P RE S S RE LE AS E
One arc, two wires and a laser:
HoDopp – high power deposition welding
Instead of completely exchanging expensive components
after wear and tear, these can be repaired using deposition
welding. Up to now, a gas metal arc welding (GMAW) process has usually been used for deposition welding, with an
average deposition rate of five kilos per hour. Since the dilution level is around 30 percent, several layers must be deposited, one on the other, until the protective covering is
pure enough. Scientists at the Laser Zentrum Hannover e.V.
(LZH) have now, as part of the project HoDopp, developed a
laser-supported, arc process, which achieves this in a single layer.
 Press release
Hannover, March11th, 2015
 Contact
Lena Bennefeld
Marketing & Communications
+49 511 2788-238
presse@lzh.de
In the conventional process, the arc burns between the wire electrode and the workpiece, and fuses both. For large area and multilayer coatings, the process can take up to 24 hours per square
meter. On the other hand, in the process used by the LZH, an arc
burns between two wires and melts them simultaneously. The
deposition rate can thus be increased to around 7.5 kg per hour.
The laser beam, which is used in addition to this, assures layer
adherence, and improves the form of the seam.
Low thermal stress on the components
Due to the support by the laser beam, the layer is deposited with a
low penetration depth, and the dilution rate is thus under five percent. A further advantage of the process is low heat input. Component deformation is notably lower than with deposition welding
using conventional GMAW, and the deposition rate can be increased by around 50%. Since one layer replaces two or three
conventionally deposited layers, time and material can be saved
for inhomogeneous materials, by half to two-thirds. Thus, productivity and simultaneously the quality of the welding process can be
drastically increased.
Editing:
Dipl.-Biol. Lena Bennefeld | Marketing & Communications | +49 511 2788-238 | presse@lzh.de
Laser Zentrum Hannover e.V. | Hollerithallee 8 | 30419 Hannover, Germany | +49 511 2788-0 | www.lzh.de
The project HoDopp: “High-power laser cladding using the twinwire technique without arc transmission and with laser-assisted
weld-penetration control” was financed by the Federal Ministry of
Education and Research (BMBF). The project was completed at
the end of 2014.
The LZH is presenting the process setup and finished components
at the Hannover Messe 2015, at the joint stand of the State of
Lower Saxony, hall 2, stand A08.
There are three figures and a video for this press release.
Caption figure 1: The laser supported process is characterized by a smaller heat affected zone, a lower welding
depth, and thus a lower dilution rate (layer height around 4 mm) (Photo: LZH)
Caption figure 2: Schematic drawing of the laser supported deposition welding process of the LZH (Graphics:
LZH)
Editing:
Dipl.-Biol. Lena Bennefeld | Marketing & Communications | +49 511 2788-238 | presse@lzh.de
Laser Zentrum Hannover e.V. | Hollerithallee 8 | 30419 Hannover, Germany | +49 511 2788-0 | www.lzh.de
Caption figure 3: Setup of the laser supported welding process. (Photo: LZH)
Caption video 1: Infrared camera process video showing the laser-induced melt movement. (Video: LZH)
Laser Zentrum Hannover e.V. (LZH)
As an independent, non-profit research institute, the Laser Zentrum Hannover e.V. (LZH) stands for innovative
research, development and consulting. The LZH is supported by the Lower Saxony Ministry for Economics, Labour and Transport and is dedicated to the selfless promotion of applied research in the field of photonics and
laser technology. Founded in 1986, over 170 employees are now working for the LZH.
The focus of the LZH lies on the fields of optical components and systems, optical production technologies, and
biomedical photonics. Interdisciplinary cooperation between natural scientists and mechanical engineers makes
innovative approaches to challenges from the most different areas possible: from the development of components
for specific laser systems to process developments for the most diverse laser applications, for example for medical technology or lightweight construction in the automotive sector. Seventeen spin off companies have emerged
Editing:
Dipl.-Biol. Lena Bennefeld | Marketing & Communications | +49 511 2788-238 | presse@lzh.de
Laser Zentrum Hannover e.V. | Hollerithallee 8 | 30419 Hannover, Germany | +49 511 2788-0 | www.lzh.de
from the LZH up to now. Thus, the LZH has created a strong transfer between fundamental science, application
oriented research, and industry.
Editing:
Dipl.-Biol. Lena Bennefeld | Marketing & Communications | +49 511 2788-238 | presse@lzh.de
Laser Zentrum Hannover e.V. | Hollerithallee 8 | 30419 Hannover, Germany | +49 511 2788-0 | www.lzh.de