SOLVED Small creases forming on first layer, unknown cause or resolution

[GoguyT3d 8]

I have an UM3S and am using Cura 4.8.0 I am attempting to print an imported file from Autodesk Fusion 360. I am using Generic CPE settings with a 3rd party filament. My only problem is that when the printer is printing the first layer a skip or studder or something of that nature happens along the same line across the skin of the first layer creating an imperfection or seam all the way across it when there should just be straight lines. I have included photos to show how the filament creates this seam when it should be printing a straight line all the way across. It does not heavily affect the print but I would like to know if anyone has seen this type of nature before or if there is a resolution to it. Picture one and two are from the under the bed looking up and picture three is from above the bed looking down with an arrow of where the crease starts. I am guessing this is in relation to the slicer because that is what tells the printer to make these specific lines or possibly the printer but I hope not. I forgot to mention that I have attempted to move the print to a new location of the print bed to see if it had anything to do with auto leveling but it made the crease again in the exact same place as the first time. Any comments welcome

Upper_Crossbrace.3mf

Edited December 15, 2020 by GoguyT3d
Added 3mf

[GoguyT3d 8]

I have done over 21 different test prints consecutively changing only one factor at a time to see what changes were made to the print when putting down the first layer. Moving the print to a new location on the print bed didn't remove the problem, it just continued to crease in the same direction (in accordance with the bed) as the previous times. When flipping the glass build-plate over the creases were identical. The bed was always cleaned with soap and water and dried before each test. I then started to change settings such as initial layer flow, initial layer line width, initial layer height, nozzle temperature, and initial layer print speed, one at a time, which none of those settings made any change to the way the creases were occurring on every print, pointing in the same directions each time. I even went all the way back to where the file came from at Fusion 360 and imported the file again, although this time I selected under the "refinement" High quality instead of medium. I then used all the unmodified settings for the filament I was using and printed a test print first layer at .3mm initial layer height and it almost solved the problem though it seemed like the filament was too far from the bed (not good adhesion). If you are having this problem and are using Fusion 360 I recommend leaving any comments for assistance in solving this problem. I am still printing with the creases. Also FYI this isn't just my UM3S that it does this, it also happens with my Ender 3 Pro on large flat first layers that require alot of base skin. The picture included is the effect on my Ender 3 Pro

Edited February 20, 2021 by GoguyT3d
Change in results

[GoguyT3d 8]

**PROBLEM SOLVED**

OVEREXTRUSION

I just tried one more test print with the same object file from Autodesk Fusion 360 and used medium refinement to convert to Cura. Within Cura I used all the same settings for Generic CPE accept for the Initial Layer Flow. After analyzing the bottom of the prints and creases on them I noticed that it looked a lot like too much filament was flowing with nowhere to go but on top of itself (causing creases) so I lowered the Initial Layer Flow from 100% down to 75% and yielded these results shown in this picture with clear PETG. This is my first test with successful results although I think by the smooth surface of the bottom of the print and filled lines with no gaps that I hit it right on the nose.

[gr5 2,167]

So typically the bottom layer is leveled on purpose such that it will squish extra hard.  This is so you squish the bottom layer more which causes parts to stick better.  So lowering flow to 75% may result in your parts not sticking as well.