glocom

Hello everybody, After printing several batch prints, my UM2 printer starts to print weird. I'm trying to print 4 small hooks so you can hang frames to a wall. The first one is printed normally, but the second one misses the outer shell. The third and fourth one are completely messed up. How can this happen? My Cura settings: Layer height: 0.1 mm Shell thickness: 0.8 mm Bottom / Top thickness: 0.6 mm Fill Density: 80% Print speed: 30 mm/s Initial layer thickness: 0.3 mm Initial layer line width: 100% Travel speed: 150 mm/s Bottom layer speed: 20 mm/s All the other speeds: 0 mm/s Thank you for your help