Here you can see what we call a deposit. It happens during the last 1% of a print cycle when it switches colors and when it happens, an extra amount of heated ABS is extruded on the top of your model. You can remove these pretty easily, but doing so may affect the appearance of your print.
These lines on the side of your object, which we call zippers, will always be vertical. That’s because they occur at the transition point from one layer to the next. Sometimes they are a little rough, and sometimes smooth. Any small nodules can be removed, but again, doing so may affect the appearance of your print.
We’ve worked hard to minimize these artifacts and we’ll keep working on minimizing them. As a purchaser of an experimental printer, you’re on the adventure with us and we can’t wait to see what you’ll make. Please share all your thoughts and feedback (there’s been a ton already!) through our general feedback line, thoughts@makerbot.com. Also, when you share your models on Thingiverse, please use the tag “dualstrusion” so we can see what you’ve been up to!