Simplify3D User Forum

I am trying to print an object with 1mm thick walls. after half a dozen prints that didn't fit, I realized that the walls are coming out too thick, @ 1.3 and 1.4 mm. What should I be looking at to control wall thickness. it's a standard MakerGear M2 with a 0.35mm nozzle diameter, 0.9 extrusion multiplier and extrusion width set to 0.4 mm

You might want to try using a manual extrusion width of 0.5mm. That way the perimeters will perfectly add up to form the 1mm wall. You can also look at the horizontal size compensation option on the Other tab if this happens with others parts as well (search the forum, there's lots of info about that one)