Trepanning

Trepanning

Unlike trepanning, helical drilling does not involve the creation of a pilot hole. Right from the start, the laser begins moving in circles over the material as the pulses are delivered, with a large amount of material shooting upward in the process. The laser continues to work its way through the hole in a downward spiral. The focus, meanwhile, can be adjusted so that it is always at the base of the hole. Once the laser has pierced through the material, it can complete a few more revolutions to enlarge the base of the hole and smooth out the edges. Helical drilling makes it possible to produce very large and deep high-quality holes.