From viewing the original model from the RIGHT shows that Point located at COG is not located at the axis of revolution. That will make a vibration while the part rotated around its axes of revolution These must be brought together to meet the design goal. After we did the optimization some dimension got changed the R changed from R1.35 to R.73 which is almost a half of the original one moreover to a small change in a shoulder which remain around 0.224; moreover to a small change of the angle from 40 deg to 44.36deg. these change in dimension makes the offset equal zero therefore the point of COG became align to the axis of rotation.