i've built a ton of printers

i run a large bank for a living and have done so for many years

thought i'd seen every problem you could see with a 3d printer......nope


just finished a new aurora i3 (my current favorites)


no matter what you slice every print turns out 20% smaller on the x and y than sliced

the z prints exactly as sliced, perfect


anybody got any ideas?

thanks in advance

not an expert but the first thing I would suspect is that the steps per mm is set up wrong or maybe one of the jumpers for the micro steps is loose.

I agree with Qdeathstar. Confirm steps per mm with the Prusa Calculator.

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Prusa i3 Rework - Ramps 1.4 - E3d Lite6 - Full Graphic LCD Controller

Number of teeth on the GT2 pulleys is 16 instead of 20. That's exactly 20% difference.
-Olaf

it was the pulleys

i didnt think i even had any 16 t pulleys

thanks for the help