Highly dynamic axes systems for kW laser radiation have a different optics design. There are differentiations between preobjective and post-objective scanning. The focus diameter is relevant for the process and is determined by the beam quality of the laser, the beam aperture and the focal length of the optical system.
The size of the processing field and the working distance to the focal plane are also characteristic parameters. The later defines besides the mirror mass also the dynamic properties of the beam spot on the part. Commercially available systems achieve processing speeds of up to 20 m s-1. However, scanner systems are limited with respect to maximum dynamics.
To compare processing systems technical specifications can be used. It is also important however, to consider type and flexibility of the axes control systems, which are critical to whether or not a system can be used for a particular application. Fraunhofer engineers developed measurement routines to compare the dynamics of different scanner systems. Dynamic behavior, characterized by positioning deviations are quantified based on reference contours.
In the most simple case target and actual position data are compared. If the system does not provide external positioning information reference engravings are measured using fast pulsed lasers. The dynamic behavior during harmonic oscillations is characterized with amplitude-frequency dependencies (Bode diagram). To compare beam scanner systems from different manufacturers, it was also necessary to develop a family of control modules for using each of the systems.