One - those horizontal lines in the filament show that you have too much tension on your extruder and you are damaging the filament.
Two - You do not have enough cooling north of the heat break. Meaning the cooling fan on the heatsink that attaches to the hot block is not getting cooled enough. So when the filament enters this area, it expands from the heat.
If you have recently purchased an Ultimaker 3 printer, you may be wondering how to print multicolor layers on it. Fortunately, there are many new features to explore with the new Ultimaker 3 printer, and Cura has been designed to take full advantage of those features. Use one of our guides to help you get started with dual color prints. After downloading Cura, open a new project, and then follow the steps to load the materials and model files.
Cura is an open-source 3D printing software program that works with many types of 3D printers. The software is free and has many benefits, including automatic calibration and a range of pre-tested profiles for beginners. The software also allows dual printing, and supports a number of plugins that allow you to customize the user interface and print settings. For the most accurate and consistent results, Cura can handle multiple 3D printers with ease.
To print multicolor layers, choose your preferred extruder paths. Extruder paths can be different for each printer, but a general rule of thumb is to leave them at everywhere and compare them. Try different settings to see which one produces the best results. Remember to test each one by printing a test print with the different settings. Also, keep in mind that filament retraction speed can affect the printing of raised text.