Mapping and pocketing techniques for laser marking of 2D shapes on 3D curved surfaces

Abstract

Laser marking has been used since the invention of lasers but it is only in the last decade that it started evolving into 3D surface marking. The problem of defining the toolpath for a 3 axis laser marking machine can seem to be the same as the definition of the toolpath for the CNC milling machines but this is not completely true. In the case of laser marking is not only the last pass that will affect surface finish but every pass made. This implies that to obtain the desired final effect on the material it is crucial to define different pocketing and filling patterns together with the laser parameters. Defining new patterns that meet the requirements for the laser marking on 3D curved surface is a non-trivial problem; the toolpaths, depending on the application, may need to have different properties such as constant distance or density between path lines, non-crossing of path lines or defined angle of intersection. When trying to mark non flat surfaces with 2D images or paths, in certain cases, distortion of the 2D space cannot be avoided. This paper will analyze different proposed techniques for mapping and marking 3D solids with a 3 axes, mirror based, laser marking CNC machine analyzing advantages and disadvantages of each one from the software development point of view.