Hello there,

I'm writing a macro which calculates the toolpath for an archimedean spiral. Some controls do have a G code for that others don't.

My idea is to divide the spiral into circular arcs. For each arc I have to calculate the end point located on the spiral's path. The start point is simply the end point of the former arc. Start and end point are connected by a circular arc.

The problem is to find the radius for each particular circular arc with the smallest possible deviation to the path of the perfect spiral.

Does somebody have a formular for that?

Thanks
Frank