print.
There is a rounded edge on the underside so if the plastic is too hot below it can curl if the top layers cool too much. The shell should be 1.2mm thick at a minimum. Shouldn’t need to set the infill to more than 24%.
I used PLA for the print and a part cooling fan at 100% by 0.5mm in height.
@Jeff_Parish Yes, other prints are OK. As I’m using a direct extruder, and printing very thin layer, it means the extruder stepper is moving really slow. So the extrusion is really slow by default. It might be a slicer “error” as well. I’m using S3D. As you point out there is a rounded edge on the bottom. As I use 0.25 mm 1st layer height, the most outer perimeter of the 2nd layer seems to be hanging in the air. Now I’m testing with 0.15 1st layer height, and 0.6 mm manual layer width. According to S3D there is no perimeters hanging in the air.
Ah, if the extrusion rate is slowed down too much then you might have to drop the extrusion temperature a little (so it doesn’t transmit back up the extruder - slow speed induced heat creep) or speed up the print speed so long as you don’t trigger a skip.
For rounded edges on the bottom it is best to use thinner layers and a wide nozzle. More of the nozzle width is supported by the previous layers material when it approaches horizontal.
I suspect that most of these issues then are slicer parameters. I used 0.1mm on the first layer and 0.05mm on all the rest with a 0.4mm nozzle and a 1.2mm shell. Got beautiful results. With some filaments the surface is so smooth I could almost get away without polishing.
So to finish this journey. I did all the preparations (bed leveling, new Buildtak sheet, filament drying). I was able to print OK with 200C extruder temp and 80C bed temp with 70% part fan with REC ABS. The perimeter speed was 10 mm/s to allow more cooling. With this low temperature the bed adhesion didn’t work, even with the new Buildtak. I used raft to fix it. Because of this the bottom side required a bit more work with sand paper.
I attach the picture of the finished part and in progress states.
You have paved new ground with this project in ABS. Came out nice!