I have a Smoothieboard and I'm having a heck of a time getting the size of my prints to be correct. The prints are printing at about 90% their actual size.
I have played with the stepper settings for steps/mm. If I set the steps/mm to 88, I will get correct x/y dimensions, however any circles print in a somewhat oval shape. If I dial the steps back to 80, circles are fine but dimensionally the piece is incorrect. I have resorted to scaling in Slic3r, but that to me seems like a kludge. There is a GCODE command (G51) that will apply scaling, but that does not work in RepRap. Is there some sort of scaling or tuning that can be done with Smoothieboard that could compensate for this?
I'm printing with a QUBD TwoUp Cartesian printer. The controller that comes with the printer is a geeetech printrboard clone. It died and that's why I decided to try a Smoothieboard.
Below is a result of setting each stepper to 88 steps/mm. Note the shape of the circles. The rectangular perimeter is spot on dimensionally.
(I have a link that shows the image, but I am not allowed to post)