iloveorangesoda

Hi I am new to 3D Printing and I am trying to print a photo frame I made in Tinkercad. I sliced it using prusa and have tried printing in on my prusa and my ender3 but I keep getting two lines in the print. I print it upright without supports at 210 bed 60. Infill is 20%. The lines seem to be appearing in line with the photo space? The photo frame is made from a solid rectangle shape with square hole cut out and a slit added for the photo. Thanks