I created a set of widely spaced bullseye patterns to determine alignment offset on my pro unit. The original svg file was created on a 20"x12" work space and the outer four bullseyes were placed 2" from each edge. The bullseye pattern has 2", 1.5", 1" and 0.5" circles. An engraved cross in centered on each circle pattern. The right two targets were outside of the cutting area, so I moved them 0.25" to the left. In the image below, I manually move the set to the left a bit to be inside of the cutting work space outline by the hatched areas.
The engraving started at the lower right and proceded correctly until the horizontal arms of the cross was engraved and the first pass hit on the right side with a knock sound and caused the alignment to change, as seen in the after picture.
All of the engraved and scored lines have moved to the left.
I though that the design might be too close to the right side, so I moved the left two targets in the svg to the righ by 0.25".
I manually centered the design so there was more space on the right side.
(no before image available.)
The same shift occurred with more space between the design and the hatched area.
Below is a closeup of the lower right target with the first line of the engrave circled.
Presumably, if I move the outer targets towards the center, especially those on the right, then this positioning error will not happen. The question is how far to move the targets to the left?