Hi Sim,
It’s a bit tough to tell from the pictures, but the first alignment point seems a bit too low in the y-axis. If this is the case, the results you’re seeing make sense based on the algorithm.
The first point (which we call the pivot point) sets the absolute center of that feature in space - meaning that during the check, the printer will go right back to that same exact position you aligned to.
The second point (which we call the satellite point) is used to calculate the angle between the pivot and satellite. However, the V-One doesn’t do any scaling to your design (which is on purpose - we don’t want to be changing the size of IC pads), and so needs to preserve the relative distance between these features. If the pivot is not completely centered, the V-One will miss the satellite point, as you’re seeing.
In short, there are 4 possible causes:
- The pivot point wasn’t centered properly
- The satellite point wasn’t centered properly
- The gerber file you’re using is out of date or doesn’t correspond to the physical layout
- The V-One’s calibration has shifted due to improper handling
- The V-One was not calibrated properly in production
Each V-One is automatically calibrated with a camera and checked against a physical reference to ensure that the alignment is in spec before it goes out the door - while it’s not impossible that a unit could have slipped through somehow, it’s much more likely that it’s 1-4.
I’d suggest trying again using two different points on your board, and perhaps using a different board altogether to see if you get the same behaviour.
