Ball bearing improved version

After I failed twice to print a ball bearing model downloaded from Prusa 3D model online, I adjusted the Z value to -1.50mm by live Z value setting and reduced printing speed to 50%. Even I used 0.15 mm layer height, the balls inside the bearing were still slightly sticked to the outer and inner shells after printing. Also, you will find one side of the ball is not perfectly round due to a small support is needed  in order to print all the balls on a metal smooth plate. It is better to use a scalpel for removing this small support on each ball surface carefully without damaging the ball.  I used a plastic O-ring picker to move the balls carefully to separate them from the inner and outer shells.   Now, you should be able to rotate the ball bearing.