That probably has more to do with the model, it's the T-Rex jaw right? Without support the outer layers tend to curl up a bit and touch the nozzle. Because of the round tip on the nozzle the Zortrax has a bit more trouble with overhang so that's where you''ll see the dark spots. I think more support structure would help. And maybe higher fan speed, the ABS cools faster so will curl up less.
I watched as the teeth on the t rex skull were printed last night.
I changed the fan to 80%, and this didn't make any difference.
The teeth really came out bad, as 3DWP said, the abs curled up at the thin overhangsĀ and the nozzle contacted the abs on next passes.
At one point, the clashing was getting so bad, I though the model was going to be knocked off the raft!
Any solutions to this? I feel as if I have been sold a dud machine due to the problems I have had (faulty cable, lcd replacement, unfinished prints, bad scraper, burning etc)
You may be right about the free roll of ABS Caesar.