The upper lens is responsible for collimating and concentrating the laser beam into a small, precise spot on the material's surface. This focusing action is essential for achieving high-precision cuts and ensuring that the laser energy is efficiently utilized.

It's important to keep the upper lens clean and well-maintained because any dirt, debris, or damage to the lens can affect the quality and accuracy of the laser cutting process. Regular cleaning and inspection of the lens are necessary to ensure optimal performance.