When I started using the SMT50 to place my first board, I didn't really have component rotation setup properly in the Eagle source files. To get it working I just messed with the Part rotation in the PCB on the SMT50 until it was placed correctly. Not really the way to go, but at the time it was one less thing for me to sort out properly.

I finally had chance to look at rotation properly today (I know ... it's been a while) and things are not as helpful as you might hope. There are three sources of rotation information which might be used when picking and placing a part. The first is the location of the tape; either in the north feeder or the west feeder. These feeders are at 90 degrees to each other, so tapes loaded in different feeders start with different initial rotations. Next, each feeder has the ability to set its own rotation as part of the feeder configuration. And finally, the parts themselves also have rotations which may be set.

After some experimenting I was rather surprised to discover that the only rotation that matters is the one set on the part itself. The position of the feeder is ignored, as is the rotation set on the feeder. This means that, after you load your pick and place file into the machine, you need to very carefully check every rotation of every part because which tape the part is fetched from is not taken into account when rotating.

Oh, and don't forget; the PCB itself can also be rotated depending on how you load it into the machine which will also effect the value you set on the part rotation.

One final detail. Rotations are anticlockwise looking from above.