When using older lasers, the beam spot is often not circular. Often the beam shape is elliptic and its shape is changing. If the beam shape is larger in X than in Y, then the cut slot (kerf) has different dimension when path is along X versus path is along Y. (imagine the slot made by an ellipse moving around an equilateral triangle.
It was found that traveling faster in the direction normal to the widest beam, caused the slot width to reduce. A consistant slot could be accomplished by varying velocity. The relationship of beam shape to path was understood, and hal components created to adjust velocity accordingly. If we must use those machine and make enough precise burning, we can create dynamic beam shape compensation module in hal. After that and few changes we can force EMC laser machine to make precise burning in each direction.