High Dynamics Focus Shift for Laser Beam Welding and Cutting

High Process Speed and Quality Through Controlled Energy Distribution

Lasers are used today in a wide variety of industrial applications in order to further optimize production processes and guarantee high workpiece quality. Laser machining processes can as well be significantly improved by high-frequency oscillation of the laser beam in the XY plane. Increasing requirements in industry, however, demand not only a fast motion in the plane, but also a fast active vertical shift of the beam energy in the workpiece, e.g. to further increase the usable feed rate during laser beam cutting of thick sheet metal or to enable better weld seam quality and process stability during laser beam welding. With a new Z axis focus shifter module, it is possible to extend the conventional methods and also 2-D beam manipulation in the XY machining plane by a highly dynamic movement in the direction of the beam axis, thereby increasing the machining speed and improving the machining quality.

Benefits of the High Dynamics Z Axis Focus Shifter Module

Faster process speed through controlled energy distribution in the workpiece
Influence of the melt pool dynamics by highly dynamic oscillation of the focus position
Compact design for simple integration into existing laser processing heads
High reliability due to wear-free guides and actuator technology as well as process-relevant temperature management
High economic efficiency through process optimization with low implementation effort

Features of the Z Axis Focus Shifter Module

  • Piezo-based aspheric membrane deformation to avoid imaging errors
  • Elliptical mirror substrate for maximum beam aperture exhaustion
  • Dielectric coating for high reflectivity
  • Use of >> PICA Thru© Ring Actuators

Preliminary Technical Data of the Prototype

  • Drive frequency to 2 kHz
  • A travel range of 28 μm achieves a mean shift of the focal plane, for example, by 15 mm with an appropriate optical setup
  • Versatile application possibilities due to variable module and optic design


The Z axis focus shifter module was developed within the framework of the PISTOL3 project in cooperation between PI, Fraunhofer IOF, Fraunhofer IWS and the industrial partners Kjellberg Finsterwalde, Heliatek and Optics Balzers. The PISTOL3 project is part of the “Zwanzig20-Partnerschaft für Innovation” funding program that is supported by the >> German Federal Ministry of Education and Research, the Bundesministerium für Bildung und Forschung (BMBF).

Focus Shifter Module in Operation

Further Applications That Benefit from the Z Axis Focus Shifter Module



Automation Platforms for Laser Material Processing

Precision – Throughput – Synchronized Motion

Version / Date
BRO67E R1 2018-06
pdf - 3 MB
Version / Date
BRO67CN 2018-11
pdf - 12 MB

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