Study of laser engraving of materials assigned for flexoplates making

Experiments on CO₂ laser engraving of a series of photopolymerized plates from BASF and DuPont assigned for manufacture of flexo printing plates were carried out. The analysis of the obtained relief was performed by triangulation method providing measuring accuracy of about 10 microns. 2D and 3D profiles of printing elements of reverse line type were investigated. The relief depth and angle of base were determined depending on irradiation energy density on polymer surface in the range of 5·10⁵ - 1.7-·10⁶ J/m². It is found that relief parameters weakly depend on a type of the used photopolymer plates. Optimum values for flexo printing plates with screen Iineature right up to 48 lines/cm are obtained at energy density of 6·10⁵-1·10⁶ J/m².