Shifted circles and accuracy

Controllers Smoothie
1

I own a Kickstarter-Smoothie but limited time prevented me from experimenting with it until now.
It is driving a Shapeoko 2 system which previously run on an Ardunio-like controller.

But the conversion left me with two significant problems:

  1. Circles (pocket operation) always have the top half shifted a bit to the right. The shift get exponential bigger for bigger size circles.
  2. Accuracy. Honestly I don’t know the right term for it, but the dimensions are off. For example if I want a pocket operation, straight line, 5 units, the result is ~4,8 units long. A 10 unit long pocket is ~9,6 and a 15 unit long pocket ends up ~14,2 units long.
    The error gets bigger with on longer operations and is present on all axis…

Any ideas?

Imported from wikidot

2

Hey.

For issue 1, could we see a G-code that produces the error ( as short as possible ) ?

For issue 2, I think you need to tune your steps per millimiter, see : http://smoothieware.org/cnc-mill-guide#toc7

Cheers and sorry for taking so long to answer.