Ripple Where Part Meets Plate

[needsmorecoolant 0]

Hello everyone. I recently bought an Ultimaker 3 and started making inspection kits for work. I am printing in Tough PLA with the default Cura profile. I am getting ripples (left side of block) on the bottom of the print where it meets the glass. I see it along the X axis surface but not on the Y axis surface. I get the same ripples when skewing the part 5 degrees from parallel with the X axis. 

 

Machine firmware is current and Cura is updated to the latest version. I checked my short belts and they are tight, long belts maybe could be tighter but they are the same in X as they are in Y. Has anyone experienced this type of artifact? 

 

Edited November 28, 2018 by needsmorecoolant

[needsmorecoolant 0]

I don't know if this helps, but my machine is a refurbished UM3 from Matterhackers. Has anyone had good experience with refurbished printers from them?

[geert_2 560]

Maybe it could also be the infill that is shining through? If you have a thin outer shell, and temperature of the bed, or of printing, is rather hot, it might slightly deform and let the infill shine through? Similar to in big ships, you see the internal reinforcements shine through the hull. Just guessing though...

 

[needsmorecoolant 0]

One thing I have noticed is the ripple is always negative material, perhaps it has to do with the density of the infill, I was using 20% or 10% on this part.