I have an ultimaker 2 that I have upgraded to a 2+ with the ultimaker nozzle upgrade kit. I have been printing on this for some time before the upgrade and about 25- 30 prints after the upgrade. I hate to go into ABS discussions again, but I just am not sure what to expect when I do print ABS as far as layer bonding. I have a spool of Ultimaker grey ABS that I can get absolutely beautiful prints from. However these parts need to be functional. When I test these to see how strong they are, they always fail my test.
Here is what I typically do. I take 2 pairs of needle nose pliers and then give the parts a tug trying to see if they will separate. It takes a little force, but they still break apart in the layers at a point that I would say is really not good. I have no idea how much force I am appying, but it is certainly not more than an amount that would make the part useable. I use a plexiglass sheet that I place across the front of my machine as a door. I have been tinkering with the temps and considering a heat lamp aimed through the top to increase my internal temperature, but the big question is how strong of a part can I expect to achieve?? Is there just always going to be some weak layer bonding issues with ABS. The sample I am trying to print is a cylinder with 2.5 mm walls and solid fill. The diameter is around 30 mm.
I think my last print was about 245C with no fans and 30mm/s speed and 80C buildplate. I checked my heater block with the nozzle off at the internal heating portion and it seems ot be about 8-10 C lower than the machine says.