I have a very cheap chinese engraver using belt drive for movement.
When engraving a picture line by line, I can only see it working bidirectional. This goes fast but is a problem with cheap machines.
The driving belts have a kind of slippage when changing from one to the opposite direction. This shifts the lines a bit and produce a kind of "interleave" image.
Is there a possibility to drive the lines unidirectional and then move back using a higher speed?
This would cost time but increase picture quality, specially when doing small sizes.
Another solution could be to add a slippage correction value which is added to even or odd lines in bidirectional mode, so you can "shift" them to match.