Slicer doesn't like the bearing wheels to much common walls between the bearing and wheel surfaces to get them to separate easily. Need to modify the model a bit. (edited)

Nice Design. Printed it with 50% size as the original was to big for what I had in mind. Actually struggling with the "Happy" part - still breaking when trying to unfold it for the first time. Might be of the resizing. The issue is that some letter holes are too near to the junctions. If I could suggest an improvement - if the letters would be more centered, it might not break that easy.