LASER ENGRAVING MACHINE FOR PRINTING ROTARY SCREENS & FLEXOGRAPHIC ROLLERS AND SLEEVES
DIRECT LASER ENGRAVING SYSTEM
The laser engraving machine has two main parts: a laser source and a controller system. The beam emitted from the laser allows the controller to trace patterns onto the surface of the roller. The controller (computer) controls the direction, intensity, speed of movement, and spread of the laser beam aimed at the surface. The point where the laser beam touches the surface of the roller should be on the focal plane of the laser’s optical system, and is usually synonymous with its focal point. This point is typically small, less than a fraction of a millimeter (depending on the optical wavelength). Only the area inside this focal point is significantly affected when the laser beam passes over the surface. The energy delivered by the laser changes the surface of the material under the focal point. This is how material is removed from the surface to create an engraving. The surface material is vaporized during laser engraving, ventilation through the use of blowers and a vacuum pump that are required to remove the fumes arising from this process, and for removal of debris on the surface to allow the laser to continue engraving. The speed at which the beam moves across the material is also considered in creating engraving patterns. Changing the intensity and spread of the beam allows more flexibility in the design. For example, by changing the proportion of time (known as “duty-cycle”) the laser is turned on during each pulse, the power delivered to the engraving surface can be controlled appropriately for the material.