The vibrating hopper method can be used for smaller workpieces. Sliding rail method is better for medium-sized workpieces, and large-sized workpieces are driven by belt.

The repulsion mechanism can be a groove step at the lower part and a force-adjusting spring piece at the upper part, and the workpiece with downward plane is blocked by the groove and cannot slide out of the groove. The workpiece with the spherical surface facing downwards is pushed out of the groove by the force adjusting spring piece. When the center of gravity of the workpiece moves out of the groove, the workpiece slides out of the groove by gravity and enters the cycle again.