First few layers bad

[geddski]

My prints are all having the same issue: the first few layers are printing too small. Initially I thought it was printing right and then warping, but after watching it closely I realized it's simply printing wrong and then correcting after a while. What could be causing this?

Pics:

[ednisley]

the first few layers are printing too small

That means there's more space available for the plastic than the slicer expects: the platform is too far away during the first layer, so the plastic forms a narrow rod under the nozzle instead of a flattened rectangle.

The position isn't off by much, because those thin walls actually stuck to the platform!

Adjust the platform upward by 0.1 mm (about 1/6 turn of the Z adjusting bolt, which is easy) to reduce the nozzle-to-platform distance, print another thinwall cube, and iterate until all the layers have the same width. You can fine-tune with fractional turns and turn it the other way if you overshoot.

Slicers provide first-layer parameters that allow you to shoot yourself in the foot, but the physical adjustment will get you into the right ballpark for whatever your settings are right now. If you've tweaked the Z = 0 override, then you should probably reset it and adjust the physical position to make everything sensible.

Then you can measure the wall and tweak the Extrusion Multiplier, which is probably what you intended to do when you discovered the first-layer problem... [grin]