Vinyl Cutting Algorithms

I've added drag-knife vinyl cutting capability to my CNC Toolkit,
however it encounters a problem when the blade direction makes a
complete about turn of, or near to 180 degrees as often the drag
blade wont turn by itself and ends up going backwards for a while,
ruining the cut.
I'm considering various approaches to add an extra movement to help
the blade turn into the cut, just wondering if this is something
anyone else has come across before ?

thanks,

Rab
http://groups.yahoo.com/group/CNC_Toolkit/