Hi!
I have problems with printing, using ABS.
It seems like the first layers srinks in a way, making the filament loose grip om the build tak.
I have tried to clean the buildtak, but it made no difference.
I’m using the standard temperatures and original, white Vellemann filament.
Sombody who have fixed this??
Could you post a picture.
My first guess would be that you Z axis is not calibrated.
Don’t believe that. It works fine with PLA.
BTW. I don’t know how I put in pictures.
It looks like this when I try; , only code.
Any info?
Put your picture in Dropbox, create a link and put that between Img-code. Than change the part www.dropbox.com… in the link to dl.dropbox.com…
About the ABS: I struggled also to get my first layers glued to the bed. Finally I bought an aerosol 3Dlac bed adhesive this week and I am happy. Use it on the glass side of the bed. After printing clean the glass with water. For the first time I made straight and perfect prints with ABS.
And maybe you have to play a little with the filament flow and the distance between nozzle and bed.
good luck
Without a heated bed (and even with) it’s very hard to print objects in ABS.
You can find a few guidelines in the [color=#408040]Wiki[/color].
The bed-nozzle distance must not be higher than 0.2mm.
Don’t print with temperatures above 225° with 75-80% flow (vary with color and brand of the filament).
A wide brim is mandatory.
Keep the infill low (25%). The more infill the more warping you’ll get.
Forget printing objects higher than 2 cm with the Buildtak, they will warp.
Once you get ABS obkects sticking to the Buildtak they’re almost impossible to remove.
Excuse, I presumed you had a heatbed.
I use heated bed, and i use ABS resolved in acetone to glue it to the bed.
I print it at 235 -240 degree and the cooling fan nearly at zero,
to ensure that the layers is melted together.
The fan to cool hot-end at min. 25%.
Heated bed is necessary at larger objekts
you can look at the link “unwanted retraction” to see some of my pictures where you can see some
of an ABS print at the second last of the pictures
It works superb now 
good luck
Jan