Electronic – What initial orientation do pick&place machines use when applying the “rotation angle”


PCB assemblers require a file describing the component identifiers, the X and Y coordinates of the centre, and the rotation angle. I generate that file automatically from my CAD package (DesignSpark PCB). However the rotation angle that is generated is based on the footprint in the library. When the pick & place machine rotates the component based on the "rotation angle" specified, if it assumes a different footprint for angle=0°, then the component is going to end up the wrong way around.

Therefore, how can I be sure my CAD library and the pick & place database have the same assumption about the components orientations? I can only see one solution, which is to use the datasheet footprint figure (or pinout if not possible) as the initial orientation, but I would like confirmation and perhaps more details about how this works. Also, what happens then for passive components?

I looked around on the web and didn't find a standard, which is odd as in particular, both the designer and the assembler should agree on clockwise or anti-clockwise definition of the angle, even if I assume it is anticlockwise.

Best Answer

So each part that has a JEDEC standard such as an SOIC8 has the rotation angle defined. Although most fab houses will verify stuff with you.