is easily adjustable by a software tool to accommodate
many different cutting tasks. Nevertheless, tuning of the
oscillation parameters according to each task is still the
secret of success. Expert attention has to be paid to peripheral conditions such as the material, sheet thickness,
optical setup and laser source.
One routine related to static beam shaping is adapting the optical setup to varying tasks. Thin sheet cutting
usually requires small focus spots, whereas thick plates
are preferably separated by focus spots around 200 μm.
The change requires mechanical replacement of the optics. With DBS augmented laser beam cutting, a shift to
thick plate cutting can take place without mechanical
adaptions and therefore without any operator interaction. The proper beam characteristic for a certain cutting
task becomes a smart parameter, stored in a database and
controlled by the programmable logic controller. Just one
universal optical setup is required. In addition to trimming one production step, this eliminates the need to
keep multiple optics in stock and reduces the possibility
of error during the adaptation process.
Besides providing a user-friendly system, DBS also
improves feed rate and cut edge quality. Increasing the
achievable feed rate allows more parts to be manufactured and reduces costs per cutting meter. A higher feed
rate also flattens the cut front angle. This enlarges the interaction area of laser beam and material surface, reduces
transmitted power loss, and enhances process efficiency.
This greater efficiency means that almost every solid-state laser can use DBS for thick plate cutting. In case
of laser beam fusion cutting of stainless and mild steel
above 8-mm sheet thickness, a productivity increase up
to 200 percent is possible without any accompanying increase in power. The cut quality of DBS also is improved
compared with static beam shaping at the same power
level. Process stability is similar to established industry
standards. In combination with common sensor systems
and refined signal evaluation, even a smart process is
With stainless steel, DBS reduces post-treatments to a
minimum because the dross attachment is significantly
decreased and the generated kerf is almost parallel.
So far it has not been possible to cut mild steel plates
above 8-mm sheet thickness by a laser fusion cutting
process with acceptable quality. DBS, however, can
yield dross-free, nonoxidized edges. The results of laser
beam fusion cutting for both stainless and mild steel
are achieved with 3 kW and are of comparable quality
to results achieved with higher laser power and static
beam shaping (Figure 4). The reduction of subsequent
post-processes enabled by DBS also means a reduction of
work time and necessary machinery compared to other
DBS also provides more applications for laser beam
ablation such as piercing and drilling and makes it possible to work with materials such as aluminum that traditionally have been difficult to separate with lasers.
Meet the authors
Cindy Goppold is research associate in the department of laser
ablation and cutting at the Fraunhofer Institute for Material
and Beam Technology IWS in Dresden, Germany; e-mail:
Thomas Pinder is a research associate in the department of
laser ablation and cutting at Fraunhofer IWS; e-mail: thomas.
Patrick Herwig leads the laser cutting group at Fraunhofer
IWS, focusing on efficiency and quality improvements for conventional laser cutting processes and the development of new
technologies; e-mail: email@example.com.
1. D. Belforte (2017). Industrial lasers continue solid revenue
growth in 2016. Industrial Laser Solutions, Vol. 32, Issue 1.
2. P. Hilton and A. Gillner (2016). Portfolio and trend analysis
for laser based manufacturing EU-funded projects and
markets. EU-Report BU33 04/77 B-1049.
Figure 2. Implementation of DBS requires a high-dynamic 2D-scanner unit in addition to standard components. The scanner is installed between collimation
and the cutting head.
Figure 3. As this diagnostic of DBS patterns shows, an infinite amount of arbitrary beam movements is possible.
Figure 4. Cut edges created by DBS at 3-k W laser power of the two main materials in metal processing: mild (left)
and stainless steel (right). With stainless steel, DBS reduces post-treatments to a minimum, while mild steel plates
are dross-free and nonoxidized.
In contrast to the static beam
shaping, dynamic beam shaping
(DBS) is a spatiotemporal method
during the cutting process and
is variable at any time.