Through the active modulation of the intensity waveform and the independent change in the energy of each Laser Engraver pulse, the shape, diameter and depth of each single cell can be independently determined. This new type of mesh in the printing plate manufacturing process is called a Super Halfautotypical mesh (SHC), which is an extension of the Halfautotypical mesh (the depth and diameter of the semi-automatic mesh are variable, but cannot be controlled independently).
SHC modulation enables a single laser system to sculpt various meshes (traditional, Autotypical, Halfautotypical). In the past, different processes were required (electromechanical engraving, chemical etching). New mesh shapes can now be generated to optimize ink transfer characteristics and printability for each color% -tone value and printed substrate.
In addition to the "single shot and single hole" method of SHC beam waveform modulation, it is also possible to design engraving meshes by superimposing continuous laser pulses, but the diameter of the light spot is smaller than the required mesh size (such as the diameter of the light spot 10-15 Micron, cell size 100 microns). The shape and internal structure of the formed cavity depends on the scanning scheme of modulation, overlap and laser pulses (such as the scanning algorithm of image typesetting machine).
The continuous wave Laser Engraver is switched or gray-scale modulated, and can sculpt fine overlapping stripes to form a rhombic mesh. Its advantage lies in the high resolution of the image (for example, the resolution reaches 1000 lines / cm and the light spot diameter is 15-20 microns when the forward conveying step size is 10 microns). The disadvantage lies in the loss of production capacity, which needs to be compensated by using a higher modulation frequency (about 1 MHz) and a multi-beam engraving head.
Because of its high peak power when focusing, high-brightness fiber lasers (200-600 watts, continuous wave, pulse modulation) or ultra-short pulse lasers can achieve this advanced engraving method. In addition to zinc, this high brightness can also be used for engraving other materials, such as copper and ceramics.