Surface Problems with UM2+ / 3dprimaABS

[neFri 0]

Hello everybody,

we got our um2+ one month ago and we are quite happy with the results we get with the factory pla.

Now we tried to switch to abs, as we need a bit more temperature resistance.

I know, that it takes quite some time to get abs to work, but i thought that i would share the experience and therby might be able to shorten the process a bit.

So here is the current state for a geometry that worked in pla very good:

parameters:

first layer: 0.27 mm

layer height: 0.1 mm

infill: 20%

wall thickness: 0.8 mm

top/bottom thickness: 0.8 mm

print speed: 60 mm/s

initial layer speed: 20 mm/s

cooling fans: off

adhesion type: raft

raft air-gap: 0.2 mm

initial layer z-overlap: 0.1 mm

raft top layers: 2

temp 230C

bed temp 100C

adhesion was fairly good on the glass, but surface kind of brakes

We also tried with glue, tape, increased bed tem,...

any ideas where to go next?

best regards

NeFri

[yvest 17]

So if I understand correctly it's essentially the first layer that is causing problems where it seems you have bad adhesion to the bed, right? I actually had that same issue with regular PLA where it turned out that I had to perform some proper bed leveling. If the nozzle is little too far from the bed, it will not stick well. Just a suggestion, I'm still learning myself :-)

[neFri 0]

We've had some adhesion problems in the past, but recently this seems to be solved by recalibrating the platform (+half a turn closer). The current problem is with the first layers after the raft (as can be seen in the 2nd pic). Here the surface is very bad, it seems like the surface has cracks that open.

Guess the learning will never end;-)