Joerg Volpp
YOU?
Author Swipe
View article: Stagnating surface tension below boiling temperature during laser illumination
Stagnating surface tension below boiling temperature during laser illumination Open
Many laser processes include melting of material. Often, the material is overheated and reaches temperatures close or even above boiling temperature. However, many material properties at such high temperatures are often not known. A very i…
View article: AM by scanned laser melting of binder-based metal powder sheets
AM by scanned laser melting of binder-based metal powder sheets Open
A recently developed technique to feed metal as feedstock for additive manufacturing is the embedding of metal powder in long sheets through a polymer binder, termed the MAPS technique. The sheet is placed on top of the part during buildin…
View article: High-speed laser-directed energy deposition of crack-free wear-resistant and anti-corrosive Al/Cu bimetal components
High-speed laser-directed energy deposition of crack-free wear-resistant and anti-corrosive Al/Cu bimetal components Open
Al/Cu bimetal components (BMCs) possess higher thermal conductivity, better wear resistance and corrosion resistance than Al and Al alloys. It is a big challenging task to fabricate a high-performance Al/Cu BMC by a conventional infrared (…
View article: Surface tension derivation from laser-generated keyholes
Surface tension derivation from laser-generated keyholes Open
Surface tension is an essential material property that defines many aspects of thermal processes involving liquids. Metal materials have high melting temperatures, and surface tension could often be measured around melting temperature and …
View article: Surface Tension Estimation of Steel above Boiling Temperature
Surface Tension Estimation of Steel above Boiling Temperature Open
Surface tension is an important characteristic of materials. In particular at high temperatures, surface tension values are often unknown. However, for metals, these values are highly relevant in order to enable efficient industrial proces…
View article: Drop Detachment Under Intense Laser Irradiation
Drop Detachment Under Intense Laser Irradiation Open
During laser processing, complex effects can occur regarding the laser-material interactions. A high laser energy input leads to surface melting and even boiling. The resulting recoil pressure can create the so-called keyhole, a vapor chan…
View article: Influence of buoyancy on phase separation during laser melting of Silicon and Iron ore
Influence of buoyancy on phase separation during laser melting of Silicon and Iron ore Open
Phase separation is a well-known effect in liquid-liquid interactions, which can also occur during laser-related processes such as laser melting and laser alloying. However, the mechanism of phase separation between immiscible liquids on a…
View article: Impact of Melt Flow and Surface Tension on Gap Bridging During Laser Beam Welding
Impact of Melt Flow and Surface Tension on Gap Bridging During Laser Beam Welding Open
Laser beam welding is an essential technology to enable the transformation to enforce e-mobility. When manufacturing light weight structures like the chassis, precision, speed, quality and low deformation can be expected when using the las…
View article: Spectral Visualization of Alloy Reactions during Laser Melting
Spectral Visualization of Alloy Reactions during Laser Melting Open
Laser materials processing includes rapid heating to possibly high temperatures and rapid cooling of the illuminated materials. The material reactions can show significant deviations from equilibrium processing. During processing of comple…
View article: Surface tension of metals at high temperatures
Surface tension of metals at high temperatures Open
Surface tension is a material property that is needed to describe fluid behaviour, which impacts industrial processes, in which molten material is created, such as thermal cutting, welding and Additive Manufacturing. In particular when usi…
View article: Laser light absorption and Brewster angle on liquid metal
Laser light absorption and Brewster angle on liquid metal Open
Laser light absorption occurs in all laser-based processes and is, therefore, of importance for process simulation input, parameter optimization, and understanding of the occurring phenomena, such as melt pool flow or vaporization effects.…
View article: Impact of melt flow and surface tension on gap bridging during laser beam welding
Impact of melt flow and surface tension on gap bridging during laser beam welding Open
Laser beam welding is an essential technology to enable the transformation to enforce e-mobility. When manufacturing light weight structures like the chassis, precision, speed, quality and low deformation can be expected when using the las…
View article: Laser beam absorption measurement at molten metal surfaces
Laser beam absorption measurement at molten metal surfaces Open
Laser light absorption is one of the elementary effects of laser material processing. Absorption values are relevant to calculate the process efficiency and predict the impact on the material for the increasingly used laser processes. Howe…
View article: Multispot laser welding for increased gap bridgability
Multispot laser welding for increased gap bridgability Open
Laser beam welding is a promising technology to enable automated high-quality welding procedures at significantly higher processing speeds compared to conventional processes. However, its usability is often limited by gap bridgability. Thi…
View article: Influence of secondary-pass laser treatment on retained ferrite and martensite in 44MnSiVS6 microalloyed steel
Influence of secondary-pass laser treatment on retained ferrite and martensite in 44MnSiVS6 microalloyed steel Open
Overlapping regions of laser surface treatment are necessary features when processing large surface areas or cylindrical specimens. However, complex microstructural changes that appear in the regions with multiple heat treatment can affect…
View article: Acoustic emissions in directed energy deposition processes
Acoustic emissions in directed energy deposition processes Open
Acoustic emissions in directed energy deposition processes such as wire arc additive manufacturing and directed energy deposition with laser beam/metal are investigated within this work, as many insights about the process can be gained fro…
View article: Gas flow study for development of a novel shielding gas nozzle for directed energy deposition processes using computational fluid dynamic simulations
Gas flow study for development of a novel shielding gas nozzle for directed energy deposition processes using computational fluid dynamic simulations Open
Directed energy deposition (DED) enables the additive manufacturing of several materials such as molybdenum alloys that are very difficult to process by conventional methods. Some of these materials are highly reactive to gases in ambient …