Inside the Z-axis tower is a long-threaded metal rail called the Z-slide. This rail is attached to a motor and moves inside the printer. The Z-slide needs to be greased annually using white lithium grease. This keeps the Z-slide free of dust and debris and allows it to operate smoothly.
 

To grease the Z-Slide of the printer:

1. Add a small amount of lithium grease to the tip of a clean Q-Tip.
2. Apply the grease by moving the Q-Tip starting near the top of the screw, moving down slowly.